Content

<div align="center"> <h2 id="claude-code-community-guide">Claude Code Guide</h2> _For updates and contributions, visit the [official Claude Code documentation](https://code.claude.com/docs/en/overview)_ ![Claude Code](https://img.shields.io/npm/v/@anthropic-ai/claude-code?label=Claude%20Code&logo=anthropic) [![Status](https://img.shields.io/badge/Status-Active-brightgreen)](https://github.com/anthropics/claude-code) [![License](https://img.shields.io/badge/License-Anthropic-orange)](https://claude.ai/code) </div> <div align="center"> <kbd> | Section | Status | | ------------------------------------------------- | ------ | | Guides on how to install on Windows, Linux, MacOS | ✅ | | Tips and Tricks | ✅ | | MCP Overview with what to use | ✅ | | Community Guides | ✅ | | Troubleshooting | ✅ | | How to use Claude code the most optimal way | ✅ | ### Interact with Claude Code Via Discord Guide [Here!](https://github.com/zebbern/claude-code-discord) </kbd> #### Daily Updated [Claude Changelogs](https://github.com/zebbern/claude-code-guide/blob/main/CHANGELOG.md) #### Agent Security [SKILL.md files](https://github.com/zebbern/claude-code-guide/tree/main/skills) `\|/` How to create [agent-skills-guide](https://github.com/zebbern/agent-skills-guide) </div> --- <h3 id="content">Content</h3> _Quick links:_ [Install](#quick-start) · [Commands](#claude-commands) · [Shortcuts](#keyboard-shortcuts) · [MCP](#mcp-integration) · [Troubleshoot](#help--troubleshooting) - **[Getting Started](#getting-started)** - [Quick Start](#quick-start) - [Initial Setup](#initial-setup) - **[Configuration & Environment](#configuration--environment)** - [Environment Variables](#environment-variables) - [Configuration Files](#configuration-files) - **[Commands & Usage](#commands--usage)** - [Claude Commands](#claude-commands) - [Cheat Sheet](#cheat-sheet) - **[Interface & Input](#interface--input)** - [Keyboard Shortcuts](#keyboard-shortcuts) - [Vim Mode](#vim-mode) - **[Advanced Features](#advanced-features)** - [Thinking Mode](#thinking-keywords) - [Plan Mode](#plan-mode) - [Background Tasks](#background-tasks) - [Remote Sessions](#remote-sessions) - [Sub Agents](#sub-agents) - [Skills](#skills) - [MCP Integration](#mcp-integration) - [Hooks System](#hooks-system) - **[Security & Permissions](#security--permissions)** - [Dangerous Mode](#dangerous-mode) - [Security Best Practices](#security-best-practices-main) - **[Automation & Integration](#automation--integration)** - [Automation & Scripting](#automation--scripting-with-claude-code) - [Auto PR Review](#auto-pr-review-inline-comments) - [Issue Triage](#issue-triage-suggest-labels--severity) - **[Help & Troubleshooting](#help--troubleshooting)** - [Installation Issues](#installation--nodejs-issues) - [MCP Issues](#mcp-model-context-protocol-issues) - [Best Practices](#best-practices) - **[Third-Party Integrations](#third-party-integrations)** - [DeepSeek Integration](#deepseek-integration) --- <h1 id="getting-started">Getting Started</h1> **Enable sound alerts when claude completes the task:** > <kbd>claude config set --global preferredNotifChannel terminal_bell</kbd> <h2 id="quick-start">Quick Start</h2> > [!TIP] > **Send <mark>claude</mark> or <mark>npx claude</mark> in terminal to start the interface** > > **Go to [Help & Troubleshooting](#help--troubleshooting) to fix issues...** ```C # Node.js 18+⭐️ /*Universal Method */ npm install -g @anthropic-ai/claude-code -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # Windows /* Via CMD (npm) */ npm install -g @anthropic-ai/claude-code /* Via CMD (native) */ curl -fsSL https://claude.ai/install.cmd -o install.cmd && install.cmd && del install.cmd /* Via Powershell */ irm https://claude.ai/install.ps1 | iex -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # WSL/GIT /* Via Terminal */ npm install -g @anthropic-ai/claude-code /* Via Terminal */ curl -fsSL https://claude.ai/install.sh | bash -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # MacOS */ brew install node && npm install -g @anthropic-ai/claude-code -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # Linux /* Via Terminal */ sudo apt update && sudo apt install -y nodejs npm /* Via Terminal */ npm install -g @anthropic-ai/claude-code /* Via Terminal */ curl -fsSL https://claude.ai/install.sh | bash -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # Arch /* Via Terminal */ yay -S claude-code*/ -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # Docker /* Windows (CMD) */ docker run -it --rm -v "%cd%:/workspace" -e ANTHROPIC_API_KEY="sk-your-key" node:20-slim bash -lc "npm i -g @anthropic-ai/claude-code && cd /workspace && claude" /* macOS/Linux (bash/zsh)*/ docker run -it --rm -v "$PWD:/workspace" -e ANTHROPIC_API_KEY="sk-your-key" node:20-slim bash -lc 'npm i -g @anthropic-ai/claude-code && cd /workspace && claude' /* No bash Fallback */ docker run -it --rm -v "$PWD:/workspace" -e ANTHROPIC_API_KEY="sk-your-key" node:20-slim sh -lc 'npm i -g @anthropic-ai/claude-code && cd /workspace && claude' --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # Check if claude is installed correctly /* Linux */ which claude /* Windows */ where claude /* Universal */ claude --version -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- # Common Management /*claude config */ Configure settings /*claude mcp list */ Setup MCP servers, you can also replace "list" with add/remove /*claude /agents */ Configure/Setup Subagents for different tasks /*claude update */ Update to latest ``` --- > [!Tip] > <ins>**Open Project Via Terminal Into VS Code / Cursor**</ins> > > ### $ - <kbd>cd /path/to/project</kbd> > > ### $ - <kbd>code .</kbd> > > **Make sure you have the <mark>(Claude Code extension)</mark> installed in your VS Code / Cursor** --- <h2 id="system-requirements">System Requirements</h2> > - OS: macOS 10.15+, Ubuntu 20.04+/Debian 10+, or Windows 10/11 or WSL > - Hardware: 4GB RAM minimum 8GB+ recommended > - Software: Node.js 18+ or git 2.23+ (optional) & GitHub or GitLab CLI for PR workflows (optional) > - Internet: Connection for API calls > - Node.js 18+ --- <h2 id="initial-setup">Initial Setup</h2> > [!Tip] > **Find API key from [Anthropic Console](https://console.anthropic.com)** > > **Do NOT commit real keys use git-ignored files, OS key stores, or secret managers** ```C # Universal /* start login process */ claude /login /* Setup long-lived authentication token */ claude setup-token ---------------------------------------------------------------------------------------------------------------------------------- # Windows /* Set-api-key */ set ANTHROPIC_API_KEY=sk-your-key-here-here /* cmd-masked-check */ echo OK: %ANTHROPIC_API_KEY:~0,8%*** /* Set-persistent-key */ setx ANTHROPIC_API_KEY "sk-your-key-here-here" /* cmd-unset-key */ set ANTHROPIC_API_KEY= ---------------------------------------------------------------------------------------------------------------------------------- # Linux /* Set-api-key */ export ANTHROPIC_API_KEY="sk-your-key-here-here" /* masked-check */ echo "OK: ${ANTHROPIC_API_KEY:0:8}***" /* remove-session */ unset ANTHROPIC_API_KEY ---------------------------------------------------------------------------------------------------------------------------------- # Powershell /* ps-session */ $env:ANTHROPIC_API_KEY = "sk-your-key-here-here" /* ps-masked-check */ "OK: $($env:ANTHROPIC_API_KEY.Substring(0,8))***" /* ps-persist */ [Environment]::SetEnvironmentVariable("ANTHROPIC_API_KEY","sk-your-key-here-here","User") /* ps-rotate */ $env:ANTHROPIC_API_KEY = "sk-new-key" /* ps-remove */ Remove-Item Env:\ANTHROPIC_API_KEY ---------------------------------------------------------------------------------------------------------------------------------- # Other... # persist-bash/* */ echo 'export ANTHROPIC_API_KEY="sk-your-key-here-here"' >> ~/.bashrc && source ~/.bashrc # persist-zsh /* */ echo 'export ANTHROPIC_API_KEY="sk-your-key-here-here"' >> ~/.zshrc && source ~/.zshrc # persist-fish/* */ fish -lc 'set -Ux ANTHROPIC_API_KEY sk-your-key-here-here' ---------------------------------------------------------------------------------------------------------------------------------- ``` --- <h1 id="configuration--environment">Configuration & Environment</h1> <h2 id="environment-variables">Environment Variables</h2> > **You can also set any of these in settings.json under the "env" key for automatic application.** > [!Important] > **Windows Users replace <kbd>export</kbd> with <kbd>set</kbd> or <kbd>setx</kbd> for perm** ```bash # Environment toggles (put in ~/.bashrc or ~/.zshrc) export ANTHROPIC_API_KEY="sk-your-key-here-here" # API key sent as X-Api-Key header (interactive usage: /login) export ANTHROPIC_AUTH_TOKEN="my-auth-token" # Custom Authorization header; Claude adds "Bearer " prefix automatically export ANTHROPIC_CUSTOM_HEADERS="X-Trace-Id: 12345" # Extra request headers (format: "Name: Value") export ANTHROPIC_MODEL="claude-sonnet-4-20250514" # Custom model name to use export ANTHROPIC_DEFAULT_SONNET_MODEL="claude-sonnet-4-20250514" # Default Sonnet model alias export ANTHROPIC_DEFAULT_OPUS_MODEL="claude-opus-4-6-20260130" # Default Opus model alias (Opus 4.6 now available) export ANTHROPIC_SMALL_FAST_MODEL="haiku-model" # Haiku-class model for background tasks (placeholder) export ANTHROPIC_SMALL_FAST_MODEL_AWS_REGION="REGION" # Override AWS region for the small/fast model on Bedrock (placeholder) export AWS_BEARER_TOKEN_BEDROCK="bedrock_..." # Amazon Bedrock API key/token for authentication export BASH_DEFAULT_TIMEOUT_MS=60000 # Default timeout (ms) for long-running bash commands export BASH_MAX_TIMEOUT_MS=300000 # Maximum timeout (ms) allowed for long-running bash commands export BASH_MAX_OUTPUT_LENGTH=20000 # Max characters in bash outputs before middle-truncation export CLAUDE_BASH_MAINTAIN_PROJECT_WORKING_DIR=1 # (0 or 1) return to original project dir after each Bash command export CLAUDE_CODE_API_KEY_HELPER_TTL_MS=600000 # Interval (ms) to refresh creds when using apiKeyHelper export CLAUDE_CODE_IDE_SKIP_AUTO_INSTALL=1 # (0 or 1) skip auto-installation of IDE extensions export CLAUDE_CODE_MAX_OUTPUT_TOKENS=4096 # Max number of output tokens for most requests export CLAUDE_CODE_USE_BEDROCK=1 # (0 or 1) use Amazon Bedrock export CLAUDE_CODE_USE_VERTEX=0 # (0 or 1) use Google Vertex AI export CLAUDE_CODE_SKIP_BEDROCK_AUTH=0 # (0 or 1) skip AWS auth for Bedrock (e.g., via LLM gateway) export CLAUDE_CODE_SKIP_VERTEX_AUTH=0 # (0 or 1) skip Google auth for Vertex (e.g., via LLM gateway) export CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC=0 # (0 or 1) disable nonessential traffic (equivalent to DISABLE_* below) export CLAUDE_CODE_DISABLE_TERMINAL_TITLE=0 # (0 or 1) disable automatic terminal title updates export CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1 # (0 or 1) enable agent teams research preview export CLAUDE_CODE_ADDITIONAL_DIRECTORIES_CLAUDE_MD=1 # (0 or 1) load CLAUDE.md from --add-dir paths export CLAUDE_CODE_ENABLE_TASKS=false # Set to "false" to disable new task system export DISABLE_AUTOUPDATER=0 # (0 or 1) disable automatic updates (overrides autoUpdates setting) export DISABLE_BUG_COMMAND=0 # (0 or 1) disable the /bug command export DISABLE_COST_WARNINGS=0 # (0 or 1) disable cost warning messages export DISABLE_ERROR_REPORTING=0 # (0 or 1) opt out of Sentry error reporting export DISABLE_NON_ESSENTIAL_MODEL_CALLS=0 # (0 or 1) disable model calls for non-critical paths export DISABLE_TELEMETRY=0 # (0 or 1) opt out of Statsig telemetry export HTTP_PROXY="http://proxy:8080" # HTTP proxy server URL export HTTPS_PROXY="https://proxy:8443" # HTTPS proxy server URL export MAX_THINKING_TOKENS=0 # (0 or 1 to turn off/on) force a thinking budget for the model export MCP_TIMEOUT=120000 # MCP server startup timeout (ms) export MCP_TOOL_TIMEOUT=60000 # MCP tool execution timeout (ms) export MAX_MCP_OUTPUT_TOKENS=25000 # Max tokens allowed in MCP tool responses (default 25000) export USE_BUILTIN_RIPGREP=0 # (0 or 1) set 0 to use system-installed rg instead of bundled one export VERTEX_REGION_CLAUDE_3_5_HAIKU="REGION" # Region override for Claude 3.5 Haiku on Vertex AI export VERTEX_REGION_CLAUDE_3_5_SONNET="REGION" # Region override for Claude 3.5 Sonnet on Vertex AI export VERTEX_REGION_CLAUDE_3_7_SONNET="REGION" # Region override for Claude 3.7 Sonnet on Vertex AI export VERTEX_REGION_CLAUDE_4_0_OPUS="REGION" # Region override for Claude 4.0 Opus on Vertex AI export VERTEX_REGION_CLAUDE_4_0_SONNET="REGION" # Region override for Claude 4.0 Sonnet on Vertex AI export VERTEX_REGION_CLAUDE_4_1_OPUS="REGION" # Region override for Claude 4.1 Opus on Vertex AI export VERTEX_REGION_CLAUDE_4_6_OPUS="REGION" # Region override for Claude 4.6 Opus on Vertex AI ``` <h2 id="global-config-options">Global Config Options</h2> ```bash claude config set -g theme dark # Theme: dark | light | light-daltonized | dark-daltonized claude config set -g preferredNotifChannel iterm2_with_bell # Notification channel: iterm2 | iterm2_with_bell | terminal_bell | notifications_disabled claude config set -g autoUpdates true # Auto-download & install updates (applied on restart) claude config set -g verbose true # Show full bash/command outputs claude config set -g includeCoAuthoredBy false # Omit "co-authored-by Claude" in git commits/PRs claude config set -g forceLoginMethod console # Restrict login to Anthropic Console (API billing) claude config set -g model "claude-3-5-sonnet-20241022" # Default model override claude config set -g statusLine '{"type":"command","command":"~/.claude/statusline.sh"}' # Custom status line claude config set -g enableAllProjectMcpServers true # Auto-approve all MCP servers from .mcp.json claude config set -g enabledMcpjsonServers '["memory","github"]' # Approve specific MCP servers claude config set -g disabledMcpjsonServers '["filesystem"]' # Reject specific MCP servers ``` > [!Important] > **Windows Users replace <kbd>export</kbd> with <kbd>set</kbd>** ```bash export DISABLE_AUTOUPDATER=1 # Turn off automatic updates globally (overrides autoUpdates) export CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC=1 # Disable nonessential traffic (equiv. to DISABLE_* toggles below) export DISABLE_TELEMETRY=1 # Opt out of Statsig telemetry export DISABLE_ERROR_REPORTING=1 # Opt out of Sentry error reporting export DISABLE_BUG_COMMAND=1 # Disable the /bug command export DISABLE_COST_WARNINGS=0 # Keep cost warnings (set 1 to hide) export DISABLE_NON_ESSENTIAL_MODEL_CALLS=1 # Skip non-critical model calls (flavor text, etc.) export CLAUDE_CODE_DISABLE_TERMINAL_TITLE=1 # Stop auto-updating terminal titles export CLAUDE_BASH_MAINTAIN_PROJECT_WORKING_DIR=1 # Return to original project dir after each Bash command export CLAUDE_CODE_IDE_SKIP_AUTO_INSTALL=1 # Skip auto-installation of IDE extensions export USE_BUILTIN_RIPGREP=0 # Use system 'rg' (0) instead of bundled 'rg' export MAX_THINKING_TOKENS=0 # (0 or 1 to turn off/on) force a thinking budget for the model export CLAUDE_CODE_MAX_OUTPUT_TOKENS=4096 # Cap typical response size (example value) export HTTP_PROXY="http://proxy.company:8080" # HTTP proxy (if needed) export HTTPS_PROXY="https://proxy.company:8443" # HTTPS proxy (if needed) ``` <h2 id="configuration-files">Configuration Files</h2> **(Memory type) Claude Code offers four memory locations in a hierarchical structure, each serving a different purpose:** | Memory Type | Location | Purpose | Use Case Examples | Shared With | | -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------- | -------------------------------------------------------------------- | ------------------------------- | | **Enterprise policy** | macOS: `/Library/Application Support/ClaudeCode/CLAUDE.md`<br />Linux: `/etc/claude-code/CLAUDE.md`<br />Windows: `C:\ProgramData\ClaudeCode\CLAUDE.md` | Organization-wide instructions managed by IT/DevOps | Company coding standards, security policies, compliance requirements | All users in organization | | **Project memory** | `./CLAUDE.md` | Team-shared instructions for the project | Project architecture, coding standards, common workflows | Team members via source control | | **User memory** | `~/.claude/CLAUDE.md` | Personal preferences for all projects | Code styling preferences, personal tooling shortcuts | Just you (all projects) | | **Project memory (local)** | `./CLAUDE.local.md` | Personal project-specific preferences | _(Deprecated, see below)_ Your sandbox URLs, preferred test data | Just you (current project) | > All memory files are automatically loaded into Claude Code's context when launched. Files higher in the hierarchy take precedence and are loaded first, providing a foundation that more specific memories build upon. --- <h1 id="commands--usage">Commands & Usage</h1> <h2 id="claude-commands">Claude Commands</h2> | Command | Purpose | | :------------------------ | :--------------------------------------------------------------------- | | `/add-dir` | Add additional working directories | | `/agents` | Manage custom AI subagents for specialized tasks | | `/bug` | Report bugs (sends conversation to Anthropic) | | `/clear` | Clear conversation history | | `/compact [instructions]` | Compact conversation with optional focus instructions | | `/config` | Open the Settings interface (Config tab) | | `/context` | Visualize current context usage as a colored grid | | `/copy` | Copy conversation content to clipboard | | `/cost` | Show token usage statistics and billing information | | `/debug` | Troubleshoot current session and diagnose issues | | `/doctor` | Checks the health of your Claude Code installation | | `/exit` | Exit the REPL | | `/export [filename]` | Export the current conversation to a file or clipboard | | `/help` | Get usage help | | `/init` | Initialize project with CLAUDE.md guide | | `/insights` | Generate an interactive HTML report analyzing your coding habits | | `/keybindings` | Configure custom keyboard shortcuts | | `/login` | Switch Anthropic accounts | | `/logout` | Sign out from your Anthropic account | | `/mcp` | Manage MCP server connections and OAuth authentication | | `/memory` | Edit CLAUDE.md memory files | | `/model` | Select or change the AI model | | `/permissions` | View or update tool permissions | | `/plan` | Enter plan mode directly from the prompt | | `/pr_comments` | View pull request comments | | `/rename <name>` | Rename the current session for easier identification | | `/resume [session]` | Resume a conversation by ID or name, or open session picker | | `/review` | Request code review | | `/rewind` | Rewind the conversation and/or code to a previous point | | `/sandbox` | View sandbox dependency status with installation instructions | | `/stats` | Visualize daily usage, session history, streaks, and model preferences | | `/status` | Open Settings interface (Status tab) showing version, model, account | | `/statusline` | Set up Claude Code's status line UI | | `/tasks` | List and manage background tasks | | `/teleport` | Resume a remote session from claude.ai (subscribers only) | | `/terminal-setup` | Install Shift+Enter key binding for newlines (iTerm2 and VSCode only) | | `/theme` | Change the color theme | | `/todos` | List current TODO items | | `/usage` | Show plan usage limits and rate limit status (subscription plans) | | `/vim` | Enter vim mode for alternating insert and command modes | <h2 id="command-line-flags">Command Line Flags</h2> | Flag / Command | Description | Example | | :--------------------------------------------------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------- | :------------------------------------------------------------------------------------- | | `-d, --debug` | Enable debug mode (shows detailed debug output). | `claude -d -p "query"` | | `--include-partial-messages` | partial message streaming support via CLI flag | | `--mcp-debug` | [DEPRECATED] MCP debug mode (shows MCP server errors). Use `--debug` instead. | `claude --mcp-debug` | | `--verbose` | Override verbose mode setting from config (shows expanded logging / turn-by-turn output). | `claude --verbose` | | `-p, --print` | Print response and exit (useful for piping output). | `claude -p "query"` | | `--output-format <format>` | Output format (only works with `--print`): `text` (default), `json` (single result), or `stream-json` (realtime streaming). | `claude -p "query" --output-format json` | | `--input-format <format>` | Input format (only works with `--print`): `text` (default) or `stream-json` (realtime streaming input). | `claude -p --output-format stream-json --input-format stream-json` | | `--replay-user-messages` | Re-emit user messages from stdin back to stdout for acknowledgment — **only works with** `--input-format=stream-json` **and** `--output-format=stream-json`. | `claude --input-format stream-json --output-format stream-json --replay-user-messages` | | `--allowedTools`, `--allowed-tools <tools...>` | Comma/space-separated list of tool names to allow (e.g. `"Bash(git:*) Edit"`). | `--allowed-tools "Bash(git:*)" Edit"` | | `--disallowedTools`, `--disallowed-tools <tools...>` | Comma/space-separated list of tool names to deny (e.g. `"Bash(git:*) Edit"`). | `--disallowed-tools "Edit"` | | `--mcp-config <configs...>` | Load MCP servers from JSON files or strings (space-separated). | `claude --mcp-config ./mcp-servers.json` | | `--strict-mcp-config` | Only use MCP servers from `--mcp-config`, ignoring other MCP configurations. | `claude --mcp-config ./a.json --strict-mcp-config` | | `--append-system-prompt <prompt>` | Append a system prompt to the default system prompt (useful in print mode). | `claude -p --append-system-prompt "Do X then Y"` | | `--permission-mode <mode>` | Permission mode for the session (choices include `acceptEdits`, `bypassPermissions`, `default`, `plan`). | `claude --permission-mode plan` | | `--permission-prompt-tool <tool>` | Specify an MCP tool to handle permission prompts in non-interactive mode. | `claude -p --permission-prompt-tool mcp_auth_tool "query"` | | `--fallback-model <model>` | Enable automatic fallback to a specified model when the default is overloaded (note: only works with `--print` per help). | `claude -p --fallback-model claude-haiku-20240307 "query"` | | `--model <model>` | Model for the current session. Accepts aliases like `sonnet`/`opus` or a full model name (e.g. `claude-sonnet-4-20250514`). | `claude --model sonnet` | | `--settings <file-or-json>` | Load additional settings from a JSON file or a JSON string. | `claude --settings ./settings.json` | | `--add-dir <directories...>` | Additional directories to allow tool access to. | `claude --add-dir ../apps ../lib` | | `--ide` | Automatically connect to an IDE on startup if exactly one valid IDE is available. | `claude --ide` | | `-c, --continue` | Continue the most recent conversation in the current directory. | `claude --continue` | | `-r, --resume [sessionId]` | Resume a conversation; provide a session ID or interactively select one. | `claude -r "abc123"` | | `--session-id <uuid>` | Use a specific session ID for the conversation (must be a valid UUID). | `claude --session-id 123e4567-e89b-12d3-a456-426614174000` | | `--agents <json>` | Define custom subagents dynamically via JSON (see subagent docs for format). | `claude --agents '{"reviewer":{"description":"Reviews code","prompt":"..."}}'` | | `--agent <name>` | Specify a specific agent for the current session. | `claude --agent my-custom-agent` | | `--chrome` | Enable Chrome browser integration for web automation and testing. | `claude --chrome` | | `--no-chrome` | Disable Chrome browser integration for this session. | `claude --no-chrome` | | `--remote` | Create a new web session on claude.ai with the provided task description. | `claude --remote "Fix the login bug"` | | `--teleport` | Resume a web session in your local terminal. | `claude --teleport` | | `--fork-session` | When resuming, create a new session ID instead of reusing the original. | `claude --resume abc123 --fork-session` | | `--json-schema <schema>` | Get validated JSON output matching a JSON Schema after agent completes (print mode only). | `claude -p --json-schema '{"type":"object",...}' "query"` | | `--max-budget-usd <amount>` | Maximum dollar amount to spend on API calls before stopping (print mode only). | `claude -p --max-budget-usd 5.00 "query"` | | `--max-turns <n>` | Limit the number of agentic turns (print mode only). Exits with error when limit reached. | `claude -p --max-turns 3 "query"` | | `--betas <headers>` | Beta headers to include in API requests (API key users only). | `claude --betas interleaved-thinking` | | `--tools <tools>` | Restrict which built-in tools Claude can use. Use "" to disable all, "default" for all, or specific tool names. | `claude --tools "Bash,Edit,Read"` | | `--system-prompt <prompt>` | Replace the entire system prompt with custom text (works in interactive and print modes). | `claude --system-prompt "You are a Python expert"` | | `--system-prompt-file <file>` | Load system prompt from a file, replacing the default prompt (print mode only). | `claude -p --system-prompt-file ./custom-prompt.txt "query"` | | `--append-system-prompt-file <file>` | Load additional system prompt text from a file and append to default (print mode only). | `claude -p --append-system-prompt-file ./extra-rules.txt "query"` | | `--plugin-dir <dir>` | Load plugins from directories for this session only (repeatable). | `claude --plugin-dir ./my-plugins` | | `--setting-sources <sources>` | Comma-separated list of setting sources to load (user, project, local). | `claude --setting-sources user,project` | | `--no-session-persistence` | Disable session persistence so sessions are not saved to disk (print mode only). | `claude -p --no-session-persistence "query"` | | `--disable-slash-commands` | Disable all skills and slash commands for this session. | `claude --disable-slash-commands` | | `--dangerously-skip-permissions` | Bypass all permission checks (only for trusted sandboxes). | `claude --dangerously-skip-permissions` | | `-v, --version` | Show the installed `claude` CLI version. | `claude --version` | | `-h, --help` | Display help / usage. | `claude --help` | > The `--output-format json` flag is particularly useful for scripting and automation, allowing you to parse Claude's responses programmatically. <h2 id="cheat-sheet">Cheat Sheet</h2> ```md ## Claude Cheat Sheet # Basics / interactive claude # Start interactive REPL claude "explain this project" # Start REPL seeded with a prompt claude -p "summarize README.md" # Non-interactive print mode (SDK-backed) cat logs.txt | claude -p "explain" # Pipe input to Claude and exit claude -c # Continue most recent conversation (alias for --continue) claude -r "<session-id>" "finish this" # Resume specific session by ID (alias for --resume) claude --model claude-sonnet-4-20250514# Pick model for this run claude --max-turns 3 -p "lint this" # Cap agentic turns in print mode claude --replay-user-messages # Replay user messages to stdout for debugging / SDK workflows # Update & install claude update # Manually update Claude Code claude doctor # Diagnose install/version & setup claude install # Start native binary installer (beta) claude migrate-installer # Migrate from global npm to local installer # Config: interactive wizard + direct ops claude config # Interactive config wizard claude config get <key> # Get value (e.g., claude config get theme) claude config set <key> <val> # Set value (e.g., claude config set theme dark) claude config add <key> <vals…> # Append to array-type keys (e.g., claude config add env DEV=1) claude config remove <key> <vals…> # Remove items from list-type keys claude config list # Show all current settings for project (project scope is default) # Example project-scoped settings claude config set model "claude-3-5-sonnet-20241022" # Override default model for this project claude config set includeCoAuthoredBy false # Disable "co-authored-by Claude" byline in git/PRs claude config set forceLoginMethod claudeai # Restrict login flow: claudeai | console claude config set enableAllProjectMcpServers true # Auto-approve all MCP servers from .mcp.json claude config set defaultMode "acceptEdits" # Set default permission mode claude config set disableBypassPermissionsMode disable # Prevent bypassPermissions mode (example key) # Manage list settings (project scope) claude config add enabledMcpjsonServers github # Approve a specific MCP server from .mcp.json claude config add enabledMcpjsonServers memory # Add another claude config remove enabledMcpjsonServers memory # Remove one entry claude config add disabledMcpjsonServers filesystem # Explicitly reject a specific MCP server # Global scope (use -g or --global) claude config set -g autoUpdates false # Turn off automatic updates globally claude config set --global preferredNotifChannel iterm2_with_bell claude config set -g theme dark # Theme: dark | light | light-daltonized | dark-daltonized claude config set -g verbose true # Show full bash/command outputs everywhere claude config get -g theme # Confirm a global value # MCP (Model Context Protocol) management claude mcp # Launch MCP wizard / configure MCP servers claude mcp list # List configured MCP servers claude mcp get <name> # Show details for a server claude mcp remove <name> # Remove a server claude mcp add <name> <command> [args...] # Add local stdio server claude mcp add --transport sse <name> <url> # Add remote SSE server claude mcp add --transport http <name> <url> # Add remote HTTP server claude mcp add <name> --env KEY=VALUE -- <cmd> [args...] # Pass env to server command claude mcp add --transport sse private-api https://api.example/mcp \ --header "Authorization: Bearer TOKEN" # Add with auth header claude mcp add-json <name> '<json>' # Add server via JSON blob claude mcp add-from-claude-desktop # Import servers from Claude Desktop claude mcp reset-project-choices # Reset approvals for project .mcp.json servers claude mcp serve # Run Claude Code itself as an MCP stdio server # Other useful flags (print / SDK mode) claude --add-dir ../apps ../lib # Add additional working directories claude --allowedTools "Bash(git log:\*)" "Read" # Allow listed tools without permission prompts claude --disallowedTools "Edit" # Disallow listed tools without permission prompts claude --append-system-prompt "Custom instruction" # Append to system prompt (only with -p) claude -p "query" --output-format json --input-format stream-json # Control IO formats for scripting claude --verbose # Verbose logging (turn-by-turn) claude --dangerously-skip-permissions # Skip permission prompts (use with caution) claude --permission-mode plan # Start in plan mode (read-only analysis) claude --max-turns 3 -p "query" # Limit agentic turns (print mode only) claude --max-budget-usd 5.00 -p "query" # Cap spending per session (print mode only) claude --json-schema '{"type":"object"}' -p "query" # Get validated JSON output claude --chrome # Enable Chrome browser integration claude --remote "Fix the bug" # Create web session on claude.ai claude --teleport # Resume web session locally claude --agents '{"name":{...}}' # Define subagents via JSON # Session management claude -c # Continue most recent conversation claude -r "session-name" # Resume by name or ID claude --fork-session -r abc123 # Fork instead of reusing original /rename auth-refactor # Name current session /resume # Open session picker /export output.md # Export conversation to file # Quick verification / notes # - Project scope is default for 'claude config'; use -g/--global to affect all projects. # - Settings precedence: Enterprise > CLI args > local project > shared project > user (~/.claude). # - Use 'add' / 'remove' only with list-type keys (e.g., enabledMcpjsonServers). # - The CLI reference and release notes are the authoritative sources for flags and recent additions. ``` --- <h1 id="interface--input">Interface & Input</h1> <h2 id="keyboard-shortcuts">Keyboard Shortcuts</h2> | Shortcut | Description | Context | | :--------------------------- | :--------------------------------- | :--------------------------------------- | | `Ctrl+C` | Cancel current input or generation | Standard interrupt | | `Ctrl+D` | Exit Claude Code session | EOF signal | | `Ctrl+G` | Open in default text editor | Edit your prompt or custom response | | `Ctrl+L` | Clear terminal screen | Keeps conversation history | | `Ctrl+O` | Toggle verbose output | Shows detailed tool usage and execution | | `Ctrl+R` | Reverse search command history | Search through previous commands | | `Ctrl+V` or `Cmd+V` (iTerm2) | Paste image from clipboard | Pastes an image or path to an image file | | `Ctrl+B` | Background running tasks | Backgrounds bash commands and agents | | `Up/Down arrows` | Navigate command history | Recall previous inputs | | `Left/Right arrows` | Cycle through dialog tabs | Navigate between tabs in dialogs | | `Esc` + `Esc` | Rewind the code/conversation | Restore to a previous point | | `Shift+Tab` or `Alt+M` | Toggle permission modes | Switch between Auto-Accept, Plan, Normal | | `Option+P` (macOS) / `Alt+P` | Switch model | Switch models without clearing prompt | | `Option+T` (macOS) / `Alt+T` | Toggle extended thinking | Enable/disable extended thinking mode | <h3 id="text-editing">Text Editing</h3> | Shortcut | Description | Context | | :--------------------- | :--------------------------- | :------------------------------------ | | `Ctrl+K` | Delete to end of line | Stores deleted text for pasting | | `Ctrl+U` | Delete entire line | Stores deleted text for pasting | | `Ctrl+Y` | Paste deleted text | Paste text deleted with Ctrl+K/U | | `Alt+Y` (after Ctrl+Y) | Cycle paste history | Cycle through previously deleted text | | `Alt+B` | Move cursor back one word | Requires Option as Meta on macOS | | `Alt+F` | Move cursor forward one word | Requires Option as Meta on macOS | <h3 id="multiline-input">Multiline Input</h3> | Method | Shortcut | Context | | :--------------- | :------------- | :-------------------------------- | | Quick escape | `\` + `Enter` | Works in all terminals | | macOS default | `Option+Enter` | Default on macOS | | Terminal setup | `Shift+Enter` | After `/terminal-setup` | | Control sequence | `Ctrl+J` | Line feed character for multiline | | Paste mode | Paste directly | For code blocks, logs | <h3 id="quick-commands">Quick Commands</h3> | Shortcut | Description | Notes | | :----------- | :------------------------------- | :------------------------------------ | | `/` at start | Command or skill | See built-in commands and skills | | `!` at start | Bash mode | Run commands directly, add to context | | `@` | File path mention | Trigger file path autocomplete | | `#` at start | Memory shortcut add to CLAUDE.md | Prompts for file selection | > [!Tip] > **PDF Page Ranges:** Use the `pages` parameter with the Read tool for PDFs (e.g., `pages: "1-5"`). Large PDFs (>10 pages) return a lightweight reference when @-mentioned instead of being inlined. <h2 id="vim-mode">Vim Mode</h2> > [!Note] > Enable vim-style editing with `/vim` command or configure permanently via `/config`. <h3 id="vim-mode-switching">Vim Mode Switching</h3> | Command | Action | From mode | | :------ | :-------------------------- | :-------- | | `Esc` | Enter NORMAL mode | INSERT | | `i` | Insert before cursor | NORMAL | | `I` | Insert at beginning of line | NORMAL | | `a` | Insert after cursor | NORMAL | | `A` | Insert at end of line | NORMAL | | `o` | Open line below | NORMAL | | `O` | Open line above | NORMAL | <h3 id="vim-navigation">Vim Navigation</h3> | Command | Action | | :-------------- | :------------------------ | | `h`/`j`/`k`/`l` | Move left/down/up/right | | `w` | Next word | | `e` | End of word | | `b` | Previous word | | `0` | Beginning of line | | `$` | End of line | | `^` | First non-blank character | | `gg` | Beginning of input | | `G` | End of input | <h3 id="vim-editing">Vim Editing</h3> | Command | Action | | :------------- | :---------------------- | | `x` | Delete character | | `dd` | Delete line | | `D` | Delete to end of line | | `dw`/`de`/`db` | Delete word/to end/back | | `cc` | Change line | | `C` | Change to end of line | | `cw`/`ce`/`cb` | Change word/to end/back | | `.` | Repeat last change | > [!Tip] > Configure your preferred line break behavior in terminal settings. Run `/terminal-setup` to install Shift+Enter binding for iTerm2 and VS Code terminals. <h2 id="command-history">Command History</h2> > Claude Code maintains command history for the current session: ``` * History is stored per working directory * Cleared with `/clear` command * Use Up/Down arrows to navigate (see keyboard shortcuts above) * **Ctrl+R**: Reverse search through history (if supported by terminal) * **Note**: History expansion (`!`) is disabled by default ``` --- <h1 id="advanced-features">Advanced Features</h1> <h2 id="thinking-keywords">Thinking Keywords</h2> > [!Note] > **Gives Claude extra pre-answer planning time by adding ONE of these keywords to your prompt.** > **Order (lowest → highest) token consumption** > > <table><tr><td> > > > **<kbd>think</kbd> -------------> Lowest** > > > **<kbd>think hard</kbd>** > > > **<kbd>think harder</kbd>** > > > **<kbd>ultrathink</kbd> --------> Highest** > > </td></tr></table> <h3 id="this-makes-claude-spend-more-time">This makes Claude spend more time:</h3> 1. **Planning the solution** 2. #### breaking down steps 3. #### weighing alternatives/trade-offs 4. #### checking constraints & edge cases > > #### Higher levels usually increase **latency** and **token usage** pick the smallest that works. <h5 id="thinking-examples">Examples</h5> ```md # Small boost claude -p "Think. Outline a plan to refactor the auth module." # Medium boost claude -p "Think harder. Draft a migration plan from REST to gRPC." # Max boost claude -p "Ultrathink. Propose a step-by-step strategy to fix flaky payment tests and add guardrails." ``` <h2 id="fast-mode">Fast Mode</h2> > [!Note] > **Fast Mode provides accelerated response times for Opus 4.6, optimized for rapid iteration and quick tasks.** **How to enable Fast Mode:** ```bash # Enable fast mode in the REPL (requires extra-usage first) /extra-usage /fast # Or toggle during conversation # The status bar will show when Fast Mode is active ``` **Key features:** - **Faster responses** - Reduced latency for quick tasks - **Available for Opus 4.6** - New in version 2.1.36 - **Requires extra-usage** - Must enable `/extra-usage` first **When to use Fast Mode:** - Quick code reviews and edits - Rapid prototyping - Simple questions and commands - Iterative debugging > Fast Mode trades some depth for speed. Use normal mode for complex analysis and planning tasks. <h2 id="plan-mode">Plan Mode</h2> > [!Note] > **Plan Mode instructs Claude to analyze the codebase with read-only operations, perfect for exploring codebases, planning complex changes, or reviewing code safely.** **When to use Plan Mode:** - **Multi-step implementation**: When your feature requires making edits to many files - **Code exploration**: When you want to research the codebase thoroughly before changing anything - **Interactive development**: When you want to iterate on the direction with Claude **How to enable Plan Mode:** ```bash # Start a new session in Plan Mode claude --permission-mode plan # Or toggle during session with Shift+Tab # (cycles through: Normal → Auto-Accept → Plan Mode) # Enter plan mode from the prompt /plan # Run headless queries in Plan Mode claude --permission-mode plan -p "Analyze the authentication system and suggest improvements" ``` **Configure Plan Mode as default:** ```json // .claude/settings.json { "permissions": { "defaultMode": "plan" } } ``` --- <h2 id="background-tasks">Background Tasks</h2> > [!Note] > **Claude Code supports running bash commands in the background, allowing you to continue working while long-running processes execute.** **How to use background tasks:** | Method | Description | | :------------ | :------------------------------------------------------------------------- | | Prompt Claude | Ask Claude to "run this in the background" | | `Ctrl+B` | Move a running Bash tool invocation to background (tmux users press twice) | **Key features:** - Output is buffered and Claude can retrieve it using the TaskOutput tool - Background tasks have unique IDs for tracking and output retrieval - Background tasks are automatically cleaned up when Claude Code exits - Use `/tasks` to list and manage background tasks **Common backgrounded commands:** - Build tools (webpack, vite, make) - Package managers (npm, yarn, pnpm) - Test runners (jest, pytest) - Development servers - Long-running processes (docker, terraform) **Bash mode with `!` prefix:** ```bash # Run bash commands directly without Claude interpretation ! npm test ! git status ! ls -la ``` **Disable background tasks:** ```bash export CLAUDE_CODE_DISABLE_BACKGROUND_TASKS=1 ``` --- <h2 id="remote-sessions">Remote Sessions</h2> > [!Note] > **For subscribers: Use `--remote` to start tasks on claude.ai and `--teleport` to resume them locally.** **Start a remote session:** ```bash # Create a new web session on claude.ai with task description claude --remote "Fix the login bug" ``` **Resume a remote session:** ```bash # Resume a web session in your local terminal claude --teleport # Or use the slash command /teleport ``` --- <h2 id="sub-agents">Sub Agents</h2> > Sub‑Agents are purpose‑built helpers with their **own prompts, tools, and isolated context windows**. Treat this like a "mixture‑of‑experts" you **compose** per repo. <h3 id="built-in-subagents">Built-in Subagents</h3> Claude Code includes built-in subagents that Claude automatically uses when appropriate: | Subagent | Model | Tools | Purpose | | :------------------ | :----------- | :-------- | :------------------------------------------------ | | **Explore** | Haiku (fast) | Read-only | File discovery, code search, codebase exploration | | **Plan** | Configurable | Read-only | Planning complex changes without making edits | | **General-purpose** | Default | Inherited | General task delegation | > Claude delegates to **Explore** when it needs to search or understand a codebase without making changes, keeping exploration results out of your main conversation context. **When to use subagents:** > - You need high signal responses (plans, reviews, diffs) without side quests. > - You want version‑controlled prompts and tool policies alongside the codebase. > - You work in PR‑driven teams and want scoped edits by role. > - The task produces verbose output you don't need in your main context. <h3 id="each-sub-agent-has-its-own-context">Each Sub‑Agent Has Its Own Context</h3> **Design rules for your lineup** > - Define **one clear responsibility** per agent. > - Keep the **minimum** tool set needed for that role. > - Prefer **read‑only** agents for analysis/review tasks. > - Give edit powers to as few agents as possible. <img width="700" height="160" alt="image" src="https://github.com/user-attachments/assets/42767417-20aa-4bd4-aaf2-cfa0e515b54b" /> _Caption: Agents selection UI in the terminal._ <h3 id="configure-agents">Configure Agents</h3> > Keep agents **in the project** so they're versioned with the repo and evolve via PRs. <h3 id="agents-quick-start">Quick start</h3> > Update CLI and open the agents panel ```bash claude update /agents ``` <h3 id="agent-scopes">Subagent Scopes</h3> | Location | Scope | Priority | | :--------------------------- | :---------------------- | :---------- | | `--agents` CLI flag | Current session only | 1 (highest) | | `.claude/agents/` | Current project | 2 | | `~/.claude/agents/` | All your projects | 3 | | Plugin's `agents/` directory | Where plugin is enabled | 4 (lowest) | <h3 id="define-agents-via-cli">Define Agents via CLI</h3> ```bash # Define custom subagents dynamically via JSON claude --agents '{ "code-reviewer": { "description": "Expert code reviewer. Use proactively after code changes.", "prompt": "You are a senior code reviewer. Focus on code quality, security, and best practices.", "tools": ["Read", "Grep", "Glob", "Bash"], "model": "sonnet" }, "debugger": { "description": "Debugging specialist for errors and test failures.", "prompt": "You are an expert debugger. Analyze errors, identify root causes, and provide fixes." } }' ``` <h3 id="create-your-core-agents">Create your core agents</h3> > - **planner** (read‑only): turns features/issues into small, testable tasks; outputs a task list or plan.md. > - **codegen** (edit‑capable): implements tasks; limited to `src/` + `tests/`. > - **tester** (read‑only or patch‑only): writes _one_ failing test or a minimal repro. > - **reviewer** (read‑only): leaves structured review comments; never edits. > - **docs** (edit‑capable): updates `README.md`/`docs/` only. **\*Policy** tip: Prefer **patch output** for edit‑capable agents so changes land through your normal Git workflow.\* <img width="700" height="173" alt="image" src="https://github.com/user-attachments/assets/84bc80de-35b8-4ef7-9b27-f74f7d4a51f9" /> _Caption: Choose only the tools an agent truly needs (e.g., advisory vs editing access)._ <h3 id="example-prompts">Example prompts</h3> > Keep prompts short, testable, and repo‑specific. Check them into `agents/`: <img width="700" height="217" alt="image" src="https://github.com/user-attachments/assets/b4f92591-ff5c-4775-aec2-051f145b9616" /> _Caption: Example prompt for a **test‑coverage‑analyzer** agent._ **tester.prompt.md (sample)** ``` Role: Write a single, focused failing test for the specific scenario I describe. Scope: Only create/modify tests under tests/. Do not change src/. Output: A brief rationale + a unified diff or patch. If the scenario is unclear, ask exactly one clarifying question. ``` <h3 id="expected-output">Expected output</h3> > Your tester agent should produce a small diff or patch plus a short rationale: <img width="700" height="273" alt="image" src="https://github.com/user-attachments/assets/839151ce-02c9-4283-a53b-9dd105802ada" /> _Caption: Example response from the **test‑coverage‑analyzer** agent._ <h3 id="subagent-frontmatter">Subagent Frontmatter Fields</h3> Subagent files use YAML frontmatter for configuration: ```markdown --- name: code-reviewer description: Reviews code for quality and best practices tools: Read, Glob, Grep disallowedTools: Write, Edit model: sonnet permissionMode: default skills: - api-conventions --- You are a code reviewer. Analyze the code and provide feedback. ``` | Field | Required | Description | | :---------------- | :------- | :------------------------------------------------------------------ | | `name` | Yes | Unique identifier (lowercase, hyphens) | | `description` | Yes | When Claude should delegate to this subagent | | `tools` | No | Tools the subagent can use (inherits all if omitted) | | `disallowedTools` | No | Tools to deny, removed from inherited or specified list | | `model` | No | Model: `sonnet`, `opus`, `haiku`, or `inherit` (default: sonnet) | | `permissionMode` | No | `default`, `acceptEdits`, `dontAsk`, `bypassPermissions`, or `plan` | | `skills` | No | Skills to preload into the subagent's context | | `hooks` | No | Lifecycle hooks scoped to this subagent | | `memory` | No | Persistent memory scope: `user`, `project`, or `local` | <h3 id="why-this-shift-matters">Why This Shift Matters</h3> **Operational benefits** > - **Less context switching:** you stay in one mental mode; agents do the rest. > - **Cleaner PRs:** narrow prompts + limited tools → smaller, reviewable diffs. > - **Fewer regressions:** tester/reviewer agents catch gaps before merge. > - **Repeatability:** prompts + policies live in the repo and travel with branches. **Security & governance** > - Limit write access by path (e.g., `src/`, `tests/`, `docs/`). > - Favor read‑only analysis for high‑risk areas. > - Log/commit assistant outputs as patches for auditability. <h3 id="a-mindset-shift">A Mindset Shift</h3> **Do** > - Treat agents as teammates with job descriptions. > - Start read‑only; grant write access _last_. > - Keep prompts in version control and iterate via PR. **Don't** > - Ask one agent to plan, code, and test in a single turn. > - Give blanket write permissions. > - Accept multi‑file diffs when you asked for one test. --- <h2 id="agent-teams">Agent Teams (Research Preview)</h2> > [!Note] > **Agent Teams is an experimental feature enabling multiple Claude instances to work in parallel on a shared codebase autonomously.** **Enable Agent Teams:** ```bash export CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1 ``` **Key Concepts:** - Multiple Claude instances run in parallel on the same codebase - Each agent can specialize in different tasks (debugging, documentation, testing, etc.) - Agents communicate through git-based synchronization - Enables autonomous, long-running development workflows **Case Study: C Compiler Built by Agent Teams** Anthropic's research team demonstrated agent teams by tasking 16 parallel Claude instances to build a C compiler from scratch. Key results: | Metric | Value | |:-------|:------| | **Claude Sessions** | ~2,000 | | **API Cost** | ~$20,000 | | **Lines of Code** | 100,000 | | **Capability** | Compiled Linux 6.9 on x86, ARM, RISC-V | | **Test Pass Rate** | 99% on GCC torture test suite | **Lessons for Agent Teams:** 1. **Write high-quality tests** - The task verifier must be nearly perfect 2. **Design for parallelism** - Agents should be able to work independently without blocking each other 3. **Specialize agents** - Dedicate agents to specific roles (code quality, documentation, performance) 4. **Maintain context files** - Keep READMEs and progress files updated for agent orientation > Read the full case study: [Building a C Compiler with Parallel Claudes](https://www.anthropic.com/engineering/building-c-compiler) --- <h2 id="skills">Skills (Custom Slash Commands)</h2> > [!Note] > **Skills extend what Claude can do. Create a `SKILL.md` file with instructions, and Claude adds it to its toolkit. Claude uses skills when relevant, or you can invoke one directly with `/skill-name`.** <h3 id="skill-locations">Skill Locations</h3> | Location | Scope | Description | | :--------------------------------------- | :------- | :-------------------------------------------- | | `~/.claude/skills/<skill-name>/SKILL.md` | Personal | All your projects | | `.claude/skills/<skill-name>/SKILL.md` | Project | This project only (commit to version control) | | `<plugin>/skills/<skill-name>/SKILL.md` | Plugin | Where plugin is enabled | > Project skills override personal skills with the same name. Files in `.claude/commands/` still work and support the same frontmatter. <h3 id="create-skill">Create a Skill</h3> ```bash # Create skill directory mkdir -p ~/.claude/skills/explain-code ``` Create `~/.claude/skills/explain-code/SKILL.md`: ```markdown --- name: explain-code description: Explains code with visual diagrams and analogies. Use when explaining how code works. --- When explaining code, always include: 1. **Start with an analogy**: Compare the code to something from everyday life 2. **Draw a diagram**: Use ASCII art to show the flow, structure, or relationships 3. **Walk through the code**: Explain step-by-step what happens 4. **Highlight a gotcha**: What's a common mistake or misconception? ``` **Use the skill:** ```bash # Let Claude invoke automatically How does this code work? # Or invoke directly /explain-code src/auth/login.ts ``` <h3 id="skill-frontmatter">Skill Frontmatter Fields</h3> | Field | Required | Description | | :------------------------- | :---------- | :---------------------------------------------------------- | | `name` | No | Display name for the skill (uses directory name if omitted) | | `description` | Recommended | What the skill does and when to use it | | `argument-hint` | No | Hint shown during autocomplete (e.g., `[filename]`) | | `disable-model-invocation` | No | Set `true` to prevent Claude from auto-invoking | | `user-invocable` | No | Set `false` to hide from / menu | | `allowed-tools` | No | Tools Claude can use without asking permission | | `model` | No | Model to use when this skill is active | | `context` | No | Set to `fork` to run in a forked subagent context | | `agent` | No | Which subagent to use when `context: fork` is set | | `hooks` | No | Hooks scoped to this skill's lifecycle | <h3 id="skill-arguments">Pass Arguments to Skills</h3> Use `$ARGUMENTS` placeholder to receive arguments: ```markdown --- name: fix-issue description: Fix a GitHub issue disable-model-invocation: true --- Fix GitHub issue $ARGUMENTS following our coding standards. 1. Read the issue description 2. Implement the fix 3. Write tests 4. Create a commit ``` **Usage:** `/fix-issue 123` <h3 id="skill-dynamic-context">Inject Dynamic Context</h3> Use `` !`command` `` syntax to run shell commands before the skill content is sent to Claude: ```markdown --- name: pr-summary description: Summarize changes in a pull request context: fork agent: Explore --- ## Pull request context - PR diff: !`gh pr diff` - PR comments: !`gh pr view --comments` - Changed files: !`gh pr diff --name-only` ## Your task Summarize this pull request... ``` <h3 id="skill-subagent">Run Skills in a Subagent</h3> Add `context: fork` to run a skill in isolation: ```markdown --- name: deep-research description: Research a topic thoroughly context: fork agent: Explore --- Research $ARGUMENTS thoroughly: 1. Find relevant files using Glob and Grep 2. Read and analyze the code 3. Summarize findings with specific file references ``` > The `agent` field can be `Explore`, `Plan`, `general-purpose`, or any custom subagent from `.claude/agents/`. --- <h2 id="insights">Claude Code Insights</h2> > [!Note] > **The `/insights` command generates an interactive HTML report analyzing your coding habits from the past 30 days.** **Run Insights:** ```bash # In Claude Code terminal /insights # Open the generated report start ~/.claude/usage-data/report.html # Windows open ~/.claude/usage-data/report.html # Mac xdg-open ~/.claude/usage-data/report.html # Linux ``` **How It Works:** 1. **Session Collection** - Pulls session logs from `~/.claude/projects/`, filters agent sub-sessions and short sessions 2. **Metadata Extraction** - Extracts duration, token usage, tools used, languages detected, git activity 3. **Facet Extraction** - Uses Haiku model to analyze transcripts and identify goals, satisfaction signals, friction points 4. **Report Generation** - Creates interactive HTML report with personalized suggestions **Report Sections:** | Section | Description | |:--------|:------------| | **What's Working** | Your strengths and successful patterns | | **What's Hindering** | Where Claude struggled or where you caused friction | | **Friction Analysis** | Breakdown of problem areas with specific examples | | **Stats Dashboard** | Tool usage, language breakdown, coding time distribution | | **Quick Wins** | Copy-paste suggestions for CLAUDE.md improvements | | **Features to Try** | Personalized recommendations (skills, hooks, headless mode) | > Everything runs locally using the Anthropic API. Session data stays on your machine. --- <h2 id="mcp-integration">MCP Integration</h2> <h3 id="understanding-mcp-model-context-protocol">Understanding MCP (Model Context Protocol)</h3> #### What is MCP? > MCP extends Claude's capabilities by connecting to external services, databases, APIs, and tools (filesystem, Puppeteer, GitHub, Context7 etc...) ###### **MCP Architecture:** ``` Claude Code ←→ MCP Protocol ←→ MCP Servers ←→ External Services ``` <h3 id="mcp-setup--configuration">MCP Setup & Configuration</h3> ###### Basic MCP Commands ```bash claude mcp # Interactive MCP configuration claude mcp list # List configured servers claude mcp add <name> <cmd> # Add new server claude mcp remove <name> # Remove server ``` ###### MCP Configuration File Location ```bash ~/.claude.json # Global File `.mcp.json` # Project-scoped servers are stored in a File at your project's root directory ``` ## Quick Start > **If you're in a hurry, here's the fastest way to add:** ```bash # Add file system access (most commonly used) claude mcp add filesystem -s user -- npx -y @modelcontextprotocol/server-filesystem ~/Documents ~/Desktop # Verify if successful claude mcp list ``` > **Responce if it worked like it should:** > <img width="868" height="192" alt="image" src="https://github.com/user-attachments/assets/8e7b23c7-ccfb-49aa-9203-e37f07c2514e" /> </td></table> ## Additional Methods: <table><td> ### 1. Command Line Addition > **Claude Code provides simple command line tools to add MCP servers:** ```bash # Basic syntax claude mcp add <name> <command> [parameters...] # Actual example: Add local file system access claude mcp add my-filesystem -- npx -y @modelcontextprotocol/server-filesystem ~/Documents # Example with environment variables claude mcp add api-server -e API_KEY=your-key-here -- /path/to/server ``` **OAuth for MCP Servers:** ```bash # Add MCP server with pre-configured OAuth credentials claude mcp add <name> --client-id <id> --client-secret <secret> -- <cmd> ``` > Some MCP servers (e.g., Slack) don't support Dynamic Client Registration and require pre-configured OAuth credentials. </td></table> <table><td> ### 2. Direct Configuration File Editing > Many developers find CLI wizards too cumbersome, especially when you have to restart if you make a mistake. > > Direct configuration file editing is more efficient: **1. Find configuration file location:** - macOS/Linux: `~/.claude.json` - Windows: `%USERPROFILE%\.claude.json` **2. Edit configuration file:** ```json { "mcpServers": { "filesystem": { "type": "stdio", "command": "npx", "args": [ "-y", "@modelcontextprotocol/server-filesystem", "/Users/username/Documents" ], "env": {} }, "github": { "type": "stdio", "command": "npx", "args": ["-y", "@modelcontextprotocol/server-github"], "env": { "GITHUB_TOKEN": "your-github-token" } } } } ``` **3. Restart Claude Code to take effect** </td></table> <table><td> ### 3. Project-level Configuration (Recommended for team collaboration) > If you want team members to all use the same MCP configuration: ```bash # Add project-level MCP server claude mcp add shared-tools -s project -- npx -y @your-team/mcp-tools ``` **This will create a `.mcp.json` file in the project root directory:** ```json { "mcpServers": { "shared-tools": { "command": "npx", "args": ["-y", "@your-team/mcp-tools"], "env": {} } } } ``` </td></table> ## MCP Server Scope Detailed Understanding scope is crucial to avoid "server not found" errors: ### 1. Local Scope (Default) - Only available in current directory - Configuration stored in the projects section of `~/.claude.json` - Suitable for: Personal project-specific tools ### 2. User Scope (Global) - Available in all projects - Added using `-s user` flag - Suitable for: Common tools like file systems, database clients ### 3. Project Scope (Team shared) - Shared through `.mcp.json` file - Added using `-s project` flag - Suitable for: Team-shared project-specific tools ## Practical MCP Server Recommendations > **Here's the most worthwhile MCP server list to install:** ### 1. File System Access ```bash claude mcp add filesystem -s user -- npx -y @modelcontextprotocol/server-filesystem ~/Documents ~/Projects ~/Desktop ``` Use: Let Claude directly read and write files, modify code ### 2. GitHub Integration ```bash claude mcp add github -s user -e GITHUB_TOKEN=your-token -- npx -y @modelcontextprotocol/server-github ``` Use: Manage issues, PRs, code reviews ### 3. Web Browser Control ```bash claude mcp add puppeteer -s user -- npx -y @modelcontextprotocol/server-puppeteer ``` Use: Automated web operations, crawling, testing ### 4. Database Connection (PostgreSQL) ```bash claude mcp add postgres -s user -e DATABASE_URL=your-db-url -- npx -y @modelcontextprotocol/server-postgres ``` Use: Directly query and manipulate databases ### 5. Fetch Tool (API Calls) ```bash claude mcp add fetch -s user -- npx -y @kazuph/mcp-fetch ``` Use: Call various REST APIs ### 6. Search Engine ```bash claude mcp add search -s user -e BRAVE_API_KEY=your-key -- npx -y @modelcontextprotocol/server-brave-search ``` Use: Search for latest information ### 7. Slack Integration ```bash claude mcp add slack -s user -e SLACK_TOKEN=your-token -- npx -y @modelcontextprotocol/server-slack ``` Use: Send messages, manage channels ### 8. Time Management ```bash claude mcp add time -s user -- npx -y @modelcontextprotocol/server-time ``` Use: Time zone conversion, date calculation ### 9. Memory Storage ```bash claude mcp add memory -s user -- npx -y @modelcontextprotocol/server-memory ``` Use: Save information across conversations ### 10. Sequential Thinking (Thought Chain) ```bash claude mcp add thinking -s user -- npx -y @modelcontextprotocol/server-sequential-thinking ``` Use: Step-by-step thinking for complex problems ## Common Errors and Solutions ### Error 1: Tool Name Validation Failed ``` API Error 400: "tools.11.custom.name: String should match pattern '^[a-zA-Z0-9_-]{1,64}$'" ``` **Solution**: - Ensure server name only contains letters, numbers, underscores and hyphens - Name length should not exceed 64 characters - Don't use special characters or spaces ### Error 2: MCP Server Not Found ``` MCP server 'my-server' not found ``` **Solution**: 1. Check if scope settings are correct 2. Run `claude mcp list` to confirm server has been added 3. Ensure you're in the correct directory (for local scope) 4. Restart Claude Code ### Error 3: Protocol Version Error ``` "protocolVersion": "Required" ``` **Solution**: This is a known bug in Claude Code, temporary solutions: 1. Use wrapper scripts 2. Ensure MCP server returns correct protocol version 3. Update to latest version of Claude Code ### Error 4: Windows Path Issues ``` Error: Cannot find module 'C:UsersusernameDocuments' ``` **Solution**: Windows paths need to use forward slashes or double backslashes: ```bash # Wrong claude mcp add fs -- npx -y @modelcontextprotocol/server-filesystem C:\Users\username\Documents # Correct claude mcp add fs -- npx -y @modelcontextprotocol/server-filesystem C:/Users/username/Documents # or claude mcp add fs -- npx -y @modelcontextprotocol/server-filesystem C:\\Users\\username\\Documents ``` ### Error 5: Permission Issues ``` Permission denied ``` **Solution**: 1. macOS/Linux: Use `sudo` (not recommended) or modify file permissions 2. Windows: Run as administrator 3. Best method: Install MCP servers in user directory ## Debugging Techniques When encountering problems, these debugging methods can help you quickly locate issues: ### 1. Enable Debug Mode ```bash claude --mcp-debug ``` ### 2. View MCP Status In Claude Code, enter: ``` /mcp ``` ### 3. View Log Files **macOS/Linux:** ```bash tail -f ~/Library/Logs/Claude/mcp*.log ``` **Windows:** ```cmd type "%APPDATA%\Claude\logs\mcp*.log" ``` ### 4. Manually Test Server ```bash # Directly run server command to see if there's output npx -y @modelcontextprotocol/server-filesystem ~/Documents ``` ## Special Notes for International Users ### 1. Non-English Path Issues Avoid using non-English characters in paths: ```bash # Avoid claude mcp add fs -- npx -y @modelcontextprotocol/server-filesystem ~/文档 # Recommended claude mcp add fs -- npx -y @modelcontextprotocol/server-filesystem ~/Documents ``` ### 2. Proxy Configuration If you're using a proxy: ```bash # Set npm proxy npm config set proxy http://your-proxy:port npm config set https-proxy http://your-proxy:port # Then add MCP server claude mcp add ... ``` ### 3. Mirror Sources Use mirror sources to accelerate downloads: ```bash # Temporary use claude mcp add fs -- npx -y --registry=https://registry.npmjs.org @modelcontextprotocol/server-filesystem ~/Documents # Or permanent setting npm config set registry https://registry.npmjs.org ``` ## Best Practice Recommendations 1. **Add as needed**: Don't add too many MCP servers at once, it will affect performance 2. **Regular cleanup**: Use `claude mcp remove <name>` to delete unused servers 3. **Security first**: Only add trusted MCP servers, especially those requiring network access 4. **Backup configuration**: Regularly backup `~/.claude.json` file 5. **Team collaboration**: Use project scope to share common configurations ## Advanced Techniques ### 1. Create Custom MCP Server If existing MCP servers can't meet your needs, you can create your own: ```javascript // my-mcp-server.js import { Server } from "@modelcontextprotocol/sdk"; const server = new Server({ name: "my-custom-server", version: "1.0.0", }); server.setRequestHandler("tools/list", async () => { return { tools: [ { name: "my_custom_tool", description: "Custom tool", inputSchema: { type: "object", properties: { input: { type: "string" }, }, }, }, ], }; }); server.start(); ``` ### 2. Batch Configuration Script Create a script to configure all common MCP servers at once: ```bash #!/bin/bash # setup-mcp.sh echo "Configuring common MCP servers..." # File system claude mcp add filesystem -s user -- npx -y @modelcontextprotocol/server-filesystem ~/Documents ~/Projects # GitHub read -p "Enter GitHub Token: " github_token claude mcp add github -s user -e GITHUB_TOKEN=$github_token -- npx -y @modelcontextprotocol/server-github # Other servers... echo "MCP servers configured successfully!" ``` <h3 id="popular-mcp-servers">Popular MCP Servers</h3> #### Development Tools ```bash # npm install -g git-mcp-server # claude mcp add git "git-mcp-server" # claude mcp add github "github-mcp-server --token $GITHUB_TOKEN" ``` #### Database Integration ```bash npm install -g postgres-mcp-server npm install -g mysql-mcp-server npm install -g sqlite-mcp-server # Setup examples may look like this: # export POSTGRES_URL="postgresql://user:password@localhost:5432/mydb" # claude mcp add postgres "postgres-mcp-server --url $POSTGRES_URL" ``` #### MCP Tool Permissions ```bash # Allow specific MCP tools claude --allowedTools "mcp__git__commit,mcp__git__push" # Allow all tools from specific server claude --allowedTools "mcp__postgres__*" # Combined with built-in tools claude --allowedTools "Edit,View,mcp__git__*" ``` <h2 id="hooks-system">Hooks System</h2> > This page provides reference documentation for implementing hooks in Claude Code. <Tip> For a quickstart guide with examples, see [Get started with Claude Code hooks](/en/docs/claude-code/hooks-guide). </Tip> <h3 id="hooks-configuration">Configuration</h3> Claude Code hooks are configured in your [settings files](/en/docs/claude-code/settings): - `~/.claude/settings.json` - User settings - `.claude/settings.json` - Project settings - `.claude/settings.local.json` - Local project settings (not committed) - Enterprise managed policy settings #### Structure Hooks are organized by matchers, where each matcher can have multiple hooks: ```json { "hooks": { "EventName": [ { "matcher": "ToolPattern", "hooks": [ { "type": "command", "command": "your-command-here" } ] } ] } } ``` - **matcher**: Pattern to match tool names, case-sensitive (only applicable for `PreToolUse` and `PostToolUse`) - Simple strings match exactly: `Write` matches only the Write tool - Supports regex: `Edit|Write` or `Notebook.*` - Use `*` to match all tools. You can also use empty string (`""`) or leave `matcher` blank. - **hooks**: Array of commands to execute when the pattern matches - `type`: Currently only `"command"` is supported - `command`: The bash command to execute (can use `$CLAUDE_PROJECT_DIR` environment variable) - `timeout`: (Optional) How long a command should run, in seconds, before canceling that specific command. For events like `UserPromptSubmit`, `Notification`, `Stop`, and `SubagentStop` that don't use matchers, you can omit the matcher field: ```json { "hooks": { "UserPromptSubmit": [ { "hooks": [ { "type": "command", "command": "/path/to/prompt-validator.py" } ] } ] } } ``` #### Project-Specific Hook Scripts You can use the environment variable `CLAUDE_PROJECT_DIR` (only available when Claude Code spawns the hook command) to reference scripts stored in your project, ensuring they work regardless of Claude's current directory: ```json { "hooks": { "PostToolUse": [ { "matcher": "Write|Edit", "hooks": [ { "type": "command", "command": "$CLAUDE_PROJECT_DIR/.claude/hooks/check-style.sh" } ] } ] } } ``` <h3 id="hook-events">Hook Events</h3> #### PreToolUse Runs after Claude creates tool parameters and before processing the tool call. **Common matchers:** - `Task` - Subagent tasks (see [subagents documentation](/en/docs/claude-code/sub-agents)) - `Bash` - Shell commands - `Glob` - File pattern matching - `Grep` - Content search - `Read` - File reading - `Edit`, `MultiEdit` - File editing - `Write` - File writing - `WebFetch`, `WebSearch` - Web operations #### PostToolUse Runs immediately after a tool completes successfully. Recognizes the same matcher values as PreToolUse. #### Notification Runs when Claude Code sends notifications. Notifications are sent when: 1. Claude needs your permission to use a tool. Example: "Claude needs your permission to use Bash" 2. The prompt input has been idle for at least 60 seconds. "Claude is waiting for your input" #### UserPromptSubmit Runs when the user submits a prompt, before Claude processes it. This allows you to add additional context based on the prompt/conversation, validate prompts, or block certain types of prompts. #### Stop Runs when the main Claude Code agent has finished responding. Does not run if the stoppage occurred due to a user interrupt. #### SubagentStop Runs when a Claude Code subagent (Task tool call) has finished responding. #### TeammateIdle Triggered when an agent teammate becomes idle (multi-agent workflows). #### TaskCompleted Triggered when a background task completes (multi-agent workflows). #### PreCompact Runs before Claude Code is about to run a compact operation. **Matchers:** - `manual` - Invoked from `/compact` - `auto` - Invoked from auto-compact (due to full context window) #### SessionStart Runs when Claude Code starts a new session or resumes an existing session (which currently does start a new session under the hood). Useful for loading in development context like existing issues or recent changes to your codebase. **Matchers:** - `startup` - Invoked from startup - `resume` - Invoked from `--resume`, `--continue`, or `/resume` - `clear` - Invoked from `/clear` <h3 id="hook-input">Hook Input</h3> Hooks receive JSON data via stdin containing session information and event-specific data: ```typescript { // Common fields session_id: string transcript_path: string // Path to conversation JSON cwd: string // The current working directory when the hook is invoked // Event-specific fields hook_event_name: string ... } ``` #### PreToolUse Input The exact schema for `tool_input` depends on the tool. ```json { "session_id": "abc123", "transcript_path": "/Users/.../.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl", "cwd": "/Users/...", "hook_event_name": "PreToolUse", "tool_name": "Write", "tool_input": { "file_path": "/path/to/file.txt", "content": "file content" } } ``` #### PostToolUse Input The exact schema for `tool_input` and `tool_response` depends on the tool. ```json { "session_id": "abc123", "transcript_path": "/Users/.../.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl", "cwd": "/Users/...", "hook_event_name": "PostToolUse", "tool_name": "Write", "tool_input": { "file_path": "/path/to/file.txt", "content": "file content" }, "tool_response": { "filePath": "/path/to/file.txt", "success": true } } ``` #### Notification Input ```json { "session_id": "abc123", "transcript_path": "/Users/.../.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl", "cwd": "/Users/...", "hook_event_name": "Notification", "message": "Task completed successfully" } ``` #### UserPromptSubmit Input ```json { "session_id": "abc123", "transcript_path": "/Users/.../.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl", "cwd": "/Users/...", "hook_event_name": "UserPromptSubmit", "prompt": "Write a function to calculate the factorial of a number" } ``` #### Stop and SubagentStop Input `stop_hook_active` is true when Claude Code is already continuing as a result of a stop hook. Check this value or process the transcript to prevent Claude Code from running indefinitely. ```json { "session_id": "abc123", "transcript_path": "~/.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl", "hook_event_name": "Stop", "stop_hook_active": true } ``` #### PreCompact Input For `manual`, `custom_instructions` comes from what the user passes into `/compact`. For `auto`, `custom_instructions` is empty. ```json { "session_id": "abc123", "transcript_path": "~/.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl", "hook_event_name": "PreCompact", "trigger": "manual", "custom_instructions": "" } ``` #### SessionStart Input ```json { "session_id": "abc123", "transcript_path": "~/.claude/projects/.../00893aaf-19fa-41d2-8238-13269b9b3ca0.jsonl", "hook_event_name": "SessionStart", "source": "startup" } ``` <h3 id="hook-output">Hook Output</h3> There are two ways for hooks to return output back to Claude Code. The output communicates whether to block and any feedback that should be shown to Claude and the user. #### Simple: Exit Code Hooks communicate status through exit codes, stdout, and stderr: - **Exit code 0**: Success. `stdout` is shown to the user in transcript mode (CTRL-R), except for `UserPromptSubmit` and `SessionStart`, where stdout is added to the context. - **Exit code 2**: Blocking error. `stderr` is fed back to Claude to process automatically. See per-hook-event behavior below. - **Other exit codes**: Non-blocking error. `stderr` is shown to the user and execution continues. <Warning> Reminder: Claude Code does not see stdout if the exit code is 0, except for the `UserPromptSubmit` hook where stdout is injected as context. </Warning> ##### Exit Code 2 Behavior | Hook Event | Behavior | | ------------------ | ------------------------------------------------------------------ | | `PreToolUse` | Blocks the tool call, shows stderr to Claude | | `PostToolUse` | Shows stderr to Claude (tool already ran) | | `Notification` | N/A, shows stderr to user only | | `UserPromptSubmit` | Blocks prompt processing, erases prompt, shows stderr to user only | | `Stop` | Blocks stoppage, shows stderr to Claude | | `SubagentStop` | Blocks stoppage, shows stderr to Claude subagent | | `PreCompact` | N/A, shows stderr to user only | | `SessionStart` | N/A, shows stderr to user only | #### Advanced: JSON Output Hooks can return structured JSON in `stdout` for more sophisticated control: ##### Common JSON Fields All hook types can include these optional fields: ```json { "continue": true, // Whether Claude should continue after hook execution (default: true) "stopReason": "string" // Message shown when continue is false "suppressOutput": true, // Hide stdout from transcript mode (default: false) } ``` If `continue` is false, Claude stops processing after the hooks run. - For `PreToolUse`, this is different from `"permissionDecision": "deny"`, which only blocks a specific tool call and provides automatic feedback to Claude. - For `PostToolUse`, this is different from `"decision": "block"`, which provides automated feedback to Claude. - For `UserPromptSubmit`, this prevents the prompt from being processed. - For `Stop` and `SubagentStop`, this takes precedence over any `"decision": "block"` output. - In all cases, `"continue" = false` takes precedence over any `"decision": "block"` output. `stopReason` accompanies `continue` with a reason shown to the user, not shown to Claude. ##### `PreToolUse` Decision Control `PreToolUse` hooks can control whether a tool call proceeds. - `"allow"` bypasses the permission system. `permissionDecisionReason` is shown to the user but not to Claude. (_Deprecated `"approve"` value + `reason` has the same behavior._) - `"deny"` prevents the tool call from executing. `permissionDecisionReason` is shown to Claude. (_`"block"` value + `reason` has the same behavior._) - `"ask"` asks the user to confirm the tool call in the UI. `permissionDecisionReason` is shown to the user but not to Claude. ```json { "hookSpecificOutput": { "hookEventName": "PreToolUse", "permissionDecision": "allow" | "deny" | "ask", "permissionDecisionReason": "My reason here (shown to user)" }, "decision": "approve" | "block" | undefined, // Deprecated for PreToolUse but still supported "reason": "Explanation for decision" // Deprecated for PreToolUse but still supported } ``` ##### `PostToolUse` Decision Control `PostToolUse` hooks can control whether a tool call proceeds. - `"block"` automatically prompts Claude with `reason`. - `undefined` does nothing. `reason` is ignored. ```json { "decision": "block" | undefined, "reason": "Explanation for decision" } ``` ##### `UserPromptSubmit` Decision Control `UserPromptSubmit` hooks can control whether a user prompt is processed. - `"block"` prevents the prompt from being processed. The submitted prompt is erased from context. `"reason"` is shown to the user but not added to context. - `undefined` allows the prompt to proceed normally. `"reason"` is ignored. - `"hookSpecificOutput.additionalContext"` adds the string to the context if not blocked. ```json { "decision": "block" | undefined, "reason": "Explanation for decision", "hookSpecificOutput": { "hookEventName": "UserPromptSubmit", "additionalContext": "My additional context here" } } ``` ##### `Stop`/`SubagentStop` Decision Control `Stop` and `SubagentStop` hooks can control whether Claude must continue. - `"block"` prevents Claude from stopping. You must populate `reason` for Claude to know how to proceed. - `undefined` allows Claude to stop. `reason` is ignored. ```json { "decision": "block" | undefined, "reason": "Must be provided when Claude is blocked from stopping" } ``` ##### `SessionStart` Decision Control `SessionStart` hooks allow you to load in context at the start of a session. - `"hookSpecificOutput.additionalContext"` adds the string to the context. ```json { "hookSpecificOutput": { "hookEventName": "SessionStart", "additionalContext": "My additional context here" } } ``` ##### Exit Code Example: Bash Command Validation ```python #!/usr/bin/env python3 import json import re import sys # Define validation rules as a list of (regex pattern, message) tuples VALIDATION_RULES = [ ( r"\bgrep\b(?!.*\|)", "Use 'rg' (ripgrep) instead of 'grep' for better performance and features", ), ( r"\bfind\s+\S+\s+-name\b", "Use 'rg --files | rg pattern' or 'rg --files -g pattern' instead of 'find -name' for better performance", ), ] def validate_command(command: str) -> list[str]: issues = [] for pattern, message in VALIDATION_RULES: if re.search(pattern, command): issues.append(message) return issues try: input_data = json.load(sys.stdin) except json.JSONDecodeError as e: print(f"Error: Invalid JSON input: {e}", file=sys.stderr) sys.exit(1) tool_name = input_data.get("tool_name", "") tool_input = input_data.get("tool_input", {}) command = tool_input.get("command", "") if tool_name != "Bash" or not command: sys.exit(1) # Validate the command issues = validate_command(command) if issues: for message in issues: print(f"• {message}", file=sys.stderr) # Exit code 2 blocks tool call and shows stderr to Claude sys.exit(2) ``` ##### JSON Output Example: UserPromptSubmit to Add Context and Validation <Note> For `UserPromptSubmit` hooks, you can inject context using either method: - Exit code 0 with stdout: Claude sees the context (special case for `UserPromptSubmit`) - JSON output: Provides more control over the behavior </Note> ```python #!/usr/bin/env python3 import json import sys import re import datetime # Load input from stdin try: input_data = json.load(sys.stdin) except json.JSONDecodeError as e: print(f"Error: Invalid JSON input: {e}", file=sys.stderr) sys.exit(1) prompt = input_data.get("prompt", "") # Check for sensitive patterns sensitive_patterns = [ (r"(?i)\b(password|secret|key|token)\s*[:=]", "Prompt contains potential secrets"), ] for pattern, message in sensitive_patterns: if re.search(pattern, prompt): # Use JSON output to block with a specific reason output = { "decision": "block", "reason": f"Security policy violation: {message}. Please rephrase your request without sensitive information." } print(json.dumps(output)) sys.exit(0) # Add current time to context context = f"Current time: {datetime.datetime.now()}" print(context) """ The following is also equivalent: print(json.dumps({ "hookSpecificOutput": { "hookEventName": "UserPromptSubmit", "additionalContext": context, }, })) """ # Allow the prompt to proceed with the additional context sys.exit(0) ``` ##### JSON Output Example: PreToolUse with Approval ```python #!/usr/bin/env python3 import json import sys # Load input from stdin try: input_data = json.load(sys.stdin) except json.JSONDecodeError as e: print(f"Error: Invalid JSON input: {e}", file=sys.stderr) sys.exit(1) tool_name = input_data.get("tool_name", "") tool_input = input_data.get("tool_input", {}) # Example: Auto-approve file reads for documentation files if tool_name == "Read": file_path = tool_input.get("file_path", "") if file_path.endswith((".md", ".mdx", ".txt", ".json")): # Use JSON output to auto-approve the tool call output = { "decision": "approve", "reason": "Documentation file auto-approved", "suppressOutput": True # Don't show in transcript mode } print(json.dumps(output)) sys.exit(0) # For other cases, let the normal permission flow proceed sys.exit(0) ``` <h3 id="working-with-mcp-tools">Working with MCP Tools</h3> Claude Code hooks work seamlessly with [Model Context Protocol (MCP) tools](/en/docs/claude-code/mcp). When MCP servers provide tools, they appear with a special naming pattern that you can match in your hooks. #### MCP Tool Naming MCP tools follow the pattern `mcp__<server>__<tool>`, for example: - `mcp__memory__create_entities` - Memory server's create entities tool - `mcp__filesystem__read_file` - Filesystem server's read file tool - `mcp__github__search_repositories` - GitHub server's search tool #### Configuring Hooks for MCP Tools You can target specific MCP tools or entire MCP servers: ```json { "hooks": { "PreToolUse": [ { "matcher": "mcp__memory__.*", "hooks": [ { "type": "command", "command": "echo 'Memory operation initiated' >> ~/mcp-operations.log" } ] }, { "matcher": "mcp__.*__write.*", "hooks": [ { "type": "command", "command": "/home/user/scripts/validate-mcp-write.py" } ] } ] } } ``` <h3 id="hooks-examples">Examples</h3> <Tip> For practical examples including code formatting, notifications, and file protection, see [More Examples](/en/docs/claude-code/hooks-guide#more-examples) in the get started guide. </Tip> <h3 id="security-considerations">Security Considerations</h3> #### Disclaimer **USE AT YOUR OWN RISK**: Claude Code hooks execute arbitrary shell commands on your system automatically. By using hooks, you acknowledge that: - You are solely responsible for the commands you configure - Hooks can modify, delete, or access any files your user account can access - Malicious or poorly written hooks can cause data loss or system damage - Anthropic provides no warranty and assumes no liability for any damages resulting from hook usage - You should thoroughly test hooks in a safe environment before production use Always review and understand any hook commands before adding them to your configuration. ##<h2 id="security-best-practices-main">Security Best Practices</h2> Here are some key practices for writing more secure hooks: 1. **Validate and sanitize inputs** - Never trust input data blindly 2. **Always quote shell variables** - Use `"$VAR"` not `$VAR` 3. **Block path traversal** - Check for `..` in file paths 4. **Use absolute paths** - Specify full paths for scripts (use `$CLAUDE_PROJECT_DIR` for the project path) 5. **Skip sensitive files** - Avoid `.env`, `.git/`, keys, etc. #### Configuration Safety Direct edits to hooks in settings files don't take effect immediately. Claude Code: 1. Captures a snapshot of hooks at startup 2. Uses this snapshot throughout the session 3. Warns if hooks are modified externally 4. Requires review in `/hooks` menu for changes to apply This prevents malicious hook modifications from affecting your current session. <h3 id="hook-execution-details">Hook Execution Details</h3> - **Timeout**: 60-second execution limit by default, configurable per command. - A timeout for an individual command does not affect the other commands. - **Parallelization**: All matching hooks run in parallel - **Environment**: Runs in current directory with Claude Code's environment - The `CLAUDE_PROJECT_DIR` environment variable is available and contains the absolute path to the project root directory - **Input**: JSON via stdin - **Output**: - PreToolUse/PostToolUse/Stop: Progress shown in transcript (Ctrl-R) - Notification: Logged to debug only (`--debug`) <h3 id="hooks-debugging">Debugging</h3> #### Basic Troubleshooting If your hooks aren't working: 1. **Check configuration** - Run `/hooks` to see if your hook is registered 2. **Verify syntax** - Ensure your JSON settings are valid 3. **Test commands** - Run hook commands manually first 4. **Check permissions** - Make sure scripts are executable 5. **Review logs** - Use `claude --debug` to see hook execution details Common issues: - **Quotes not escaped** - Use `\"` inside JSON strings - **Wrong matcher** - Check tool names match exactly (case-sensitive) - **Command not found** - Use full paths for scripts #### Advanced Debugging For complex hook issues: 1. **Inspect hook execution** - Use `claude --debug` to see detailed hook execution 2. **Validate JSON schemas** - Test hook input/output with external tools 3. **Check environment variables** - Verify Claude Code's environment is correct 4. **Test edge cases** - Try hooks with unusual file paths or inputs 5. **Monitor system resources** - Check for resource exhaustion during hook execution 6. **Use structured logging** - Implement logging in your hook scripts #### Debug Output Example Use `claude --debug` to see hook execution details: ``` [DEBUG] Executing hooks for PostToolUse:Write [DEBUG] Getting matching hook commands for PostToolUse with query: Write [DEBUG] Found 1 hook matchers in settings [DEBUG] Matched 1 hooks for query "Write" [DEBUG] Found 1 hook commands to execute [DEBUG] Executing hook command: <Your command> with timeout 60000ms [DEBUG] Hook command completed with status 0: <Your stdout> ``` Progress messages appear in transcript mode (Ctrl-R) showing: - Which hook is running - Command being executed - Success/failure status - Output or error messages --- <h1 id="security--permissions">Security & Permissions</h1> #### Tool Permission Patterns ```bash # Allow specific tools (read/edit files) claude --allowedTools "Edit,Read" # Allow tool categories incl. Bash (but still scoped below) claude --allowedTools "Edit,Read,Bash" # Scoped permissions (all git commands) claude --allowedTools "Bash(git:*)" # Multiple scopes (git + npm) claude --allowedTools "Bash(git:*),Bash(npm:*)" ``` <h3 id="dangerous-mode">Dangerous Mode</h3> > [!Warning] > NEVER use in Production systems, shared machines, or any systems with important data > Only use with isolated environments like a **Docker container**, using this mode can cause data loss and comprimise your system! > > `claude --dangerously-skip-permissions` <h2 id="security-best-practices-main">Security Best Practices</h2> <h3 id="start-restrictive">Start Restrictive</h3> <h3 id="protect-sensitive-data">Protect Sensitive Data</h3> - **Keep `~/.claude.json` private (`chmod 600`).** - **Prefer environment variables for API keys over plain‑text.** - Use `--strict-mcp-config` to only load MCP servers from specified config files <h1 id="automation--integration">Automation & Integration</h1> <h2 id="automation--scripting-with-claude-code">Automation & Scripting with Claude Code</h2> > GitHub Actions you can copy/paste :p 1. **Install the Claude GitHub App** on your org/repo (required for Actions to comment on PRs/issues). 2. In your repo, add a secret **`ANTHROPIC_API_KEY`** Settings → Secrets and variables → Actions → New repository secret 3. Copy the workflows below into **`.github/workflows/`**. 4. Open a **test PR** (or a new issue) to see them run. > [!TIP] > Pin Actions to a release tag (e.g. `@v1`) when you adopt them long‑term. The snippets below use branch tags for readability. <h2 id="auto-pr-review-inline-comments">Auto PR Review (inline comments)</h2> > **Creates a structured review (with inline comments) as soon as a PR opens or updates.** **File:** `.github/workflows/claude-pr-auto-review.yml` ```yaml name: Auto review PRs on: pull_request: types: [opened, synchronize, reopened, ready_for_review] permissions: contents: read pull-requests: write jobs: auto-review: runs-on: ubuntu-latest steps: - uses: actions/checkout@v4 with: fetch-depth: 1 - name: Claude PR review uses: anthropics/claude-code-action@main with: anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }} # Claude will fetch the diff and leave inline comments direct_prompt: | Review this pull request’s diff for correctness, readability, testing, performance, and DX. Prefer specific, actionable suggestions. Use inline comments where relevant. # GitHub tools permitted during the run: allowed_tools: >- mcp__github__get_pull_request_diff, mcp__github__create_pending_pull_request_review, mcp__github__add_comment_to_pending_review, mcp__github__submit_pending_pull_request_review ``` <h2 id="security-review-on-every-pr">Security Review on Every PR</h2> > **Runs a focused security scan and comments findings directly on the PR.** **File:** `.github/workflows/claude-security-review.yml` ```yaml name: Security Review on: pull_request: permissions: contents: read pull-requests: write jobs: security: runs-on: ubuntu-latest steps: - uses: actions/checkout@v4 with: ref: ${{ github.event.pull_request.head.sha || github.sha }} fetch-depth: 2 - name: Claude Code Security Review uses: anthropics/claude-code-security-review@main with: claude-api-key: ${{ secrets.ANTHROPIC_API_KEY }} comment-pr: true # Optional: # exclude-directories: "docs,examples" # claudecode-timeout: "20" # claude-model: "claude-3-5-sonnet-20240620" ``` <h2 id="issue-triage-suggest-labels--severity">Issue Triage (suggest labels & severity)</h2> > **When a new issue opens, Claude proposes labels/severity and posts a tidy triage comment. You can enable **auto‑apply labels** by flipping a single flag** **File:** `.github/workflows/claude-issue-triage.yml` ```yaml name: Claude Issue Triage on: issues: types: [opened, edited, reopened] permissions: contents: read issues: write jobs: triage: runs-on: ubuntu-latest env: CLAUDE_MODEL: claude-3-5-sonnet-20240620 steps: - name: Collect context & similar issues id: gather env: GH_TOKEN: ${{ secrets.GITHUB_TOKEN }} run: | TITLE="${{ github.event.issue.title }}" BODY="${{ github.event.issue.body }}" # naive similar search by title words Q=$(echo "$TITLE" | tr -dc '[:alnum:] ' | awk '{print $1" "$2" "$3" "$4}') gh api -X GET search/issues -f q="repo:${{ github.repository }} is:issue $Q" -f per_page=5 > similars.json echo "$TITLE" > title.txt echo "$BODY" > body.txt - name: Ask Claude for triage JSON env: ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }} run: | cat > payload.json << 'JSON' { "model": "${{ env.CLAUDE_MODEL }}", "max_tokens": 1500, "system": "You are a pragmatic triage engineer. Be specific, cautious with duplicates.", "messages": [{ "role": "user", "content": [{ "type":"text", "text":"Given the issue and similar candidates, produce STRICT JSON with keys: labels (array of strings), severity (one of: low, medium, high, critical), duplicate_url (string or empty), comment_markdown (string brief). Do not include any extra keys." }, {"type":"text","text":"Issue title:\n"}, {"type":"text","text": (include from file) }, {"type":"text","text":"\n\nIssue body:\n"}, {"type":"text","text": (include from file) }, {"type":"text","text":"\n\nSimilar issues (JSON):\n"}, {"type":"text","text": (include from file) }] }] } JSON # Inject files safely jq --arg title "$(cat title.txt)" '.messages[0].content[2].text = $title' payload.json \ | jq --arg body "$(cat body.txt)" '.messages[0].content[4].text = $body' \ | jq --arg sims "$(cat similars.json)" '.messages[0].content[6].text = $sims' > payload.final.json curl -s https://api.anthropic.com/v1/messages \ -H "x-api-key: $ANTHROPIC_API_KEY" \ -H "anthropic-version: 2023-06-01" \ -H "content-type: application/json" \ -d @payload.final.json > out.json jq -r '.content[0].text' out.json > triage.json || echo '{}' > triage.json # Validate JSON to avoid posting garbage jq -e . triage.json >/dev/null 2>&1 || echo '{"labels":[],"severity":"low","duplicate_url":"","comment_markdown":"(triage failed to parse)"}' > triage.json - name: Apply labels (optional) if: ${{ false }} # flip to `true` to auto-apply labels uses: actions/github-script@v7 with: script: | const triage = JSON.parse(require('fs').readFileSync('triage.json','utf8')) if (triage.labels?.length) { await github.rest.issues.addLabels({ owner: context.repo.owner, repo: context.repo.repo, issue_number: context.issue.number, labels: triage.labels }) } - name: Post triage comment uses: actions/github-script@v7 with: script: | const fs = require('fs') const triage = JSON.parse(fs.readFileSync('triage.json','utf8')) const md = `### 🤖 Triage - **Suggested labels:** ${triage.labels?.join(', ') || '—'} - **Severity:** ${triage.severity || '—'} ${triage.duplicate_url ? `- **Possible duplicate:** ${triage.duplicate_url}\n` : ''} --- ${triage.comment_markdown || ''}` await github.rest.issues.createComment({ owner: context.repo.owner, repo: context.repo.repo, issue_number: context.issue.number, body: md }) ``` > [!NOTE] > The triage workflow posts a **suggestion comment** by default. Flip the `Apply labels` step to `true` if you want labels applied automatically. > > ### Configuration & Customization > > - **Model selection**: set `CLAUDE_MODEL` (e.g., `claude-3-5-sonnet-20240620`) where shown. > - **Secrets**: `ANTHROPIC_API_KEY` is required. The built‑in `GITHUB_TOKEN` is sufficient for posting comments and applying labels. > - **Permissions**: each workflow declares the least privileges it needs (`pull-requests: write` and/or `issues: write`). Adjust only if your org requires stricter policies. > - **Scope**: use `paths:` filters on triggers to limit when workflows run (e.g., only for `/src` or exclude `/docs`). > > ### Troubleshooting > > Check the **Actions logs** first—most issues are missing secrets/permissions or a mis‑indented YAML block. > > - **No comments appear on PRs**: Verify the Claude GitHub App is installed and the workflow has `pull-requests: write` permission. > - **403 when applying labels**: Ensure the job or step has `issues: write`. The default `GITHUB_TOKEN` must have access to this repo. > - **Anthropic API errors**: Confirm `ANTHROPIC_API_KEY` is set at repository (or org) level and not expired. > - **“YAML not well‑formed”**: Validate spacing—two spaces per nesting level; no tabs. --- <h1 id="help--troubleshooting">Help & Troubleshooting</h1> > [!TIP] > **Q:`claude` not found, but `npx claude` works?** > > > **A: Your `PATH` is missing the npm global bin. See the `PATH` issue section for [`Windows`](#windowspath) or [`Linux`](#linuxpath)** > > **Q:** **Which Node.js version do I need?** > > > **A:** **Node.js **18+** (ideally **20+**). Check with `node --version`.** > > **Q: Where do I see logs** > > > **A: Run `claude doctor` and `claude --verbose` the diagnostic window will point to log locations.** > > **Q: Do I need to reboot after editing PATH?** > > > **A: No reboot required, but you <mark>must</mark> open a <mark>new</mark> terminal window.** <table><td> <h2 id="debug-quick-commands">Debug Quick Commands</h2> _Check the output of `claude doctor` for log locations and environment checks._ > [!Note] > > ```bash > claude # Open Claude UI (if on PATH) > claude --version # Show CLI version (e.g., 1.0.xx) > claude update # Update the CLI (if supported) > > claude doctor # Open diagnostic / debug window > npx claude /doctor # Opens diagnostic/debug window > > claude --debug # Launch claude with diagnostics > claude --verbose # Verbose logging > > where claude # Windows (cmd) > which claude # macOS/Linux (bash/zsh) > > npm bin -g # Linux Verify your global bin path > npm prefix -g # Windows Verify your global bin path > ```                                                                                                                                                                                                          </td></table> <table><td> <h2 id="linuxpath">Path Temp Fix</h2> **Your **PATH** likely doesn’t include the global npm bin directory.** > [!Note] > > #### Windows (CMD): > > ```bash > set PATH=%USERPROFILE%\AppData\Roaming\npm;C:\Program Files\nodejs;%PATH% > where claude > claude --debugg > ``` > > #### Windows (PowerShell): > > ```powershell > $env:Path = "$env:USERPROFILE\AppData\Roaming\npm;C:\Program Files\nodejs;$env:Path" > where claude > claude --debugg > ``` > > #### Linux/MacOS (bash/zsh) > > ```bash > export PATH="$(npm config get prefix)/bin:$HOME/.local/bin:$PATH" > which claude > claude doctor > ```                                                                                                                                                                                                          </td></table> <table><td> <h2 id="windowspath">Windows Path Perm Fix</h2> **Replace `<you>` with your own Windows username (without the angle brackets)** - **Start → type: <kbd>Environment Variables</kbd>** - **Open <kbd>Edit the system environment variables</kbd> → <kbd>Environment Variables</kbd>** - **Under <kbd>User variables for</kbd> <mark><you></mark> select `Path` → `Edit` → `New` add:** ```path C:\Users\<you>\AppData\Roaming\npm C:\Program Files\nodejs</kbd> ``` > **Optional locations to add:** ```path C:\Users\<you>\.claude\local\bin C:\Users\<you>\.local\bin ``` - **Remove duplicates, any entry containing `%PATH%`, and stray quotes (`"`). Click `OK`.** - **Open a `new` Command Prompt/PowerShell and verify:** ```C where claude claude doctor ``` > [!Tip] > > ### Optional Run directly (when PATH is broken) > > > **Windows (PowerShell/cmd)** > > ```powershell > "%USERPROFILE%\AppData\Roaming\npm\claude.cmd" --version > "%USERPROFILE%\AppData\Roaming\npm\claude.cmd" doctor > ``` > > > **Or via npx:** > > ``` > npx claude doctor > ```                                                                                                                                                                                                          </td></table> <table><td> <h3 id="installation--nodejs-issues">Installation / Node.js Issues</h3> **Must be Node 18+ (20+ recommended)** ```bash node --version ``` **Clean uninstall** ```bash npm uninstall -g @anthropic-ai/claude-code ``` **Fresh install** ```bash npm install -g @anthropic-ai/claude-code ``` </td></table> <table><td> <h3 id="authentication-issues">Authentication Issues</h3> > *Verify your Anthropic API key is available to the CLI.* **PowerShell (Windows):** ```powershell echo $env:ANTHROPIC_API_KEY claude -p "test" --verbose ``` **bash/zsh (macOS/Linux):** ```bash echo $ANTHROPIC_API_KEY claude -p "test" --verbose ``` _If the variable is empty set it for your shell/profile or use your OS keychain/secrets manager._ </td></table> <table><td> <h3 id="permission--allowed-tools-issues">Permission / Allowed Tools Issues</h3> **Inspect permissions** ```bash claude config get allowedTools ``` **Reset permissions** ```bash claude config set allowedTools "[]" ``` **Minimal safe set (example)** ```bash claude config set allowedTools '["Edit","View"]' ``` </td></table> <table><td> <h3 id="mcp-model-context-protocol-issues">MCP (Model Context Protocol) Issues</h3> > **Debug MCP servers** ```bash claude --mcp-debug ``` > **List & remove MCP servers** ```bash claude mcp list claude mcp remove <server-name> ``` </td></table> <table><td> <h2 id="full-clean-reinstall-windows--powershell">Full Clean Reinstall (Windows / PowerShell)</h2> > [!Caution] > **The following removes Claude Code binaries, caches, and config under your user profile** > 1. Uninstall the global npm package ```powershell npm uninstall -g @anthropic-ai/claude-code ``` > 2. Remove leftover shim files ```powershell Remove-Item -LiteralPath "$env:USERPROFILE\AppData\Roaming\npm\claude*" -Force -ErrorAction SilentlyContinue Remove-Item -LiteralPath "$env:USERPROFILE\AppData\Roaming\npm\node_modules\@anthropic-ai\claude-code" -Recurse -Force -ErrorAction SilentlyContinue ``` > 3. Delete cached installer & native files ```powershell Remove-Item -LiteralPath "$env:USERPROFILE\.claude\downloads\*" -Recurse -Force -ErrorAction SilentlyContinue Remove-Item -LiteralPath "$env:USERPROFILE\.claude\local\bin\claude.exe" -Force -ErrorAction SilentlyContinue Remove-Item -LiteralPath "$env:USERPROFILE\.claude\local" -Recurse -Force -ErrorAction SilentlyContinue ``` > 4. Remove config and project-local files ```powershell Remove-Item -LiteralPath "$env:USERPROFILE\.claude.json" -Force -ErrorAction SilentlyContinue Remove-Item -LiteralPath "$env:USERPROFILE\.claude" -Recurse -Force -ErrorAction SilentlyContinue ``` > 5. Reinstall ```powershell npm install -g @anthropic-ai/claude-code ``` </td></table> <table><td> <h2 id="one-shot-health-check-copypaste">One‑Shot Health Check (copy/paste)</h2> **Windows (PowerShell):** ```powershell Write-Host "`n=== Node & npm ==="; node --version; npm --version Write-Host "`n=== Where is claude? ==="; where claude Write-Host "`n=== Try doctor ==="; try { claude doctor } catch { Write-Host "claude not on PATH" } Write-Host "`n=== API key set? ==="; if ($env:ANTHROPIC_API_KEY) { "Yes" } else { "No" } ``` **macOS/Linux (bash/zsh):** ```bash echo "=== Node & npm ==="; node --version; npm --version echo "=== Where is claude? ==="; which claude || echo "claude not on PATH" echo "=== Try doctor ==="; claude doctor || true echo "=== API key set? ==="; [ -n "$ANTHROPIC_API_KEY" ] && echo Yes || echo No ```                                                                                      </td></table> --- <table><td> <h2 id="appendix-useful-paths">Appendix: Useful Paths</h2> - **Windows npm global bin:** `C:\Users\<you>\AppData\Roaming\npm` - **Windows Node.js:** `C:\Program Files\nodejs` - **Claude local data (Win):** `C:\Users\<you>\.claude\` - **Claude config (Win):** `C:\Users\<you>\.claude.json` - **macOS/Linux npm global bin:** `$(npm config get prefix)/bin` (often `/usr/local/bin` or `$HOME/.npm-global/bin`)                                                                                      </td></table> ## Best Practices > Curated guidance for safe, fast, and correct use of the Claude Code CLI and interactive REPL. All commands and flags here match the current Anthropic docs as of **Aug 23, 2025**. <h2 id="effective-prompting">Effective Prompting</h2> ```bash # Good: Specific and detailed claude "Review UserAuth.js for security vulnerabilities, focusing on JWT handling" # Bad: Vague claude "check my code" ``` Tip: `claude "query"` starts the interactive REPL pre-seeded with your prompt; `claude -p "query"` runs **print mode** (non‑interactive) and exits. --- <h2 id="security-best-practices-main">Security Best Practices</h2> 1. **Start with minimal permissions** - Prefer explicit allows and denies, either on the CLI or in settings files. ```bash # Allow only what you need for this run claude --allowedTools "Read" "Grep" "LS" "Bash(npm run test:*)" ``` Or commit a project policy at `.claude/settings.json`: ```json { "permissions": { "allow": ["Read", "Grep", "LS", "Bash(npm run test:*)"], "deny": [ "WebFetch", "Bash(curl:*)", "Read(./.env)", "Read(./secrets/**)" ] } } ``` 2. **Handle secrets correctly** - Use environment variables for SDK/automation flows: ```bash export ANTHROPIC_API_KEY="your_key" # for SDK/print mode ``` - In the interactive REPL, prefer `/login` instead of hard‑coding tokens. - Deny access to sensitive files in settings (replaces older `ignorePatterns`): ```json { "permissions": { "deny": ["Read(./.env)", "Read(./.env.*)", "Read(./secrets/**)"] } } ``` 3. **Audit permissions regularly** ```bash # Project settings claude config list claude config get permissions.allow claude config get permissions.deny # Global settings claude config list -g ``` 4. **Avoid bypass modes in production** - Do **not** use `--dangerously-skip-permissions` outside isolated/dev sandboxes. - For unattended runs, combine narrow `--allowedTools` with `--disallowedTools` and project settings. --- <h2 id="performance-tips">Performance Tips</h2> 1. **Use machine‑readable output in automations** ```bash claude -p "summarize this error log" --output-format json # valid: text | json | stream-json ``` 2. **Bound non‑interactive work** ```bash claude -p "run type checks and summarize failures" --max-turns 3 # optionally also bound thinking: export MAX_THINKING_TOKENS=20000 ``` 3. **Keep sessions tidy** ```bash # Retain recent sessions only (default is 30 days) claude config set -g cleanupPeriodDays 20 ``` 4. **Limit context scope** ```bash # Grant access only to relevant paths to reduce scanning/noise claude --add-dir ./services/api ./packages/ui ``` 5. **Pick the right model** - CLI aliases: `--model sonnet` or `--model opus` (latest of that family). - For reproducibility in settings, pin a full model ID (e.g., `"claude-3-5-sonnet-20241022"`). --- <h2 id="monitoring--alerting">Monitoring & Alerting</h2> **1) Health checks** Use the built‑in **doctor** command to verify installation and environment. ```bash # Every 15 minutes */15 * * * * /usr/local/bin/claude doctor >/dev/null 2>&1 || \ mail -s "Claude Code doctor failed" admin@company.com </dev/null ``` **2) Log analysis batch job** ```bash # Daily analysis with non-interactive JSON output (print mode) 0 6 * * * tail -1000 /var/log/app.log | \ claude -p "Analyze errors, regressions, and suspect patterns; output JSON." \ --output-format json > /tmp/daily-analysis.json ``` **3) Telemetry (optional)** Claude Code emits OpenTelemetry metrics/events. Set exporters in settings/env (e.g., OTLP) and ship to your observability stack (Datadog, Honeycomb, Prometheus/Grafana, etc.). --- <h2 id="collaboration-best-practices">Collaboration Best Practices</h2> <h3 id="team-workflows">Team Workflows</h3> **1) Share versioned configuration** ```jsonc // .claude/settings.json (checked into the repo) { "permissions": { "allow": [ "Read", "Grep", "LS", "Bash(npm run lint)", "Bash(npm run test:*)", ], "deny": [ "WebFetch", "Read(./.env)", "Read(./.env.*)", "Read(./secrets/**)", ], }, // Pin a model here for reproducibility if desired, using a full model ID: "model": "claude-3-5-sonnet-20241022", } ``` **2) Documentation automation** ```bash # Update docs with explicit tasks claude "Update README.md to reflect the latest API endpoints and examples." claude "Generate TypeScript types from schema.prisma and write to /types." ``` **3) Code review standards** ```bash # Review a local diff with constrained tools git fetch origin main git diff origin/main...HEAD > /tmp/diff.patch claude --allowedTools "Read" "Grep" "Bash(git:*)" \ "Review /tmp/diff.patch using team standards: - Security best practices - Performance considerations - Code style compliance - Test coverage adequacy" ``` <h3 id="knowledge-sharing">Knowledge Sharing</h3> **1) Project runbooks** ```bash claude "Create a deployment runbook for this app: steps, checks, rollback." claude "Document onboarding for new developers: setup, commands, conventions." ``` **2) Architecture docs** ```bash claude "Update architecture docs to reflect new microservices." claude "Create sequence diagrams for the authentication flow." ``` > Tip: Keep durable context in **CLAUDE.md** at the project root. In the REPL, use `/memory` to manage it and `@path` to import file content into prompts. --- <h2 id="common-pitfalls-to-avoid">Common Pitfalls to Avoid</h2> <h3 id="security-pitfalls">Security</h3> **❌ Don’t** - Use `--dangerously-skip-permissions` on production systems - Hard‑code secrets in commands/config - Grant overly broad permissions (e.g., `Bash(*)`) - Run with elevated privileges unnecessarily **✅ Do** - Store secrets in env vars and credential helpers - Start from minimal `permissions.allow` and expand gradually - Audit with `claude config list` / `claude config get` - Isolate risky operations in containers/VMs <h3 id="performance-pitfalls">Performance</h3> **❌ Don’t** - Load an entire monorepo when you only need a package - Max out thinking/turn budgets for simple tasks - Ignore session cleanup **✅ Do** - Use `--add-dir` for focused context - Right‑size with `--max-turns` and `MAX_THINKING_TOKENS` - Set `cleanupPeriodDays` to prune old sessions <h3 id="workflow-pitfalls">Workflow</h3> **❌ Don’t** - Skip project context (`CLAUDE.md`) - Use vague prompts - Ignore errors/logs - Automate without testing **✅ Do** - Maintain and update `CLAUDE.md` - Be specific and goal‑oriented in prompts - Monitor via logs/OTel as appropriate - Test automation in safe environments first --- <h1 id="third-party-integrations">Third-Party Integrations</h1> <h2 id="deepseek-integration">DeepSeek Integration</h2> 1. ###### Have claude Code installed ``` npm install -g @anthropic-ai/claude-code ``` 2. ###### Config Environment Variables ```bash export ANTHROPIC_BASE_URL=https://api.deepseek.com/anthropic export ANTHROPIC_AUTH_TOKEN=${YOUR_API_KEY} export ANTHROPIC_MODEL=deepseek-chat export ANTHROPIC_SMALL_FAST_MODEL=deepseek-chat ``` 3. ###### Now all you need to do is launch `claude` Find more information from the [Official Deepseek Docs](https://api-docs.deepseek.com/guides/anthropic_api)

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