mcp-injector

# mcp-injector Claude Code reads raw files on demand, quickly exhausting your context window and budget. On a large codebase, this leads to slow responses and high API costs. mcp-injector fixes this. It runs as a background daemon, pre-indexes your entire repository into a local SQLite catalog, and serves a compressed snapshot of your whole codebase to Claude on every query at roughly 41-89% the normal token cost. I built this after my team's Claude API bill hit $400/month on a 500K line Spring Boot monorepo. After installing mcp-injector the same workflow costs ~$80/month. The difference is AST body folding (strips function bodies, keeps signatures) plus canonical determinism (byte-identical output every run so Anthropic's KV cache fires instead of miss). No cloud. No telemetry. Runs entirely on your machine.-- ## Real-World Codebase Context Benchmarks Estimate the impact of AST code compression on large open-source repositories (calculated at $3.00 / million input tokens for Claude 3.5 Sonnet): | Repository | Total Files | Raw Context Tokens | Compressed Context Tokens | Token Reduction | Cost Saved / Run | | :--- | :---: | :---: | :---: | :---: | :---: | | **Django** | 2,359 | 5,554,607 | 596,752 | **89.3%** | **$10.99** | | **Tokio** | 789 | 1,597,813 | 444,164 | **72.2%** | **$3.11** | | **Gin** | 99 | 197,300 | 47,718 | **75.8%** | **$0.39** | *Numbers are reproducible. Run the open-source benchmark tool on any public repository:* **[mcp-benchmark repository](https://github.com/foldwork-dev/mcp-benchmark)** --- ## What It Looks Like Run `mcp-benchmark` on your own project to see your exact savings before installing anything: ```text mcp-benchmark ./your-project ════════════════════════════════════════════════════════════════════════════════ mcp-benchmark - context Tier 3 compression | $3.00/1M tokens | 2026-07-06T12:00:00Z ════════════════════════════════════════════════════════════════════════════════ FILE RAW TOKENS COMPRESSED SAVED COST SAVED* ────────────────────────────────────────────────────────────────────────────────────────── cmd/license-gen/main.go 3,633 214 94.1% $0.0103 main.go 17,555 1,917 89.1% $0.0469 website/api/webhook.go 2,682 295 89.0% $0.0072 main_test.go 1,576 353 77.6% $0.0037 ────────────────────────────────────────────────────────────────────────────────────────── TOTAL (4 files) 25,446 2,779 89.1% $0.0680 * Based on $3.00 / 1M input tokens Running this codebase through Claude 10x/day costs $0.76/day raw. With mcp-injector: $0.08/day. You save $0.68/day ($20/month). ``` --- ## Tools ### `get_project_map` Returns a compressed structural overview of the workspace. Function bodies are folded and replaced with placeholders to reduce token usage. - `tier` (integer, optional): Compression tier to apply (default: 2). - `unfolded_files` (array of strings, optional): Workspace-relative paths or glob patterns for files to serve at full resolution (uncompressed). ### `injector_retrieve` Retrieves the full uncompressed source of a file from the local cache. - `path` (string, required): The workspace-relative path of the file to retrieve. - `retrievalKey` (string, optional): The SHA-256 retrieval key returned in a prior compressed payload. - `start_line` (integer, optional): 1-indexed start line for range retrieval. - `end_line` (integer, optional): 1-indexed end line for range retrieval. ### `injector_search` BM25-ranked full-text symbol search over the local SQLite catalog. - `query` (string, required): FTS5 query string (bare terms, "phrase", prefix*). - `limit` (integer, optional): Maximum results (default: 20). ### `injector_stats` Returns index status, current compression ratio, total files indexed, and cache hit rate. ### `injector_sync` Waits for all pending file index updates to complete. Call this after writing to a file and before calling `get_project_map`. --- ## Quick Install Install the daemon locally and configure your IDEs: ```bash curl -fsSL https://foldwork.dev/install | sh ``` *Automatically configures **Claude Desktop**, **Cursor IDE**, and **VS Code**.* --- ## Getting Started ### Step 1: Check if your project qualifies for the free tier Run the benchmark CLI on your project to see your token savings and line count: ```bash mcp-benchmark ./your-project ``` If your project is under 50,000 lines, mcp-injector is completely free. The benchmark output shows your exact line count. ### Step 2: Install the daemon ```bash curl -fsSL https://foldwork.dev/install | sh ``` The installer auto-detects Claude Desktop, Cursor, VS Code, and Devin Desktop and writes the MCP config automatically. You should see output like: ```text * mcp-injector v0.2.0 installed to /usr/local/bin/mcp-injector * Claude Desktop configured * Cursor configured Restart your IDE and mcp-injector will be active. ``` ### Step 3: Restart your IDE The MCP server starts automatically when your IDE launches. No separate daemon process to manage. ### Step 4: Verify it is working In Claude Code or Cursor, ask Claude: > "Use get_project_map to show me the structure of this project" Claude will call the mcp-injector tool and return a compressed map of your entire codebase. If you see module names, entry points, and dependency information - it is working. ### Step 5: Get the full source when needed When Claude needs to see the complete implementation of a compressed function, it automatically calls `injector_retrieve`. You can also trigger this explicitly: > "Show me the full implementation of UserService.java" Claude will fetch the uncompressed source from the local cache. ### Step 6: Check your savings ```bash injector_stats ``` Or ask Claude directly: "Call injector_stats and tell me my current token savings." --- ## Advanced Usage ### Inspecting specific files uncompressed Sometimes you need Claude to see the exact implementation of a file while keeping the rest compressed. Use the `unfolded_files` parameter: In your MCP call or by asking Claude: > "Get the project map but show me src/auth/handler.go at full resolution" This passes `"unfolded_files": ["src/auth/handler.go"]` to get_project_map. That file is served raw; everything else stays compressed. Glob patterns work too: - `"**/*_test.go"` - all test files uncompressed - `"src/auth/*.go"` - all files in a directory uncompressed ### Switching branches mcp-injector installs a `post-checkout` git hook when it first runs. Branch switching automatically triggers a full re-index. You will see this in the daemon logs: ```text [mcp-injector] Branch switched to feature/auth-refactor, re-indexing... [mcp-injector] Re-index complete in 4.2s (47,293 lines indexed) ``` ### Security First: Zero-Leak Guarantee Enterprise security teams often block AI coding tools because developers accidentally leak sensitive credentials in their context window. mcp-injector solves this locally. The daemon includes a built-in Shannon entropy filter that analyzes all AST strings and comments in real-time. If it detects high-entropy strings (like AWS Access Keys, SSH private keys, or database passwords), it dynamically redacts them as `[REDACTED: high entropy]` *before* they ever leave your machine. Your API credentials are never sent to Anthropic. If your codebase has a hardcoded API key or AWS credential, the `get_project_map` response will include: ```json "secrets_redacted": 2, "files_with_redactions": ["config/db.go", "scripts/deploy.sh"] ``` The actual values are replaced with `[REDACTED: high entropy]`. Variable names are preserved so Claude still understands the code structure. ### Manual MCP configuration If the auto-installer does not detect your IDE, add this to your MCP config manually: ```json { "mcpServers": { "mcp-injector": { "command": "/usr/local/bin/mcp-injector", "env": { "MCP_WORKSPACE": "${workspaceFolder}" } } } } ``` Config file locations: - Claude Desktop (Mac): `~/Library/Application Support/Claude/claude_desktop_config.json` - Claude Desktop (Windows): `%APPDATA%\Claude\claude_desktop_config.json` - Claude Desktop (Linux): `~/.config/Claude/claude_desktop_config.json` - Cursor: `~/.cursor/mcp.json` - VS Code: `.vscode/mcp.json` - Devin Desktop: `~/.devin/mcp.json` --- ## How It Works * **Persistent Local Daemon:** Indexes your repository structure into a high-performance WAL-mode SQLite database catalog. * **Smart File Watchers:** Monitors files incrementally via OS notification hooks (`inotify`/`FSEvents`) and local `git post-checkout` / `post-merge` triggers. * **Branch-Aware Re-indexing:** Installs a `post-checkout` git hook on startup. Switching branches triggers automatic workspace re-indexing. `get_project_map` always reflects your current branch including uncommitted changes. * **Canonical Output Determinism:** Guarantees byte-identical outputs across runs, maximizing Claude's **KV prompt caching** hits. * **Compress-Cache-Retrieve (CCR):** Employs lossless AST compression. The LLM gets the high-level outline and calls `injector_retrieve` to fetch raw file bodies on-demand. * **100% Local & Offline:** Running entirely on your local machine, keeping your intellectual property private and secure. **Supports:** Go, Python, TypeScript, JavaScript, Java, C++, Rust. --- ## Pricing Tiers * **Free Tier:** Workspaces under 50,000 total source lines (all tools and features fully active). * **Pro Tier ($12/month or $99/year):** Unlocks unlimited workspace sizes and high-speed incremental diff indexing. **[Activate Pro at foldwork.dev](https://foldwork.dev/#pricing)** --- ## Exposed MCP Tools * **`get_project_map`** - Generates a hierarchical outline of module exports, structures, and internal dependencies. * `unfolded_files` parameter: pass specific file paths or glob patterns to receive those files uncompressed while everything else stays folded. * `git_context`: always includes current branch, changed files, and recent commits in the response. * `secrets_redacted`: count of credentials automatically redacted before sending to Claude. Example call: ```json { "tool": "get_project_map", "arguments": { "tier": 3, "unfolded_files": ["src/auth/handler.go", "**/*_test.go"] } } ``` * **`injector_retrieve`** - Retrieves the raw source code of any compressed symbol from the local cache. Supports `start_line` and `end_line` parameters for surgical snippet extraction. * **`injector_search`** - BM25 full-text search over indexed symbols. Returns line ranges, symbol types, and context snippets so you can skip redundant file retrievals. * **`injector_stats`** - Visualizes index status, current token savings, and CCR cache hit rates. * **`injector_sync`** - Synchronously waits for the daemon to finish indexing pending filesystem edits. Returns a list of exactly which files were reindexed to confirm changes. ### Check your ROI (Savings Dashboard) You can run `mcp-injector status` in your terminal at any time. This CLI dashboard visually proves your exact token savings and estimated dollars saved by comparing your raw codebase tokens against the AST-compressed tokens in real-time. --- ## Security mcp-injector automatically redacts secrets and credentials before they reach Claude's context window: - AWS access keys, GitHub PATs, Stripe secret keys - JWT tokens and bearer tokens - High-entropy strings detected via Shannon entropy analysis - Private key headers (`-----BEGIN RSA PRIVATE KEY-----`) - **Air-Gapped Ready:** Pro license validation uses strictly offline Ed25519 cryptography. The daemon never makes an outbound network request, even to verify your subscription. Redacted content is replaced with `[REDACTED BY MCP-INJECTOR]`. A count of redactions is included in the `get_project_map` response so you always know what was protected. Your code never leaves your machine. Redaction happens locally before compression, and is always-on - it cannot be disabled. --- ## Uninstall To remove mcp-injector completely: ```bash # Remove binary sudo rm /usr/local/bin/mcp-injector # Remove index cache and logs rm -rf ~/.mcp-injector/ # Remove from IDE MCP config (edit manually): # Claude Desktop (Linux): ~/.config/Claude/claude_desktop_config.json # Claude Desktop (macOS): ~/Library/Application Support/Claude/claude_desktop_config.json # Cursor: ~/.cursor/mcp.json # VS Code: .vscode/mcp.json # Devin Desktop: ~/.devin/mcp.json # (Remove the "mcp-injector" entry from mcpServers) ``` --- ## What Gets Redacted mcp-injector automatically redacts the following before your code reaches Claude: | Pattern | Example Match | | :--- | :--- | | AWS access key IDs | `AKIAIOSFODNN7EXAMPLE` | | GitHub PATs (ghp_, ghs_) | `ghp_aBcDeFg...` | | Stripe secret keys | `sk_live_abc...` / `sk_test_abc...` | | JWT tokens | `eyJ...` | | PEM private key headers | `-----BEGIN RSA PRIVATE KEY-----` | | Generic high-entropy strings >20 chars | Detected via Shannon entropy | | Password / secret / token assignments | `password = "abc123"` | Redacted values are replaced with `[REDACTED BY MCP-INJECTOR]`. File paths and variable **names** are never redacted - only the values. --- ## License Commercial. Free tier available. Source code not public. Support Contact: [foldwork@proton.me](mailto:foldwork@proton.me)