GitNexus/RUNBOOK.md

Runbook — GitNexus

Short, copy-paste operations for local development, MCP, and CI. Commands assume a Unix shell; on Windows use Git Bash or equivalent paths.

Prerequisites

• Node.js ≥ 20 (gitnexus-web/package.json engines).
• Git (analyze requires a git repository).
• From repo root, install and build the CLI package:

cd gitnexus
npm install
npm run build

Use npx gitnexus … from any path after global/published install, or node dist/cli/index.js … when developing from gitnexus/ with a local build.

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Index out of date / “stale” tools

Symptom: MCP or resources warn the index is behind HEAD, or results don’t reflect recent commits.

Fix (from the target repo root):

npx gitnexus analyze

Force full rebuild (same commit but suspect corruption or changed ignore rules):

npx gitnexus analyze --force

Check status:

npx gitnexus status

List what MCP knows about:

npx gitnexus list

Scope extraction incomplete: npx gitnexus status reports incompleteReasons: ["scope-extraction-failed"] when one or more files still lack scope captures after the worker and fallback passes. impact and context then report a lower bound with causes.scopeExtractionFiles set to the affected file count. Re-run npx gitnexus analyze --force; if the reason remains, inspect the scope-extraction warnings for the unsupported or malformed source file. Every pre-existing index remains unverified until it is analyzed once by a version that writes the completeness receipt. An older index or unreadable completeness record reports incompleteReasons: ["scope-extraction-unverified"]; re-analyze it before treating empty impact results as exact.

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Embeddings

First time with vectors (slower, more disk/RAM):

npx gitnexus analyze --embeddings

Important: If you already had embeddings, a plain npx gitnexus analyze preserves them (Non-negotiable 5 in GUARDRAILS.md) — pass --embeddings when you also want vectors generated for new or changed nodes, and --drop-embeddings only for a deliberate wipe. See stats.embeddings in .gitnexus/gitnexus.json (or its legacy meta.json mirror; 0 means none) — but that figure isn't always freshly measured: if a run's embedding-count query can't answer, it carries the previous run's number forward instead of writing a wrong zero. For a certified read, check capabilities.vectorSearch.status instead — it reads unavailable (never a stale count) whenever GitNexus can't vouch for the live vector index.

Partial embedding index (analyze exits 0, but some nodes never got embedded): A long run against a flaky embedding endpoint can finish successfully while a bounded number of sub-batches still fail. Affected nodes are dropped to zero rows (never left half-written) and recorded as a pending embeddingCheckpoint; npx gitnexus status then reports incompleteReasons: ["embedding-checkpoint-pending"]. Recovery is a plain:

npx gitnexus analyze

No --embeddings flag needed — a retained checkpoint forces embedding generation for the pending nodes regardless of flags, and clears once they succeed. --drop-embeddings abandons the pending nodes instead of retrying them; --force also discards the checkpoint (with a warning) and rebuilds without resuming it.

Collapsed graph write (analyze exits NON-ZERO and says INCOMPLETE): A run can finish writing metadata while only a fraction of the relationships it produced are readable back from the index — edges collapsing to a small share of what was built, or a CodeRelation table that never materialized (which reads as a persisted count of zero). Because the metadata IS written and the DB does hold rows, nothing looks broken: queries answer with missing edges rather than an error, which is a confident empty answer rather than a failure. npx gitnexus status reports incompleteReasons: ["graph-write-collapsed"], the analyze summary prints Repository indexed INCOMPLETELY with the expected and persisted counts, and the CLI exits non-zero so automation is not told an unusable index is fine.

Recovery is a full rebuild:

npx gitnexus analyze --force

If it recurs, the cause is almost always environmental rather than a code defect: check free disk space on the volume holding .gitnexus/, make sure no second analyze is running against the same repo (both use .gitnexus/csv for staging), then run npx gitnexus doctor. The check compares in-memory relationship totals (including streamed rows) against what the DB hands back, and is deliberately skipped on incremental runs, where the two counts are not comparable.

Weak semantic recall despite existing embeddings: If paraphrased queries look like keyword-only search, the distance cutoff may be too strict for the embedding model. CLI and MCP query default to 0.6. From the indexed repository, try a broader cutoff:

GITNEXUS_VECTOR_MAX_DISTANCE=0.8 npx gitnexus query "how are expired sessions removed" --limit 10

Compare target inclusion and ranking against the default; a broader cutoff also admits less relevant hits. Set the variable in the MCP/serve launch environment and restart that process when tuning a server. A cutoff change needs no reindex and setting it only during analyze does not persist it. If the index has no vectors, generate embeddings first; if the embedding model or dimensions differ between indexing and querying, align that configuration and regenerate vectors. See Vector cutoff tuning for validation rules and the limited voyage-code-4 evidence from #3457.

Large repos: Analyze may skip or limit embedding work when node counts are very high; watch CLI output.

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MCP: no repos / empty tools

Symptom: GitNexus: No indexed repos yet on stderr when starting MCP.

Fix: In each project you want indexed:

cd /path/to/repo
npx gitnexus analyze

Restart the editor MCP session if needed. The server refreshes the registry lazily; new analyzes are picked up without necessarily reinstalling MCP.

Symptom: Wrong repo when multiple are indexed — pass repo on tools or use list_repos first.

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Clean slate (corrupt or huge .gitnexus)

Current repo only (prompts for confirmation):

npx gitnexus clean

Skip confirmation:

npx gitnexus clean --force

All registered repos:

npx gitnexus clean --all --force

Then re-run npx gitnexus analyze (and --embeddings if you need vectors).

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Local bridge for the web UI

cd gitnexus
npx gitnexus serve
# default http://127.0.0.1:4747 — see serve --help for port/host

Use when the browser UI should talk to local indexed repos instead of WASM-only mode.

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CLI equivalents of MCP tools

Useful for debugging without an editor:

cd gitnexus
npx gitnexus query "authentication flow" --repo MyRepo
npx gitnexus context SomeSymbol --repo MyRepo
npx gitnexus impact SomeSymbol --direction upstream --repo MyRepo
npx gitnexus cypher "MATCH (n) RETURN count(n) LIMIT 1" --repo MyRepo

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CI failures (contributors)

Orchestrator: .github/workflows/ci.yml.

Job	Typical local repro
quality	cd gitnexus && npx tsc --noEmit
unit-tests	cd gitnexus && npx vitest run test/unit
integration	cd gitnexus && npx vitest run test/integration (see workflow matrix for groups)
e2e	Triggered when gitnexus-web/ changes; cd gitnexus-web && E2E=1 npx playwright test (requires gitnexus serve + npm run dev)

Note: Pushes that touch only certain markdown paths may be skipped by paths-ignore in CI — see workflow file for exact patterns.

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Memory / analyze crashes

Analyze re-execs Node with a large old-space heap when needed (analyze.ts). If you still OOM on huge repos, close other processes, avoid --embeddings for a first pass, or analyze a smaller path if supported by your workflow.

Unable to allocate memory / The buffer pool is full during graph writes refers to LadybugDB's native buffer pool. Increasing NODE_OPTIONS, --memory-budget, or worker heap limits does not resize that pool. Recognized pool exhaustion aborts analysis instead of retrying with row skipping.

If the host has enough memory, set an explicit pool size in bytes, then rebuild. For example, 3 GiB is 3221225472 bytes:

GITNEXUS_LBUG_BUFFER_POOL_SIZE=3221225472 npx gitnexus analyze --force

The override bypasses automatic pool sizing. Budget for the Node heap, parse workers, other native allocations, and the OS alongside it; a larger pool can exhaust the host. GITNEXUS_LBUG_BUFFER_POOL_SIZE=0 restores LadybugDB's native 80%-of-RAM default, not an unlimited supply of memory. If memory is insufficient, exclude generated/vendor directories or use a larger host.

A measured graph-write collapse aborts a staged build before publication, leaving the previous index, if any, intact. An in-place run cannot roll back: it records graph-write-collapsed and exits nonzero. Rebuild a previously collapsed index with --force after addressing memory, disk space, or the reported COPY error; do not rely on its incomplete query results.

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LadybugDB / lock errors

Only one process should open a repo's .gitnexus/lbug store at a time. If MCP and a second analyze run conflict, stop one process, then retry analyze or restart MCP.

If the error text is "Only one write transaction at a time is allowed in the system." instead of a lock/busy message, it's the same underlying conflict — our retry matcher (isDbBusyError in src/core/lbug/lbug-config.ts) recognizes this exact string and auto-retries it. The fix if it still surfaces after retries is the same: stop the overlapping process.

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File acquisition/reclaim guard recovery

The portable file-lock backend uses analyze.lock.guard beside analyze.lock. Every acquisition, including an empty slot, exclusively creates the guard before inspecting, reclaiming, creating, and verifying the main lock. It removes the guard before returning a workload handle or waiting on a live workload holder. Linux abstract-socket and Windows named-pipe locking are unchanged.

A stalled or crashed guard owner blocks file acquisition even when its PID is dead, its metadata is incomplete, or no main lock exists. The guard is never automatically stolen. Guard contention times out after at most 30 seconds, capped by the remaining acquisition timeout. This separate ceiling applies even when GITNEXUS_INDEX_LOCK_TIMEOUT_MS is zero or negative (unbounded workload wait). A guard-cleanup failure rejects acquisition; it must not start unprotected work.

Manual recovery is an outage procedure, not an age/PID-based cleanup:

1. Identify the exact lock directory named in the error. This shared primitive also protects group sync and registry operations, not just repo analysis.
2. Stop all relevant writers and prevent restart: editor/agent hooks, watch processes, scheduled jobs, services, and any containers sharing the directory. Account for paused processes and every host with access. If quiescence cannot be established, do not remove the guard. PID metadata is diagnostic only.
3. While restart remains disabled, inspect and preserve the guard/main records for diagnosis, then remove only that directory's orphan analyze.lock.guard and, if present, its orphan analyze.lock. Do not remove databases or sidecars as part of lock recovery. Do not use a recursive or wildcard cleanup.
4. Ensure all participating writers use the guarded version and the same locking backend/domain, then restart in a controlled fashion.

Upgrade requires a coordinated stop/upgrade/restart. Concurrent older versions ignore the guard and can still displace live locks; mixed-version mutual exclusion is not guaranteed. The file protocol assumes reliable atomic local-filesystem O_EXCL creation and cooperating processes. Network/distributed filesystems, external file replacement, and uncoordinated manual deletion are not covered. A process crash while holding the short-lived guard trades automatic recovery for fail-closed safety. Denied file creation returns a non-owning lockFree handle only when neither workload lock nor acquisition guard exists; unreadable paths fail closed. No staging sweep runs without ownership. Analysis, registry transactions, group synchronization, and embeddings sync refuse lockFree handles, including an otherwise up-to-date analysis on a file-backend read-only mount. The socket backend can still acquire ownership on a read-only index mount. Heterogeneous permissions are not proof that another process cannot write.

If guard cleanup fails after this attempt created its workload record, acquisition is refused and token-exact workload cleanup is attempted before returning the error. Failed or unverifiable cleanup must be diagnosed under the same quiesced recovery procedure above; never delete a possibly active successor's record.

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Where to dig deeper

• Architecture overview: ARCHITECTURE.md
• Agent safety rules: GUARDRAILS.md
• Tests: TESTING.md