@vforvaick/pi-codebase-memory-mcp

Unofficial pi coding agent extension wrapping the codebase-memory-mcp binary.

Not affiliated with DeusData/codebase-memory-mcp. MIT.

What it does

• Registers 9 cbm_* tools the LLM can call: cbm_index, cbm_projects, cbm_search, cbm_trace, cbm_architecture, cbm_snippet, cbm_query (Cypher), cbm_changes (impact analysis), cbm_coverage.
• Freshness gate: auto-reindexes the graph (mode=moderate) before any read query when source has changed. The CBM binary's native watcher is inert in CLI / MCP-stdio mode (its daemon worker log stays 0 bytes, never fires), so without this gate the graph goes stale after every edit until a manual cbm_index.
• project is auto-inferred from the session cwd, so callers rarely pass it.

Prerequisites

1. pi coding agent installed.
2. codebase-memory-mcp binary on PATH. Install from upstream:

   curl -fsSL https://raw.githubusercontent.com/DeusData/codebase-memory-mcp/main/install.sh | bash
   

   Verify: codebase-memory-mcp --version.

Install

pi install npm:@vforvaick/pi-codebase-memory-mcp

After install, restart pi.

Usage

In any repo:

cbm_index               # one-time index (mode=moderate)
cbm_search .*Router.*   # find symbols
cbm_trace myFunction --direction both
cbm_architecture

Once indexed, the graph auto-refreshes after edits (see Freshness gate below). Tools auto-appear in the function list.

Freshness gate

The extension keeps a per-cwd dirty flag, bumped by pi lifecycle hooks:

• session_start -> mark cwd dirty (forces one reindex on first query, catches cross-session drift)
• tool_execution_end for edit / write / bash / ctx_execute / apply_patch (on success) -> mark dirty
• user_bash -> mark dirty conservatively

Before each read query (cbm_search, cbm_trace, etc.) the extension calls ensureFresh(cwd): if the cwd is dirty or git HEAD has drifted since the last index, it reindexes (mode=moderate) then serves the query. Race-safe via a per-cwd in-flight lock + dirty generation counter.

What the gate does NOT catch: mutations from external editors or other terminals (VSCode, sed in another shell) after the first query in a session. For those, run cbm_index manually.

Configuration

• CBM_BIN environment variable overrides the binary path. Default: codebase-memory-mcp (looked up on PATH).

Compatibility

• Tested against codebase-memory-mcp v0.9.0.
• Support policy: current + previous minor of codebase-memory-mcp.
• Known v0.9.0 quirk: check_index_coverage returns "unknown tool" via MCP. This extension routes it through cli mode, where it works. Tool list parity (advertised vs callable) is tracked upstream.

Security

• Runs the codebase-memory-mcp binary with the same filesystem access as your pi session.
• No telemetry. No network calls. Source is open - review before install.
• pi packages run with full system access; review the source at the repo before installing.

License

MIT. (C) vforvaick.

Contributing

PRs welcome at github.com/vforvaick/pi-codebase-memory-mcp.