Hardening

Hardening

An unattended approve-your-own-work loop invites specific failure modes. Each is guarded, all cheap.

• Nonce-bound verdict. The critic must end with VERDICT <nonce>: APPROVED|REJECTED, where <nonce> is random per call. The verdict is parsed only from the critic's reply, so a proposer can't approve its own gate by writing VERDICT …: APPROVED into the evidence. Missing / duplicate / wrong-nonce / ambiguous → REJECTED (fail-safe: never auto-approve on doubt). Enforced by lib/verdict_pins.py.
• Grounded critic. Before the LLM call, the critic verifies the files the evidence cites (exists / size / mtime + bounded excerpt) and appends that snapshot, so claims about missing/empty files are visible. Read-only — never executes. Toggle with SPECSTRIDE_CRITIC_GROUNDING (on by default).
• Stale-evidence rule. On REJECT the rejected GATE<N>-EVIDENCE.md is archived before the retry (under attempts/phase<N>/attempt<M>/), so the proposer's file-existence gate isn't instantly satisfied by the old file — which would make "retry" a no-op.
• Single-run lock, timeouts, wall budget, stop.flag. One orchestrator per workdir; a per-pass timeout (SPECSTRIDE_PROPOSER_TIMEOUT) and a per-critic-call timeout (SPECSTRIDE_CRITIC_TIMEOUT); an optional whole-run wall-clock budget (SPECSTRIDE_MAX_WALL_MIN); a manual clean halt via specstride stop.
• Crash-safe resume. The current phase is derived from the GATE* markers on start, not from a stored counter. Kill it anywhere, rerun the same command, it continues. --start-phase N overrides.
• Per-phase git checkpoint. After each GATE<N>-APPROVED, if the workdir is a git repo with changes, the orchestrator commits specstride: phase <N> approved — <title>. Never inits, never pushes. Governed by SPECSTRIDE_GIT_COMMITS (auto).
• Proposer error circuit-breaker. The proposer caps consecutive agent errors so a phase that keeps erroring (e.g. a timeout loop) halts instead of silently bleeding cost per pass. It keys on is_error rather than a subtype, so a hollow "success" that is really an error is caught.

Exit codes

Code	Meaning
0	all phases approved
1	unexpected/internal error
2	MAX_REJECTS exceeded — a human needs to arbitrate
3	invalid spec/config
4	budget exceeded (wall clock or MAX_ITER)
5	lock held by another run
6	stopped via stop.flag (clean; specstride resume or rerun continues). Also produced when the stop lands mid-proposer (specstride stop --now) — earlier versions mislabeled this as 4

Why fail-safe matters here

Every ambiguous signal resolves to REJECTED or halt, never to auto-approve. The whole point of the critic gate is that "I couldn't tell" is treated identically to "no" — the loop would rather stop and ask a human (exit 2) than advance on a verdict it couldn't parse unambiguously.

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