Codebase Memory MCP

Codebase Memory MCP

Purpose

Bring up codebase-memory-mcp for the owning Git checkout and prove the graph is usable before relying on it for code discovery. Keep linked worktrees on the owner's graph instead of creating one graph per branch.

When to use

• Initialize, re-index, refresh, or troubleshoot a repository graph.
• Use search_graph, trace_path, get_code_snippet, or query_graph.
• Verify that a repository is indexed before graph-backed exploration.
• Audit or prune duplicate linked-worktree indexes without deleting cache files directly.

Workflow

1. Verify the repository and binary.
   • git rev-parse --show-toplevel
   • git status -sb
   • command -v codebase-memory-mcp
   • codebase-memory-mcp --version
2. Resolve the canonical owning checkout.
   • scripts/codebase-memory-graph.sh canonical --repo "$(git rev-parse --show-toplevel)"
   • Linked worktrees resolve through their absolute Git common directory to the one checkout that owns it.
   • Separate clones remain separate projects.
   • Independent roots under ~/.codex/worktrees, ~/GIT/_Worktrees, any .worktrees component, /tmp, or /private/tmp are never indexed. Linked worktrees under those paths may only rewrite to one existing nonreserved owner.
   • Missing, invalid, bare, ambiguous, ownerless, reserved-owner, or NUL-containing repositories fail closed.
3. Prefer exposed MCP graph tools for discovery.
   • Installer or client configuration must separately disable the MCP index_repository tool because it cannot enforce the canonical indexing boundary. For Codex installs, render the private disabled_tools configuration accordingly.
   • When a graph is missing, run scripts/codebase-memory-graph.sh index --repo "$(git rev-parse --show-toplevel)" --mode full.
   • Use search_graph, trace_path, and get_code_snippet before broad text scans.
4. Use the helper for CLI indexing.
   • scripts/codebase-memory-graph.sh init --repo "$(git rev-parse --show-toplevel)" --mode full
   • The helper always sends the canonical owning checkout to index_repository.
   • Use --mode fast for a smoke index.
   • Installer integrations render scripts/codebase-memory-gateway.py.tmpl with an approved pinned backend path. Replace @@PYTHON_PATH_SHEBANG@@ with the raw absolute interpreter path and replace @@PYTHON_PATH_JSON@@, @@BACKEND_PATH_JSON@@, and @@RESOLVER_PATH_JSON@@ with JSON string literals containing the exact absolute interpreter, backend, and codebase_memory_cache.py paths. The rendered gateway has no upgrade logic and uses execve for pass-through.
   • The gateway guards raw CLI calls only. Zero-argument MCP stdio startup intentionally passes through to the approved backend, so the gateway is not an MCP tool-filtering proxy and does not replace the separate disabled_tools control.
5. Verify the graph.
   • codebase-memory-mcp cli list_projects
   • scripts/codebase-memory-graph.sh schema --repo "$(git rev-parse --show-toplevel)"
   • Run one focused graph query before declaring success.
6. Treat the UI as unavailable.
   • start-ui and keepalive fail closed before configuration or process mutation.
   • UI startup remains disabled until upstream /api/index canonicalization can enforce the same boundary. status may report an already-running grandfathered listener.
7. Audit cache cleanup before applying it.
   • Freeze a host-specific manifest: scripts/codebase-memory-graph.sh cache-audit --manifest /secure/path/cbm-cache.json
   • Built-in reserved roots are ~/.codex/worktrees, ~/GIT/_Worktrees, /tmp, /private/tmp, and any exact .worktrees path component. The audit records normalized lexical and resolved boundary evidence; .worktrees component matching is case-insensitive on Darwin.
   • Missing roots under a reserved boundary are reserved_missing_root candidates. Live valid graphs whose physical canonical root and Git common directory remain reserved are reserved_live_root candidates, including shallow, promisor, and partial clones. Dangling symlinks, bare repositories, non-Git roots, and invalid reserved mappings block as live_root_unmapped.
   • Other missing roots are protected unless the audit names an explicit narrow --ephemeral-prefix.
   • Reserved aliases or linked worktrees that resolve to a nonreserved owner retain duplicate cleanup rules. They require a mapped, registered, final-protected healthy full canonical graph; candidate graphs, reserved graphs, shallow/promisor/partial owners, missing alternate graphs, and ambiguous owners cannot preserve them.
   • When legacy home symlinks name the same physical checkout, preserve the exact canonical graph and treat only the symlink-named graph as a duplicate. Preserve a sole symlink-named graph.
   • Review the manifest, then dry-run it: scripts/codebase-memory-graph.sh cache-prune --manifest /secure/path/cbm-cache.json
   • Manifests with host blockers fail closed by default. After reviewing every relationship, explicitly add --allow-blocked-manifest to preflight and prune only independent candidates while preserving all protected and blocked projects.
   • To retain an exact manifest candidate at runtime, repeat --protect-candidate NAME on cache-prune. Each named candidate must still exist in the unchanged snapshot and pass its root, prefix, classification, canonical mapping, and clone-health rules. It remains in the expected snapshot but is excluded from cache inventory, holder sweeps, DB integrity preflight, final holder probes, and deletion.
   • Runtime candidate protection does not bypass host blockers; add --allow-blocked-manifest independently when blockers were reviewed. Unknown, duplicate, or non-candidate names fail before preflight.
   • Apply only the unchanged manifest: scripts/codebase-memory-graph.sh cache-prune --manifest /secure/path/cbm-cache.json --apply
   • Dry-run and apply freeze regular DB/WAL/SHM fingerprints for every eligible candidate in manifest order, rejecting a missing or size-mismatched DB, nonregular files, and nonzero WAL. Existing absolute paths are swept with /usr/sbin/lsof -nP -F0pfn -f -- in deterministic, NUL-parsed batches before any SQLite open and again after every exact mode=ro&immutable=1 quick_check; global fingerprint equality is required between phases. An absent or zero-byte WAL and a stable regular SHM are allowed. Use prune-only --lsof-timeout-seconds SECONDS to override the 300-second holder timeout within the guarded 30-900 range.
   • Batch holder sweeps are point-in-time checks: they do not prevent a legacy index or server surface from reopening a graph after the check. Unprivileged lsof may not see root-owned or other-user holders, so pruning trusts the point-in-time visibility available to the cache owner; running as root provides stronger holder visibility. Apply processes eligible candidates in manifest order, at most eight per deletion batch and within the same 128 KiB path budget. Each batch revalidates the snapshot and live fingerprints, performs one holder sweep, proves post-sweep fingerprint equality, then revalidates every remaining candidate relationship immediately before the first delete child. The batch launches only codebase-memory-mcp cli delete_project children and verifies registrations plus DB/WAL/SHM absence before continuing; spawn errors, timeouts, nonzero exits, retained registrations, residue, drift, or ambiguous state stop future batches and report launched, verified-deleted, failed, and ambiguous names and bytes.
   • Before applying any manifest containing reserved_live_root, deploy the reserved-root indexing prevention and quiesce every legacy index/server surface outside this helper. The helper reports this operational precondition but does not probe or kill processes.
   • Deletion uses codebase-memory-mcp cli delete_project only. Never remove project databases directly.
8. Report exact proof.
   • Indexed project name.
   • Node and edge counts when available.
   • Any grandfathered UI listener reported by status.
   • For cleanup: manifest path and digest, manifest/eligible/preflighted candidate totals, runtime protected names/reasons/bytes, required operational preconditions, before/after project and byte totals, deleted project names, and any stop condition.
   • Missing binaries, unavailable MCP tools, or incomplete proof.

Inputs

• Repository path.
• Index mode: fast, moderate, full, or cross-repo-intelligence.
• Optional status listener port; default 9749.
• For cache maintenance: a host-local manifest path, optional explicit ephemeral prefixes, and optional exact runtime protected candidate names.

Outputs

• Indexed and queryable repository graph.
• A dry-run cache manifest or guarded CLI-only deletion report.
• Exact status, schema, and proof summary.