codewiki-mcp 1.0.0

MCP server providing AI-powered access to Google CodeWiki for open-source repositories

CodeWiki MCP Server

A Model Context Protocol (MCP) server that provides AI-powered access to Google CodeWiki for open-source repositories. Query any GitHub, GitLab, or Bitbucket repository and get instant, AI-generated answers about the codebase — all from your editor.

Features

• Playwright-powered rendering — CodeWiki is an Angular SPA; all page content is rendered via headless Chromium
• 4 MCP tools — topics overview, structure (JSON TOC), full/section content, interactive Gemini chat Q&A
• Structured diagram extraction — detects CodeWiki SPA diagrams, Mermaid blocks, and inline SVGs; parses Graphviz SVGs into entities and relationships
• Shared browser singleton — persistent background event loop with lazy Chromium launch, shared across all tools
• In-memory caching — TTLCache avoids redundant page renders (wiki pages cached for 5 min)
• Dual-strategy parser — handles CodeWiki's custom Angular elements (<body-content-section>, <documentation-markdown>) with fallback to standard HTML
• Pydantic input validation — schema-based validation with clear error messages
• Structured JSON responses — {status, code, message, data, meta} envelope
• URL normalization — accepts owner/repo shorthand or full URLs
• Environment variable configuration — override timeouts, retries, cache TTL, and limits
• Multi-transport — stdio (default) or SSE
• Graceful shutdown — SIGINT/SIGTERM handlers for clean Ctrl+C
• Modular architecture — tools in separate modules, easy to extend
• Response metadata — timing, char count, attempt info in every response
• Docker support — Dockerfile with Playwright included

Prerequisites

• Python 3.10+
• Playwright Chromium (playwright install chromium)

Installation

Option A — Install from PyPI (recommended)

pip install codewiki-mcp
playwright install chromium

That's it. You now have the codewiki-mcp command available globally:

codewiki-mcp                    # stdio (default)
codewiki-mcp --sse --port 8080  # SSE transport
codewiki-mcp --verbose           # debug logging

Option B — Install from source

git clone https://github.com/Cloudmeru/CodeWiki-MCP.git
cd CodeWiki-MCP
pip install .
playwright install chromium

For development (with test dependencies):

pip install -e ".[test]"

Option C — Docker

docker build -t codewiki-mcp .

# stdio (for MCP clients)
docker run -it --rm codewiki-mcp

# SSE (for HTTP access)
docker run -p 3000:3000 codewiki-mcp --sse --port 3000

# With custom config
docker run -e CODEWIKI_MAX_RETRIES=5 -e CODEWIKI_VERBOSE=true codewiki-mcp

Configuration

Environment Variables

Variable	Default	Description
CODEWIKI_HARD_TIMEOUT	60	Hard timeout per request (seconds)
CODEWIKI_HTTPX_TIMEOUT	30	HTTP timeout fallback (seconds)
CODEWIKI_PAGE_LOAD_TIMEOUT	30	Playwright page load timeout (seconds)
CODEWIKI_ELEMENT_WAIT_TIMEOUT	20	Element wait timeout (seconds)
CODEWIKI_RESPONSE_WAIT_TIMEOUT	45	Chat response wait timeout (seconds)
CODEWIKI_MAX_RETRIES	2	Max retry attempts
CODEWIKI_RETRY_DELAY	3	Delay between retries (seconds)
CODEWIKI_RESPONSE_MAX_CHARS	30000	Max response character count
CODEWIKI_CACHE_TTL	300	Page cache TTL (seconds)
CODEWIKI_CACHE_MAX_SIZE	50	Max pages in cache
CODEWIKI_RESPONSE_INITIAL_DELAY	5	Initial delay before polling chat response (seconds)
CODEWIKI_RESPONSE_POLL_INTERVAL	2	Interval between chat response polls (seconds)
CODEWIKI_RESPONSE_STABLE_INTERVAL	2	Stable response detection interval (seconds)
CODEWIKI_JS_LOAD_DELAY	3	Delay for JS/SPA loading (seconds)
CODEWIKI_VERBOSE	false	Enable debug logging
CODEWIKI_BASE_URL	https://codewiki.google	CodeWiki base URL

MCP Client Setup

VS Code (.vscode/mcp.json):

{
  "mcpServers": {
    "codewiki": {
      "command": "codewiki-mcp"
    }
  }
}

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "codewiki": {
      "command": "codewiki-mcp"
    }
  }
}

CLI Options

codewiki-mcp [--stdio | --sse] [--port PORT] [--verbose | -v]

Flag	Description
--stdio	Run with stdio transport (default)
--sse	Run with SSE transport
--port PORT	Port for SSE transport (default: 3000)
--verbose, -v	Enable debug logging

Tools

list_code_wiki_topics

Retrieve the overview and available topics for a repository. Returns the full wiki content as markdown.

Parameter	Type	Required	Description
repo_url	string	Yes	Full URL or owner/repo shorthand

Renders the page via Playwright, caches result for 5 minutes.

read_wiki_structure

Get a JSON list of documentation sections/topics for a repository. Use this to see what's available before reading specific sections.

Parameter	Type	Required	Description
repo_url	string	Yes	Full URL or owner/repo shorthand

Renders the page via Playwright, caches result for 5 minutes.

read_wiki_contents

View full or section-specific documentation. Without section_title, returns the full wiki (may be truncated). With section_title, returns just that section.

Parameter	Type	Required	Description
repo_url	string	Yes	Full URL or owner/repo shorthand
section_title	string	No	Title (or partial) of a section to retrieve

Renders the page via Playwright, caches result for 5 minutes.

search_code_wiki

Ask Google CodeWiki a question about an open-source repository. Uses the interactive Gemini-powered chat.

Parameter	Type	Required	Description
repo_url	string	Yes	Full URL or owner/repo shorthand
query	string	Yes	The question to ask

Opens a new browser context, interacts with the chat panel, waits for the streamed Gemini response.

Examples:

repo_url: https://github.com/microsoft/vscode-copilot-chat
query: Where are the Allow/Skip buttons implemented?

repo_url: microsoft/vscode
query: How does the extension activation work?

Response Format

All tools return structured JSON:

{
  "status": "ok",
  "data": "The response content...",
  "repo_url": "https://github.com/owner/repo",
  "query": "How does X work?",
  "meta": {
    "elapsed_ms": 450,
    "char_count": 3200,
    "attempt": 1,
    "max_attempts": 2,
    "truncated": false
  }
}

Error responses:

{
  "status": "error",
  "code": "TIMEOUT",
  "message": "Page took too long to load.",
  "repo_url": "https://github.com/owner/repo",
  "meta": { "elapsed_ms": 60000, "attempt": 2, "max_attempts": 2 }
}

Error codes: VALIDATION, TIMEOUT, DRIVER_ERROR, NO_CONTENT, INPUT_NOT_FOUND, INTERNAL, RETRY_EXHAUSTED

Project Structure

codewiki_mcp/
├── __init__.py        # Package init + version
├── __main__.py        # python -m entry point
├── browser.py         # Shared Playwright browser singleton + persistent event loop
├── cache.py           # TTLCache for rendered pages
├── config.py          # Env-var-driven configuration + SPA selectors
├── parser.py          # Playwright renderer + BeautifulSoup section parser
├── server.py          # MCP server setup + CLI
├── types.py           # Pydantic schemas + response models
└── tools/
    ├── __init__.py    # Tool registration
    ├── contents.py    # read_wiki_contents
    ├── search.py      # search_code_wiki (Playwright chat interaction)
    ├── structure.py   # read_wiki_structure
    └── topics.py      # list_code_wiki_topics
tests/
├── __init__.py        # Package marker
├── conftest.py        # Shared fixtures + sample data
├── test_cache.py      # Cache layer tests
├── test_config.py     # Configuration tests
├── test_parser.py     # Parser + HTML extraction tests
├── test_tools.py      # Server, tools & integration tests
└── test_types.py      # Schema & response tests
Dockerfile             # Docker deployment

Running Tests

pip install -e ".[test]"
pytest tests/ -v

Architecture

v1.0.0 — Playwright-everywhere

CodeWiki is an Angular SPA (<sdlc-agents-root>) — a plain HTTP GET returns an empty body. All page content is rendered client-side, so every tool uses Playwright headless Chromium.

Browser singleton

A persistent background event loop runs in a daemon thread. browser.py provides:

• _get_browser() — lazily launches a shared Chromium instance
• run_in_browser_loop(coro) — submits async work to the persistent loop from any sync context
• fetch_rendered_html(url) — navigates, waits for SPA content markers, returns the rendered HTML

All 4 tools share the same browser instance. Pages are cached in a TTLCache (5 min) so repeated requests skip the render.

SPA-aware parser

CodeWiki uses custom Angular elements instead of standard HTML:

• <body-content-section> — one per wiki section
• <documentation-markdown> — rendered markdown inside each section
• <chat> → <new-message-form> → <textarea data-test-id="chat-input"> — the Gemini chat

parser.py implements a dual-strategy section extractor:

1. CodeWiki SPA — looks for <body-content-section> + <documentation-markdown> elements
2. Standard HTML fallback — scans h1-h6 headings for non-CodeWiki pages

Structured diagram extraction

CodeWiki renders diagrams as <code-documentation-diagram-inline> elements containing base64-encoded SVGs. The parser detects three types of diagrams:

1. CodeWiki SPA diagrams — decodes data:image/svg+xml;base64,... from <image class="image-diagram"> elements, then parses Graphviz SVG structure
2. Mermaid blocks — captures raw source from <code class="mermaid"> and <div class="mermaid">
3. Fallback SVGs/images — bare <svg> with <title> or <img> matching diagram patterns

For Graphviz SVGs, it extracts structured graph data:

• Nodes — <g class="node"> groups → {id, label}
• Edges — <g class="edge"> groups → {from, to, label}

Diagram summaries (entities + relationships) are placed at the top of tool output so they remain visible even when responses are truncated.

Key components

• Playwright + shared browser — all page rendering via headless Chromium
• TTLCache — rendered pages cached for 5 minutes (configurable)
• BeautifulSoup + lxml — fast HTML parsing with section extraction, TOC, and diagram detection
• Pydantic schemas validate all inputs before processing
• Structured responses with JSON envelope and metadata
• Modular tools — each tool in its own module, registered via register_all_tools()
• Signal handlers — SIGINT/SIGTERM for clean shutdown with browser cleanup
• Environment variable configuration — all tunables configurable without code changes