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

Instructions

Implementation Reference

• src/RTFD/providers/dockerhub.py:375-405 (handler)

  The main MCP tool handler function `fetch_docker_image_docs` that orchestrates fetching the Docker image documentation by delegating to the private `_fetch_image_docs` helper and serializing the response.
  async def fetch_docker_image_docs(image: str, max_bytes: int = 20480) -> CallToolResult: """ Fetch actual Docker image documentation and README from DockerHub. USE THIS WHEN: You need usage instructions, environment variables, volume mounts, or examples. BEST FOR: Understanding how to use a Docker image and configure it properly. Better than using curl or WebFetch because it: - Extracts README content from DockerHub - Includes image description and key details - Formats content in readable Markdown - Prioritizes important sections (Usage, Environment Variables, Examples) Typical content includes: - How to run the container - Available environment variables - Volume mount points - Port configurations - Usage examples and docker-compose snippets Args: image: Docker image name (e.g., "nginx", "postgres", "redis") max_bytes: Maximum content size, default 20KB (increase for detailed docs) Returns: JSON with README content, size, and source info Example: fetch_docker_image_docs("nginx") → Returns README with usage instructions """ result = await self._fetch_image_docs(image, max_bytes) return serialize_response_with_meta(result)
• src/RTFD/providers/dockerhub.py:163-223 (helper)

  Core helper method `_fetch_image_docs` that fetches image metadata, extracts and formats README/description content, handles truncation, and returns structured documentation data.
  async def _fetch_image_docs(self, image: str, max_bytes: int = 20480) -> dict[str, Any]: """Fetch documentation for a Docker image. Args: image: Image name (e.g., 'nginx', 'postgres', 'myuser/myimage') max_bytes: Maximum content size in bytes Returns: Dict with documentation content """ try: metadata = await self._fetch_image_metadata(image) # Check if we got an error if "error" in metadata: return { "image": image, "content": "", "error": metadata["error"], "size_bytes": 0, "source": None, } # Extract readme if available readme = metadata.get("readme", "") description = metadata.get("description", "") # Combine description and readme content = "" if description: content = f"## Description\n\n{description}\n\n" if readme: content += f"## README\n\n{readme}" elif not description: content = "No documentation available for this image." # Truncate if necessary content_bytes = content.encode("utf-8") if len(content_bytes) > max_bytes: content = content[:max_bytes] truncated = True else: truncated = False return { "image": image, "content": content, "size_bytes": len(content.encode("utf-8")), "source": "dockerhub", "truncated": truncated, } except Exception as exc: return { "image": image, "content": "", "error": f"Failed to fetch docs: {exc!s}", "size_bytes": 0, "source": None, }
• src/RTFD/providers/dockerhub.py:436-444 (registration)

  Tool registration within the `get_tools` method where `fetch_docker_image_docs` is conditionally added to the tools dictionary if fetching is enabled.
  tools = { "search_docker_images": search_docker_images, "docker_image_metadata": docker_image_metadata, } if is_fetch_enabled(): tools["fetch_docker_image_docs"] = fetch_docker_image_docs tools["fetch_dockerfile"] = fetch_dockerfile return tools
• src/RTFD/providers/dockerhub.py:20-34 (registration)

  Tool name registration in the `get_metadata` method where "fetch_docker_image_docs" is conditionally appended to the list of exposed tool names.
  def get_metadata(self) -> ProviderMetadata: tool_names = ["search_docker_images", "docker_image_metadata"] if is_fetch_enabled(): tool_names.append("fetch_docker_image_docs") tool_names.append("fetch_dockerfile") return ProviderMetadata( name="dockerhub", description="DockerHub Docker image search and metadata", expose_as_tool=True, tool_names=tool_names, supports_library_search=False, # DockerHub search is image-centric, not lib-doc required_env_vars=[], optional_env_vars=[], )