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Ast Explorer MCP Server

Developer ToolsUse Caution4.8MCP RegistryLocal
Free

Server data from the Official MCP Registry

Python symbol exploration for codebase onboarding agents.

About

Python symbol exploration for codebase onboarding agents.

Security Report

4.8
Use Caution4.8High Risk

This is a well-structured MCP server for Python codebase symbol exploration using LibCST. The code is clean with proper error handling, no hardcoded credentials, and appropriate input validation. Permissions match the intended purpose of local filesystem analysis. Minor code quality observations exist but do not indicate security concerns. Supply chain analysis found 6 known vulnerabilities in dependencies (1 critical, 3 high severity). Package verification found 1 issue.

7 files analyzed · 11 issues found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

File System Read

Reads files on your machine. Normal for tools that analyze or process local data.

env_vars

Check that this permission is expected for this type of plugin.

How to Install

Add this to your MCP configuration file:

{
  "mcpServers": {
    "io-github-lovranran-mcp-ast-explorer": {
      "args": [
        "mcp-ast-explorer"
      ],
      "command": "uvx"
    }
  }
}

Documentation

View on GitHub

From the project's GitHub README.

mcp-ast-explorer

MCP server for deterministic Python codebase symbol exploration.

mcp-ast-explorer indexes Python source files with LibCST and exposes focused MCP tools for codebase onboarding: definition lookup, function signatures, local references, direct call chains, and simple class hierarchy queries.

Codebase Onboarding Stack

mcp-ast-explorer is the semantic symbol layer in a three-server MCP tool stack for Project 6 wayfinder, a codebase onboarding agent.

  • mcp-repo-mapper maps repository structure, languages, entry points, framework evidence, and Python dependency edges.
  • mcp-ast-explorer provides symbol-grounded Python definition, signature, reference, call-chain, and class-hierarchy lookups.
  • mcp-test-runner runs local pytest/Jest checks and coverage summaries so agent claims can be verified against execution.

In wayfinder, this server feeds entry-point and symbol explanation while refusing to invent missing symbols.

Status

This is a Python-only v1. TypeScript is registered as an unsupported backend placeholder so the server has an explicit extension point, but TypeScript analysis is not implemented yet.

The server does not use an LLM for symbol lookup. If a requested symbol or class is not present in the parsed index, tools return a structured not-found result instead of inventing an answer.

Tools

ToolPurpose
health()Returns ok for smoke checks.
find_definition(path, symbol, language="python")Finds a module, class, function, or method definition.
function_signature(path, symbol, language="python")Returns the signature for a function or method symbol.
find_references(path, symbol, language="python")Returns same-module CST name references for an existing symbol.
call_chain(path, from_symbol, depth=2, language="python")Returns direct callers detected from local references.
class_hierarchy(path, class_name, language="python")Returns direct subclasses detected from simple base-class names.

Supported Scope

  • Python files parsed by LibCST.
  • Symbol kinds: modules, classes, functions, and methods.
  • Same-module reference lookup for simple names.
  • Direct caller detection from function or method containers.
  • Direct subclass detection for simple class Child(Base): inheritance.
  • Structured error responses for unsupported languages and missing symbols.

Current Limitations

  • Cross-file imports and package-wide resolution are out of scope for v1.
  • Aliases, star imports, dynamic attribute access, and qualified references are not resolved.
  • call_chain currently returns direct callers only; recursive multi-hop expansion is not implemented.
  • class_hierarchy currently returns direct subclasses only and handles simple base names.
  • TypeScript is intentionally unsupported in v1.

Local Development

Install dependencies:

uv sync --extra dev

Run the MCP server:

uv run mcp-ast-explorer

Run verification:

uv run ruff check .
uv run mypy
uv run pytest

License

MIT

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