gbrain/docs/eval-bench.md

Running real-world eval benchmarks against your gbrain changes

Audience: gbrain maintainers and contributors. If you're touching retrieval (search, ranking, embeddings, intent classification, query expansion, source boost, hybrid fusion), this is the doc.

For the NDJSON wire format consumed by gbrain-evals, see eval-capture.md. This doc is the human dev loop that lives on top of that format.

Prerequisite: turn on contributor mode

Capture is off by default for production users (privacy-positive — no surprise data accumulation). Contributors flip it on with one line:

# In ~/.zshrc or ~/.bashrc:
export GBRAIN_CONTRIBUTOR_MODE=1

Verify:

gbrain query "anything" >/dev/null
psql $DATABASE_URL -c 'SELECT count(*) FROM eval_candidates'   # should be > 0

To override (force on/off regardless of env var), edit ~/.gbrain/config.json:

{"eval": {"capture": true}}    // force on
{"eval": {"capture": false}}   // force off

Explicit config beats the env var both directions.

The 4-command loop

# ① Capture: writes to eval_candidates whenever CONTRIBUTOR_MODE is set.
#   Inspect what's been collected:
gbrain doctor                                     # surfaces capture failures
psql $DATABASE_URL -c 'SELECT count(*) FROM eval_candidates'

# ② Snapshot: freeze a baseline before your code change.
gbrain eval export --since 7d > baseline.ndjson

# ③ Code change: do whatever you want — tune RRF_K, swap embed model, edit
#    hybrid.ts, add a new boost source, change the intent classifier.

# ④ Replay: re-run every captured query against the current build.
gbrain eval replay --against baseline.ndjson

Output:

Replaying 247 captured queries…
  ...25/247
  ...50/247
  ...
Replayed 247 of 247 captured queries (0 skipped, 0 errored)
Mean Jaccard@k:    0.927
Top-1 stability:   91.5%
Mean latency Δ:    +14ms (current vs captured)

Top 5 regression(s):
  jaccard=0.20  captured=12  current=3   "find every reference to widget-co"
  jaccard=0.43  captured=14  current=8   "show me everything tagged for review"
  jaccard=0.50  captured=8   current=4   "what did alice say about the spec"
  ...

Three numbers tell you whether the change is safe to land:

Metric	What it means	Healthy range
Mean Jaccard@k	Average overlap between captured retrieved slugs and current run's slugs. 1.0 = identical sets.	≥0.85 for "neutral" changes. <0.7 means major retrieval shift.
Top-1 stability	Fraction of queries whose #1 result didn't change.	≥85% for tuning passes. <70% means top-of-funnel broke.
Mean latency Δ	Current minus captured. Positive = slower now.	Within ±50ms of captured. >2× anywhere = regression alarm.

What it actually does

gbrain eval replay reads your NDJSON snapshot and, for each row:

1. Re-executes the same op (searchKeyword for tool_name='search', hybridSearch for tool_name='query') with the captured detail and expand_enabled values threaded back in.
2. Captures the current retrieved_slugs (deduped, in result order).
3. Computes set-Jaccard between captured and current slug sets.
4. Records top-1 match (was the #1 result the same slug?).
5. Records latency delta vs captured latency_ms.

It does NOT compute MRR or nDCG — those need ground-truth relevance labels, not a baseline comparison. For metric-against-truth eval, use gbrain eval --qrels <path> (the legacy IR-eval path, still supported). The replay tool answers a different question: "did my code change move retrieval, and which queries did it move most?"

For a third evaluation axis — public benchmark, ground-truth labels, full question-answer pipeline (not just retrieval) — gbrain eval longmemeval <dataset.jsonl> (v0.28.8) runs the LongMemEval benchmark against gbrain's hybrid retrieval. Each question gets a clean in-memory PGLite, its haystack imported, the question asked, the hypothesis emitted as JSONL — exactly the shape LongMemEval's evaluate_qa.py consumes. Your ~/.gbrain brain is never opened. See ## Public benchmarks: LongMemEval below.

Best-effort by design

Replay is not pure. Three things can drift between capture and replay:

1. Brain state — your brain probably has more pages now than when the snapshot was taken. Unless you explicitly seed a fixed corpus, mean Jaccard will drop simply because new pages are eligible.
2. Embedding source — if you changed OPENAI_API_KEY between capture and replay (or the embedding model rotated), vector-path results drift even with identical code.
3. Capture cap — captured retrieved_slugs is a deduped set; it doesn't preserve internal ranking metadata. Two tools can return the same slug set with different scores — Jaccard will say 1.0, but a downstream consumer that orders by score may behave differently.

The metrics are regression alarms on real queries, not a hash check. Pair them with manual inspection of the top regressions.

Cost

Every query row in the snapshot embeds the query string via OpenAI to run the vector half of hybridSearch. Cost is identical to a normal gbrain query invocation — text-embedding-3-large at OpenAI list price, batched inside a single replay row.

If you're iterating locally and don't want to pay per change, use --limit 50 to cap rows replayed. The 50 most recent rows are usually enough to catch direction; expand for the final pre-merge run.

# Iteration mode — 50 most recent queries
gbrain eval replay --against baseline.ndjson --limit 50

# Pre-merge — full snapshot
gbrain eval replay --against baseline.ndjson --top-regressions 20

CI integration

gbrain eval replay --against baseline.ndjson --json > replay.json
jq -e '.summary.mean_jaccard >= 0.85' replay.json || exit 1
jq -e '.summary.top1_stability_rate >= 0.85' replay.json || exit 1

Stable JSON shape (schema_version: 1):

{
  "schema_version": 1,
  "summary": {
    "rows_total": 247,
    "rows_replayed": 247,
    "rows_skipped": 0,
    "rows_errored": 0,
    "mean_jaccard": 0.927,
    "top1_stability_rate": 0.915,
    "mean_latency_delta_ms": 14,
    "rows_over_2x_latency": 0
  }
}

--verbose adds a results: [...] array with one entry per replayed row (useful for piping into jq or a notebook for deeper analysis).

When to run this

Before merging anything that touches:

• src/core/search/hybrid.ts (RRF, fusion, dedup, two-pass retrieval)
• src/core/search/source-boost.ts / sql-ranking.ts (per-source ranking)
• src/core/search/intent.ts (auto-detail classification)
• src/core/search/expansion.ts (Haiku query expansion)
• src/core/search/dedup.ts (cross-page result collapse)
• src/core/embedding.ts or any embedding model swap
• src/core/operations.ts query or search op handlers (capture surface)
• src/core/postgres-engine.ts / pglite-engine.ts searchKeyword / searchVector SQL

Skip for: schema-only migrations, doc changes, tests-only PRs, CLI ergonomics that don't touch retrieval.

Building your own corpus

If you don't have captured traffic yet (fresh install, can't dogfood for a week before merging), you can hand-author an NDJSON file:

{"schema_version":1,"id":1,"tool_name":"query","query":"who is alice","retrieved_slugs":["people/alice","people/alice-bio"],"expand_enabled":false,"detail":null,"latency_ms":0,"remote":false}
{"schema_version":1,"id":2,"tool_name":"search","query":"acme deal","retrieved_slugs":["deals/acme-seed","companies/acme"],"latency_ms":0,"remote":false}

Then run gbrain eval replay --against handcrafted.ndjson to confirm the authoritative slugs come back. This is the seam between the BrainBench-Real pipeline (replay against live captures) and the BrainBench fixed-fixture pipeline (gbrain eval --qrels with the sibling gbrain-evals corpus).

Off-switch

Two ways to disable capture:

unset GBRAIN_CONTRIBUTOR_MODE             # easy: just unset the env var

Or force off regardless of the env var via ~/.gbrain/config.json:

{"eval": {"capture": false}}

Existing eval_candidates rows stay until you gbrain eval prune --older-than 0d (or just drop the table).

Failure modes

What you see	What it means
Mean Jaccard@k: 0.4, top regressions all in one source dir	Source boost or hard-exclude regression on that prefix
Top-1 stability: 30%, mean Jaccard still high	RRF tuning shifted the rank order without changing the set — re-tune rrfK
Mean latency Δ: +500ms, jaccard high	Vector path got slower; check embedding API or HNSW probes
rows_errored > 0	One or more queries threw. Inspect first 3 in human output, or --json to see all error_message fields
Many skipped: empty query	Capture ran on rows where someone passed empty query — check why those were captured

Public benchmarks: LongMemEval (v0.28.8)

gbrain eval longmemeval runs the public LongMemEval benchmark directly against gbrain's hybrid retrieval. Different evaluation axis from eval replay: public dataset with ground-truth labels, end-to-end question-answer pipeline, hermetic per-question brains.

# Download the dataset (visit the HF page in a browser; gated/manual download).
# Place longmemeval_oracle.json (or _s.json) somewhere local.

# Retrieval-only (no LLM answer-gen, fastest path, no Anthropic key needed):
gbrain eval longmemeval ./longmemeval_oracle.json --limit 50 --retrieval-only \
  > /tmp/hypothesis.jsonl

# Full pipeline (Anthropic key required for answer-gen):
gbrain eval longmemeval ./longmemeval_oracle.json --limit 50 \
  > /tmp/hypothesis.jsonl

# Score with LongMemEval's published evaluate_qa.py (not bundled — needs
# OpenAI gpt-4o per their spec):
python evaluate_qa.py /tmp/hypothesis.jsonl

Architecture (read this if you're touching the harness)

• One in-memory PGLite per benchmark run via createBenchmarkBrain + withBenchmarkBrain. Your ~/.gbrain is never opened.
• Between questions: TRUNCATE over runtime-enumerated pg_tables, NOT a hardcoded list — schema migrations don't silently leak data across questions. Infrastructure tables (sources, config, gbrain_cycle_locks, subagent_rate_leases) are preserved across resets.
• Sanitization parity: re-uses INJECTION_PATTERNS from src/core/think/sanitize.ts so adding a new injection pattern automatically covers takes AND benchmarks. One source of truth.
• Retrieved chat content is wrapped in <chat_session id="..." date="..."> framing; the answer-gen system prompt declares the content UNTRUSTED. Same posture as <take> framing.
• LLM injection seam: runEvalLongMemEval(args, {client?: ThinkLLMClient}). Tests stub the client so the full pipeline runs hermetically without any API key.

Flags

Flag	Default	Purpose
--limit N	run all	Cap question count (iterate fast)
--retrieval-only	off	Emit retrieved chunks; no LLM answer-gen
--keyword-only	off	Disable vector path (debug retrieval issues)
--expansion	off	Multi-query expansion. Off by default for determinism (no per-query Haiku call). Pass to opt in.
--top-k K	10	Retrieval depth
--model M	resolved	Default resolves through resolveModel() 6-tier chain (models.eval.longmemeval config key)
--output FILE	stdout	Write hypothesis JSONL to file instead of stdout

Numbers

p50 25.9ms / p99 30.3ms warm reset+import+search on Apple Silicon (per the test/eval-longmemeval.test.ts perf gate). Per-question cost well under the 500ms speed gate. 500 questions = ~13s of overhead plus your retrieval and LLM latency.

Measuring brain consistency over time (v0.32.6)

gbrain eval suspected-contradictions is a complementary measurement instrument: it samples retrieval results for unmarked semantic contradictions (e.g., compiled_truth vs chat content, intra-page chunk vs active take). Where LongMemEval measures retrieval correctness on a fixed labeled set, the contradiction probe measures how often a real brain surfaces conflicting answers.

Recommended nightly cadence

# Once a day, against your top 50 most-frequent queries:
gbrain eval suspected-contradictions \
  --queries-file ~/.gbrain/queries.jsonl \
  --top-k 5 \
  --budget-usd 5 \
  --output ~/.gbrain/probe-runs/$(date +%Y-%m-%d).json

Persistent cache (eval_contradictions_cache) makes re-runs near-zero cost until you bump PROMPT_VERSION. Trend-track via:

gbrain eval suspected-contradictions trend --days 30

The ASCII bar chart shows total flagged per day. Headline % surfaces in gbrain doctor's contradictions check with paste-ready resolution commands per high-severity finding.

See also

• docs/contradictions.md — architecture, severity rubric, action criteria.
• CHANGELOG ## [0.32.6] — full release notes including the bigger-swing decision criteria gated on Wilson CI lower-bound.

v0.40.1.0 Track D — Eval infrastructure

Three eval surfaces grew non-trivial capabilities in v0.40.1.0. This section covers the dev loop that uses them and the gates they enforce.

gbrain eval longmemeval --by-type — per-question-type R@k breakdown

LongMemEval has always computed per-question-type recall internally; v0.40.1.0 surfaces it in machine-readable form. Two additive changes:

1. Every per-question JSONL row now includes a question: string field so the gbrain eval cross-modal --batch consumer (below) can read it without joining back against the source dataset.
2. New --by-type flag emits a final aggregate line keyed by question_type:

{"schema_version": 1, "kind": "by_type_summary",
 "recall_by_type": {"single-session-user": {"hit": 18, "total": 19, "rate": 0.947}},
 "aggregate": {"hit": 110, "total": 120, "rate": 0.917}}

Resume-safe. When --resume-from is the same path as --output, the summary is rebuilt from the file (each per-row includes question_type and recall_hit) so the final aggregate covers all resumed questions, not just this run's slice. The prior summary at the file tail is replaced, not appended — a brain that resumes 5 times across a 500-question run ends with exactly ONE summary at the tail.

Optional gate. --by-type-floor 0.85 exits non-zero when any question_type's rate falls below 0.85. Default: informational only.

# Diagnose per-type ranking quality after a search-touching change.
gbrain eval longmemeval ~/datasets/longmemeval_s.jsonl \
  --by-type --output /tmp/run.jsonl
tail -1 /tmp/run.jsonl | jq .   # summary line

# Strict gate in a CI script.
gbrain eval longmemeval test/fixtures/longmemeval-mini.jsonl \
  --by-type --by-type-floor 0.80 --output /tmp/run.jsonl
echo "exit=$?"  # 1 if any type fell below 0.80

Hermetic retrieval gate — test/eval-replay-gate.test.ts

The v0.40.1.0 Track D structural fix for "PRs touching src/core/search/ silently regress retrieval." Replaces the original "replay against captured eval_candidates" design (which Codex caught as non-functional in CI — see the v0.41+: contributor-mode CI capture TODO in TODOS.md for the deferred real-query version).

How it works:

• Hand-curated qrels fixture at test/fixtures/eval-baselines/qrels-search.json with PLACEHOLDER names only (no real people / companies per CLAUDE.md privacy rule).
• The test seeds a PGLite engine with synthetic pages whose embeddings are basis vectors (the same basisEmbedding(idx) pattern as test/e2e/search-quality.test.ts). No API keys, no DATABASE_URL.
• For each qrels query, calls engine.searchVector(basisEmbedding(dim)) and computes top1_match_rate and recall@10. Asserts both meet floors (>= 0.80 and >= 0.85 by default).
• Lives in the unit-shard test matrix (.github/workflows/test.yml) so it runs on every PR via bun test, NOT in the E2E fixed-file workflow.

Refreshing the qrels fixture (the Why: discipline, D4)

When CI fails because a legitimate ranking change moved expected slugs, the fix is to edit qrels-search.json directly. Always include a Why: line in the commit body so future maintainers can read the audit trail. Without the Why:, the gate degrades to a rubber stamp within months. The convention is informational (not a commit-hook block), but enforce it in PR review.

Example commit body:

chore(eval): refresh qrels for new source-boost ordering

Why: v0.40.x source-boost now weights originals/ over concepts/, so
q12 (founder-mode) now correctly surfaces originals/founder-mode-example
top-1. Manual verification: ran the production query; new ranking is
clearly better-aligned with the query intent.

Env-overrides for floors

GBRAIN_REPLAY_GATE_TOP1_FLOOR=0.85 \
GBRAIN_REPLAY_GATE_RECALL_FLOOR=0.90 \
  bun test test/eval-replay-gate.test.ts

Use to tighten or loosen the gate as the qrels fixture matures.

gbrain eval cross-modal --batch — batch quality scoring

Single-task cross-modal eval scores one (task, output) pair. Batch mode runs the same scoring over an entire LongMemEval JSONL output, with cost guardrails.

# Step 1: produce LongMemEval hypotheses (real cost: depends on model + N).
gbrain eval longmemeval ~/datasets/longmemeval_s.jsonl \
  --limit 10 --output /tmp/run.jsonl

# Step 2: batch-score those hypotheses (real cost: ~$0.70 for 10 questions,
# 1 cycle, 3 model slots at default --max-usd 5 budget cap).
gbrain eval cross-modal --batch /tmp/run.jsonl \
  --limit 10 --cycles 1 --concurrent 3 --max-usd 5 --json
echo "exit=$?"  # 0=all-pass, 1=any-fail, 2=any-error-or-inconclusive

Key behaviors:

• Default --cycles 1 in batch mode (single-task default is 3 in TTY) to bound cost. Pass --cycles 3 to match single-task strictness.
• --concurrent 3 runs up to 3 questions in parallel x 3 model slots each = 9 simultaneous API calls. Below tier-1 rate limits for all three providers.
• --max-usd FLOAT refuses to start if the pre-flight cost estimate exceeds the cap, unless --yes bypasses (required for non-interactive cron / CI).
• Filters kind: "by_type_summary" rows automatically (the LongMemEval --by-type summary line is metadata, not a question).
• --batch is mutually exclusive with --task; fail-fast usage error if both are set.
• Exit precedence (fail-loud): ERROR > FAIL > INCONCLUSIVE > PASS.
• Per-question receipts land in a tempdir and are deleted at end of batch; the summary inlines per-question verdicts so the audit trail is self-contained.

Nightly cross-modal quality probe (opt-in, autopilot)

src/core/cycle/nightly-quality-probe.ts ships a phase that runs the longmemeval

• cross-modal pipeline once per 24h. Disabled by default to avoid surprise API spend. Enable per-host:

gbrain config set autopilot.nightly_quality_probe.enabled true
gbrain config set autopilot.nightly_quality_probe.max_usd 5.00   # optional override

Note: --phase nightly_quality_probe wiring into the autopilot scheduler is deferred to a v0.41+ follow-up (see TODOS.md). For now the phase is callable in isolation; the test harness exercises it via DI stubs.

# Manual smoke (exercises the path via DI stubs, no real API spend).
bun test test/nightly-quality-probe.test.ts

Observability:

• ~/.gbrain/audit/quality-probe-YYYY-Www.jsonl — one event per run with outcome (pass / fail / inconclusive / error / budget_exceeded / rate_limited / no_embedding_key), pass/fail/inconclusive/error counts, est_cost_usd, fixture_sha8. ISO-week rotation (mirrors slug-fallback audit).
• gbrain doctor surfaces nightly_quality_probe_health:
  • SKIPPED (disabled) — with paste-ready enable command.
  • OK (enabled, no events yet) — autopilot hasn't fired its first run.
  • OK (last 7d all PASS) — with timestamp of latest run.
  • WARN — any FAIL / ERROR / BUDGET_EXCEEDED in the window, with outcome counts and the latest run's reason.

Real expected cost: ~$0.35 per nightly run (5 questions x 3 slots x 1 cycle x ~$0.02/call) ≈ $10.50/month. Worst-case under the default budget cap: $150/month. Opt-in default prevents discovering this in your card statement.