# Sprint 201 - Reachability Explainability & Replay Evidence

[Reachability Delivery] 201.A) Runtime facts + static callgraph union  
Depends on: Sprint 140 Runtime Signals, Sprint 185 Replay Core, Sprint 186 Scanner Record Mode, Sprint 187 Evidence & CLI Replay  
Summary: Close the explainability gaps by wiring Zastava runtime sampling, Scanner language lifters, Signals scoring, Replay manifests, docs, and test harnesses around the reachbench fixture packs.

Task ID | State | Task description | Owners (Source)
--- | --- | --- | ---
ZASTAVA-REACH-201-001 | TODO | Implement runtime symbol sampling in `StellaOps.Zastava.Observer` (EntryTrace-aware shell AST + build-id capture) and stream ND-JSON batches to Signals `/runtime-facts`, including CAS pointers for traces. Update runbook + config references. | Zastava Observer Guild (`src/Zastava/StellaOps.Zastava.Observer/TASKS.md`)
SCAN-REACH-201-002 | DOING (2025-11-08) | Ship language-aware static lifters (JVM, .NET/Roslyn+IL, Go SSA, Node/Deno TS AST, Rust MIR, Swift SIL, shell/binary analyzers) in Scanner Worker; emit canonical SymbolIDs, CAS-stored graphs, and attach reachability tags to SBOM components. | Scanner Worker Guild (`src/Scanner/StellaOps.Scanner.Worker/TASKS.md`)
SIGNALS-REACH-201-003 | DOING (2025-11-08) | Extend Signals ingestion to accept the new multi-language graphs + runtime facts, normalize into `reachability_graphs` CAS layout, and expose retrieval APIs for Policy/CLI. | Signals Guild (`src/Signals/StellaOps.Signals/TASKS.md`)
SIGNALS-REACH-201-004 | DOING (2025-11-08) | Build the reachability scoring engine (state/score/confidence), wire Redis caches + `signals.fact.updated` events, and integrate reachability weights defined in `docs/11_DATA_SCHEMAS.md`. | Signals Guild · Policy Guild (`src/Signals/StellaOps.Signals/TASKS.md`, `src/Policy/StellaOps.Policy.Engine/TASKS.md`)
REPLAY-REACH-201-005 | DOING (2025-11-08) | Update `StellaOps.Replay.Core` manifest schema + bundle writer so replay packs capture reachability graphs, runtime traces, analyzer versions, and evidence hashes; document new CAS namespace. | BE-Base Platform Guild (`src/__Libraries/StellaOps.Replay.Core/TASKS.md`)
DOCS-REACH-201-006 | TODO | Author the reachability doc set (`docs/signals/reachability.md`, `callgraph-formats.md`, `runtime-facts.md`, CLI/UI appendices) plus update Zastava + Replay guides with the new evidence and operators’ workflow. | Docs Guild (`docs/TASKS.md`)
QA-REACH-201-007 | TODO | Integrate `reachbench-2025-expanded` fixture pack under `tests/reachability/`, add evaluator harness tests that validate reachable vs unreachable cases, and wire CI guidance for deterministic runs. | QA Guild (`tests/README.md`)

> 2025-11-07: reachbench starter + expanded packs staged under repo root; consuming guilds must relocate fixtures into `tests/reachability/fixtures/` as part of QA-REACH-201-007 before enabling CI.