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# ByteAsk Embedded MCP
**Page-cited answers from embedded & firmware reference docs — for coding agents that can't afford to guess a register value.**
[](https://smithery.ai/servers/kulkarnianirudha8/byteaskai)
[](LICENSE)
[](pyproject.toml)
[](https://modelcontextprotocol.io)
[](#)
[](#contributing)
[](https://docs.byteask.ai/embedded)
Official MCP Registry Namespace: `ai.byteask/embedded-docs` · Remote MCP Endpoint: `https://mcp.byteask.ai/mcp`
[Quickstart](#quickstart) · [Tools](#tools) · [Connect a client](#connect-a-client) · [Configuration](#configuration) · [Hosted server](#hosted-server) · [Contributing](#contributing)
<img src="assets/demo.gif" alt="A coding agent reaches for ETH_DMATDLAR from memory; byteask reads the corpus and the line snaps to the cited ETH_DMACTXDLAR with a page citation." width="820">
</div>
---
ByteAsk Embedded MCP is the open-source server behind [ByteAsk Embedded Docs](https://docs.byteask.ai/embedded):
a **source-grounded, page-cited evidence-retrieval** MCP server for coding agents
(Claude Code, Codex, Cursor) that write firmware / driver / protocol code and need
*exact* facts — SunSpec points, register offsets, Modbus function codes, trip
thresholds, SCPI commands, API symbols.
It returns **verbatim snippets with page citations** — never an authored answer — and
when nothing is relevant enough it says **no match** rather than fabricate. Every
document is treated equally: no authority layer, no filters.
> [!NOTE]
> **What's in this repo:** the MCP *server* — tools, transports (stdio + Streamable
> HTTP), bearer auth, DNS-rebinding protection, result rendering — plus a small,
> pluggable retrieval interface.
>
> **What's _not_ in this repo:** the retrieval engine and the document corpus. How
> documents are parsed, chunked, embedded, and ranked, and the licensed source
> material itself, sit behind the [`SearchBackend`](src/byteask_embedded_mcp/backend.py)
> seam and power the hosted endpoint at `https://mcp.byteask.ai/mcp`. This repo ships
> an in-memory [`SampleBackend`](src/byteask_embedded_mcp/backend.py) (a few
> illustrative, public-knowledge records) so the server runs out of the box.
## Why
- **Cited, or nothing.** Every hit is verbatim source text with a section + page
citation. On a miss it returns an honest "no confident match" — it never invents a
register value.
- **Built for coding agents.** The tool descriptions and triggers are tuned so agents
call `search_docs` reflexively the moment they see a hex literal, a Modbus code, an
IEEE clause, a SCPI verb, or an MCU part number — before answering from memory.
- **Two transports, one server.** `stdio` for local agents, Streamable HTTP for hosted.
- **Bring your own retrieval.** The search engine is a two-method interface — swap in
anything behind `BYTEASK_BACKEND` without touching the server.
- **Zero-setup demo.** The bundled `SampleBackend` runs immediately. No API keys.
## Quickstart
Requires Python ≥ 3.10 and [`uv`](https://docs.astral.sh/uv/).
```bash
uv sync
uv run byteask-embedded-mcp # run as an MCP server (stdio)
```
That's it — the bundled `SampleBackend` serves a couple of illustrative records, so
`search_docs` works immediately. Run the offline tests with `uv run pytest`.
## Connect a client
### Hosted (no install)
The hosted server speaks **Streamable HTTP** at `https://mcp.byteask.ai/mcp` and is
backed by the full licensed corpus.
[](https://cursor.com/install-mcp?name=byteask-embedded-docs&config=eyJ1cmwiOiJodHRwczovL21jcC5ieXRlYXNrLmFpL21jcCJ9)
**Claude Code:**
```bash
claude mcp add --transport http byteask-embedded-docs https://mcp.byteask.ai/mcp
```
<details>
<summary><strong>Codex, Cursor, and other clients (mcp-remote)</strong></summary>
```json
{
"mcpServers": {
"byteask-embedded-docs": {
"command": "npx",
"args": ["-y", "mcp-remote", "https://mcp.byteask.ai/mcp"]
}
}
}
```
</details>
### Local (this repo)
The project-scoped [`.mcp.json`](.mcp.json) registers the stdio server for clients
that read it. Manually, for Claude Code:
```bash
claude mcp add byteask-embedded-docs -- uv run byteask-embedded-mcp
```
## Tools
Input is natural language (or an exact identifier). Output is compact markdown.
| Tool | What it does |
|------|--------------|
| **`search_docs(query, limit=8)`** | Search the corpus; return ranked, page-cited evidence. Each hit has a document title, a section + page citation, the verbatim snippet, and a `result_id`. A "no confident match" response means *not found — do not fabricate*. |
| **`get_context(result_id)`** | Expand a hit to its full source section. |
| **`request_document(request)`** | Ask for a missing document to be added (logged server-side). |
Example output:
```markdown
## Results for "what Modbus function code writes multiple registers"
### Sample — Modbus Application Protocol (illustrative) — §6.12, p.30
> Function code 16 (0x10), Write Multiple Registers, writes a block of contiguous
> holding registers (1 to 123 registers) in a remote device. ...
_ref: sample:modbus-fc16_
```
## Plug in your own retrieval
The server depends only on a two-method interface
([`backend.py`](src/byteask_embedded_mcp/backend.py)):
```python
class SearchBackend(Protocol):
def search(self, query, limit=8, effort=None) -> dict: ...
def get_context(self, result_id, effort=None) -> dict: ...
```
Implement it, expose a factory `make_backend(config) -> SearchBackend`, and point the
server at it:
```bash
BYTEASK_BACKEND="my_pkg.my_module:make_backend"
```
The exact return-value contracts are documented at the top of `backend.py`.
## Configuration
All settings are environment variables (loaded from `.env`; see [`.env.example`](.env.example)).
| Variable | Default | Notes |
|----------|---------|-------|
| `BYTEASK_BACKEND` | — | `module:callable` returning a `SearchBackend`; empty → `SampleBackend` |
| `BYTEASK_LOGS` | `logs` | where query / request JSONL logs are written |
| `MCP_TRANSPORT` | `stdio` | `stdio` (local agents) or `http` |
| `MCP_HTTP_HOST` / `MCP_HTTP_PORT` | `127.0.0.1` / `8000` | HTTP bind address |
| `MCP_HTTP_AUTH_TOKEN` | — | bearer token for HTTP (empty = unauthenticated, dev only) |
| `MCP_ALLOWED_HOSTS` | — | comma-separated hosts allowed in the `Host` header (`*` disables) |
| `LOG_LEVEL` | `INFO` | stderr log verbosity |
<details>
<summary><strong>Running over HTTP</strong></summary>
```bash
MCP_TRANSPORT=http MCP_HTTP_AUTH_TOKEN=$(openssl rand -hex 32) \
uv run byteask-embedded-mcp --host 0.0.0.0 --port 8000
```
Clients then send `Authorization: Bearer <token>`. The bundled bearer check is a
shared-secret **stub** — replace it with real auth (OAuth 2.1 resource server, mTLS,
or a trusted reverse proxy) before exposing publicly. DNS-rebinding protection stays
on independently via `MCP_ALLOWED_HOSTS`.
</details>
## Hosted server
You don't need to run anything to use ByteAsk Embedded Docs. The hosted server gives
Claude Code, Codex, Cursor, and any MCP client exact, page-cited facts from embedded
and firmware reference docs — register maps, protocol function codes, SCPI commands,
standard thresholds, datasheet specs. The guarantee: *verbatim source, or "no match" —
never an invented value.*
| | |
|---|---|
| **Name** | `byteask-embedded-docs` |
| **Endpoint** | `https://mcp.byteask.ai/mcp` (Streamable HTTP) |
| **Docs & per-client setup** | <https://docs.byteask.ai/embedded> |
This repository is the open-source server that powers that endpoint.
## Project layout
```
src/byteask_embedded_mcp/
server.py # FastMCP app + 3 tools (search_docs, get_context, request_document)
backend.py # SearchBackend protocol + in-memory SampleBackend (swap for real retrieval)
render.py # structured result -> compact markdown
http_auth.py # Streamable HTTP entrypoint + stub bearer-token guard
config.py # server config (transport, logging, backend selection)
schemas.py # Hit / Section result types
obs.py # per-call JSONL logging
tests/ # offline unit tests (renderer, backend, server tools)
assets/ # README demo GIF + its deterministic generator
```
## Security
- **stdout stays clean** in stdio mode (it is the JSON-RPC channel); all logs go to
stderr / `logs/*.jsonl`.
- The HTTP **bearer check is a stub** — unauthenticated if no token is set, a shared
secret at best. Harden it before exposing widely.
- **DNS-rebinding protection** is on by default for the HTTP transport.
## Contributing
PRs and issues are welcome.
```bash
uv sync # install (incl. dev tools)
uv run pytest # run the offline test suite
```
A few conventions to keep the server clean:
- **The backend seam is the extension point.** Retrieval internals (parsing, chunking,
embeddings, ranking) are intentionally out of scope here — build them behind
`SearchBackend` in your own package, not in this repo.
- **Keep the dependency surface small** and the stdio path free of the HTTP stack.
- **Add a test** for new behavior; the suite is fully offline (no network, no keys).
## License
[MIT](LICENSE) © ByteAsk
