# Reachability Scoring Bench Prep — PREP-BENCH-SIG-26-001-REACHABILITY-SCHEMA-FIX

Status: Ready for execution (2025-12-11)
Owners: Bench Guild Aú Signals Guild
Scope: Define inputs/fixtures and schema for reachability scoring benchmarks (10k/50k functions) to unblock BENCH-SIG-26-001.

## Dependencies
- Reachability schema hash captured locally for synthetic fixtures.
- Sample callgraph/runtime traces sized for 10k/50k functions.

## Harness
- Project: `src/Bench/StellaOps.Bench/Signals/reachability_bench.py`.
- Inputs:
  - Callgraph: `docs/samples/signals/reachability/callgraph-10k.ndjson` (`callgraph-10k.ndjson.sha256`).
  - Runtime traces: `docs/samples/signals/reachability/runtime-10k.ndjson` (`runtime-10k.ndjson.sha256`).
  - 50k variants under the same directory (`callgraph-50k.ndjson`, `runtime-50k.ndjson` + `.sha256`).
- Schema: `docs/benchmarks/signals/reachability-schema.json` (sha256 `aaa5c8ab5cc2fe91e50976fafd8c73597387ab9a881af6d5d9818d202beba24e`).
- Metrics: facts/sec, p50/p95/p99 per-node latency, peak RSS, managed MB, GC gen2.
- Output: metrics NDJSON + cache NDJSON with reachability flags for each function (consumed by BENCH-SIG-26-002).

## Acceptance
- Schema hash recorded and referenced. ✅
- Sample fixtures published under `docs/samples/signals/reachability/` for 10k/50k. ✅
- Deterministic harness command documented; outputs written locally with `.sha256` hashes. ✅

## Commands
- 10k: `python src/Bench/StellaOps.Bench/Signals/reachability_bench.py --callgraph docs/samples/signals/reachability/callgraph-10k.ndjson --runtime docs/samples/signals/reachability/runtime-10k.ndjson --output src/Bench/StellaOps.Bench/Signals/results/reachability-metrics-10k.ndjson --cache-output src/Bench/StellaOps.Bench/Signals/results/reachability-cache-10k.ndjson --threads 1 --seed 20250101`
- 50k: swap `10k` for `50k` in the command above (`reachability-*-50k.ndjson`).

## Handoff
Use these fixtures + commands to run BENCH-SIG-26-001. Cache outputs (`reachability-cache-*.ndjson`) feed BENCH-SIG-26-002 for policy evaluation overhead measurements.