RTFD (Read The F*****g Docs)

Instructions

Implementation Reference

• src/RTFD/providers/npm.py:199-223 (handler)

  The main handler function for the 'fetch_npm_docs' MCP tool. It invokes the internal helper and serializes the result into CallToolResult format.
  async def fetch_npm_docs(package: str, max_bytes: int = 20480) -> CallToolResult: """ Fetch actual npm package documentation from npm registry README. USE THIS WHEN: You need installation instructions, usage examples, API reference, or quickstart guides. BEST FOR: Getting complete, formatted documentation for JavaScript/Node.js packages. Better than using curl or WebFetch because it: - Automatically extracts relevant sections (Installation, Usage, Examples, API) - Prioritizes most useful content sections - Already in Markdown format (npm requires Markdown READMEs) NOT SUITABLE FOR: External documentation sites (use docs_url from npm_metadata + WebFetch) Args: package: npm package name (e.g., "express", "react", "axios") max_bytes: Maximum content size, default 20KB (increase for large packages) Returns: JSON with actual documentation content, size, truncation status, version Example: fetch_npm_docs("express") → Returns formatted README with installation and usage """ result = await self._fetch_npm_docs(package, max_bytes) return serialize_response_with_meta(result)
• src/RTFD/providers/npm.py:100-172 (helper)

  Internal helper method containing the core logic to fetch npm registry data, process README content, extract/prioritize sections, truncate if necessary, and handle errors.
  async def _fetch_npm_docs(self, package: str, max_bytes: int = 20480) -> dict[str, Any]: """ Fetch documentation content for npm package. Args: package: Package name max_bytes: Maximum content size in bytes Returns: Dict with content, size, source info """ try: url = f"https://registry.npmjs.org/{package}" async with await self._http_client() as client: resp = await client.get(url) resp.raise_for_status() data = resp.json() # npm registry includes README in "readme" field (already Markdown) content = data.get("readme", "") # If no README or very short, note it source = "npm" if not content or len(content.strip()) < 100: content = ( f"# {package}\n\n{data.get('description', 'No description available.')}\n\n" ) source = "npm_minimal" # Extract and prioritize sections sections = extract_sections(content) if sections: final_content = prioritize_sections(sections, max_bytes) # Fallback: simple truncation elif len(content.encode("utf-8")) > max_bytes: encoded = content.encode("utf-8")[:max_bytes] # Handle multi-byte characters while len(encoded) > 0: try: final_content = encoded.decode("utf-8") break except UnicodeDecodeError: encoded = encoded[:-1] else: final_content = content return { "package": package, "content": final_content, "size_bytes": len(final_content.encode("utf-8")), "source": source, "truncated": len(content.encode("utf-8")) > max_bytes, "version": data.get("version"), } except httpx.HTTPStatusError as exc: return { "package": package, "content": "", "error": f"npm registry returned {exc.response.status_code}", "size_bytes": 0, "source": None, } except Exception as exc: return { "package": package, "content": "", "error": f"Failed to fetch docs: {exc!s}", "size_bytes": 0, "source": None, }
• src/RTFD/providers/npm.py:19-32 (registration)

  Provider metadata declaration that conditionally includes 'fetch_npm_docs' in the list of available tools.
  def get_metadata(self) -> ProviderMetadata: tool_names = ["npm_metadata"] if is_fetch_enabled(): tool_names.append("fetch_npm_docs") return ProviderMetadata( name="npm", description="npm package registry metadata and documentation", expose_as_tool=True, tool_names=tool_names, supports_library_search=True, required_env_vars=[], optional_env_vars=[], )
• src/RTFD/providers/npm.py:225-229 (registration)

  Registration of the 'fetch_npm_docs' function in the tools dictionary returned by get_tools() method for MCP integration.
  tools = {"npm_metadata": npm_metadata} if is_fetch_enabled(): tools["fetch_npm_docs"] = fetch_npm_docs return tools