codesurface

MCP server that indexes your codebase's public API at startup and serves it via compact tool responses — saving tokens vs reading source files.

Parses source files, extracts public classes/methods/properties/fields/events, and serves them through 5 MCP tools. Works with Claude Code, Cursor, Windsurf, or any MCP-compatible AI tool.

Supported languages: C# (.cs), Go (.go), Java (.java), Python (.py), TypeScript/TSX (.ts, .tsx)

Quick Start

Add to your .mcp.json:

{
  "mcpServers": {
    "codesurface": {
      "command": "uvx",
      "args": ["codesurface", "--project", "/path/to/your/src"]
    }
  }
}

Point --project at any directory containing supported source files — a Unity Assets/Scripts folder, a Spring Boot project, a .NET src/ tree, a Node.js/React project, a Python package, etc. Languages are auto-detected.

Restart your AI tool and ask: "What methods does MyService have?"

CLAUDE.md Snippet

Add this to your project's CLAUDE.md (or equivalent instructions file). This step is important. Without it, the AI has the tools but won't know when to reach for them.

## Codebase API Lookup (codesurface MCP)

Use codesurface MCP tools BEFORE Grep, Glob, Read, or Task (subagents) for any class/method/field lookup. This applies to you AND any subagents you spawn.

| Tool | Use when | Example |
|------|----------|---------|
| `search` | Find APIs by keyword | `search("MergeService")` |
| `get_signature` | Need exact signature | `get_signature("TryMerge")` |
| `get_class` | See all members on a class | `get_class("BlastBoardModel")` |
| `get_stats` | Codebase overview | `get_stats()` |

Every result includes file path + line numbers. Use them for targeted reads:
- `File: Service.cs:32` → `Read("Service.cs", offset=32, limit=15)`
- `File: Converter.java:504-506` → `Read("Converter.java", offset=504, limit=10)`

Never read a full file when you have a line number. Only fall back to Grep/Read for implementation details (method bodies, control flow).

Tools

Tested On

Line Numbers for Targeted Reads

Every record includes line_start and line_end (1-indexed). Multi-line declarations span the full signature:

[METHOD] com.google.common.base.Converter.from
  Signature: static Converter<A, B> from(Function<...> forward, Function<...> backward)
  File: Converter.java:504-506          ← multi-line signature

[METHOD] server.AlbumController.createAlbum
  Signature: createAlbum(@Auth() auth: AuthDto, @Body() dto: CreateAlbumDto)
  File: album.controller.ts:46          ← single-line

This lets AI agents do targeted reads instead of reading full files:

# Instead of reading the entire 600-line file:
Read("Converter.java")                     # 600 lines, ~12k tokens

# Read just the method + context:
Read("Converter.java", offset=504, limit=10)  # 10 lines, ~200 tokens

Benchmarks

Measured across 5 real-world projects in 5 languages, each using a 10-step cross-cutting research workflow.

Even with follow-up reads for implementation detail, the hybrid MCP + targeted Read approach uses 44% fewer tokens than a skilled Grep+Read agent and 87% fewer than a naive agent:

Per-question breakdown

See workflow-benchmark.md for the full step-by-step analysis across all languages.

Multiple Projects

Each --project flag indexes one directory. To index multiple codebases, run separate instances with different server names:

{
  "mcpServers": {
    "codesurface-backend": {
      "command": "uvx",
      "args": ["codesurface", "--project", "/path/to/backend/src"]
    },
    "codesurface-frontend": {
      "command": "uvx",
      "args": ["codesurface", "--project", "/path/to/frontend/src"]
    }
  }
}

Each instance gets its own in-memory index and tools. The AI agent sees both and can query across projects.

Setup Details

Using pip install:

pip install codesurface

{
  "mcpServers": {
    "codesurface": {
      "command": "codesurface",
      "args": ["--project", "/path/to/your/src"]
    }
  }
}

codesurface/
├── src/codesurface/
│   ├── server.py           # MCP server — 5 tools
│   ├── db.py               # SQLite + FTS5 database layer
│   └── parsers/
│       ├── base.py         # BaseParser ABC
│       ├── csharp.py       # C# parser
│       ├── go.py           # Go parser
│       ├── java.py         # Java parser
│       ├── python_parser.py # Python parser
│       └── typescript.py   # TypeScript/TSX parser
├── pyproject.toml
└── README.md

"No codebase indexed"

• Ensure --project points to a directory containing supported source files (.cs, .go, .java, .py, .ts, .tsx)
• The server indexes at startup — check stderr for the "Indexed N records" message

Server won't start

• Check Python version: python --version (needs 3.10+)
• Check mcp[cli] is installed: pip install mcp[cli]

Stale results after editing source files

• The index auto-refreshes on query misses — if you add a new class and query it, the server reindexes and retries automatically
• You can also call reindex() manually to force an incremental update

Contact

[email protected]

License

PolyForm Noncommercial 1.0.0

Free to use, fork, modify, and share for any personal or non-commercial purpose.
Commercial use requires permission.