What is codebase-index?

A local search tool for understanding a codebase by meaning, symbols, and relationships between functions. It can also show call graphs, which map where functions are used and what they call.

Use it to discover symbols, search code by meaning, and inspect how functions connect across a project.

It helps find relevant code when exact text searches are not enough. This is useful in large projects where files and function relationships are difficult to trace manually.

codebase-index — MCP server by Helweg

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods

npx agentmods add mcp/helweg/open-codebase-index/codebase-index

Clone the repo

git clone --depth 1 https://github.com/Helweg/open-codebase-index

Made for: Claude Code, Codex, Cursor, Gemini CLI, OpenCode.

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

codebase-index scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.mcp.json · 13 lines

What it actually says

{
  "codebase-index": {
    "command": "npx",
    "args": [
      "-y",
      "--package",
      "opencode-codebase-index",
      "opencode-codebase-index-mcp",
      "--host",
      "codex"
    ]
  }
}

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

yesterday First seen · 13 lines scan A ee3e20e48380

Subscribe to this mod's changes

codebase-index is an MCP server published in the GitHub repository Helweg/open-codebase-index (183 stars, last pushed 2d ago), licensed MIT. Its token cost is not measured: an MCP server costs its tool schemas, not its config file. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Languages Research claude-code code-search codebase-indexing codex embeddings mcp

codebase-index

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

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