git:20260804.2e56cca to git:20260808.c77cb19

# AGENTS.md: review agent guidelines (host-agnostic)

## Plugin architecture

This plugin implements a single principle:

> **The partner reviews, never the host.**

For every review (plan, code, or prompt — all through the single `adversarial-review` skill):

- The agent reading the SKILL.md is the **host**.

- The host **must not** review the host's own work.

- The host runs `lib/call-external.sh` to delegate the heavy critique to the

OTHER agent (the **partner**).

- The host then runs its own independent analysis and **cross-validates**

against the partner's output, tagging findings as `[cross-validated]`,

`[external-only]`, or `[host-only]`.

There is **no haiku courier subagent** in this version. The host (main

session) does both the external dispatch and the synthesis. Removed in the

0.5.0 refactor: the courier added complexity (model inconsistency across

files, blocking-vs-non-blocking ambiguity) without proportionate value.

## Cross-host routing

| Detected host | Partner |

|---------------|--------------------------------------|

| `claude` | Code: direct-xAI Grok 4.5, Codex Luna max, Pi. Plan: Codex Luna max, direct-xAI Grok 4.5, Pi. Then Antigravity |

| `pi` | Codex GPT-5.6 Luna max, then Claude, direct xAI, and the Antigravity ladder |

| `unknown` | Direct xAI, then Pi, then the Antigravity ladder |

Detection happens at every invocation via `lib/detect-host.sh`. See

`references/host-detection.md` for the priority order and the env-leak

asymmetry that drives "Codex env first, Claude env second".

## Anti-recursion contract

`lib/call-external.sh` reads `ADVERSARIAL_REVIEW_DEPTH` (default `0`). If

it sees `≥ 1`, it refuses with exit `1`. Before invoking the partner, it

sets `ADVERSARIAL_REVIEW_DEPTH=1` in the partner's env. So if a launched

partner ever re-triggers this skill, the guard fires. Never disable.

## Critique discipline (v0.8.1+)

- **Stance**: break confidence; do not validate. No credit for intent or likely follow-up.

- **Attack surface**: prioritize expensive failures (auth/trust, data loss, rollback/idempotency, races, degraded deps, migrations, observability gaps).

- **Finding bar**: material only — what fails, why vulnerable, impact, concrete fix. Prefer one strong finding over many weak ones. Clean review with zero findings is valid.

- **Over-engineering**: every plan/code review runs a simplicity counterfactual with required behavior and safety held fixed. Challenge YAGNI, false seams, duplicate ownership, and missed in-repo reuse, including canonical Effect implementations. LOC or framework taste alone is never a finding. An OE finding requires a path/line or plan-section anchor, cited evidence plus material failure/cost/risk, and a simpler alternative that preserves behavior and safety; see `references/output-standards.md`.

- **Focus**: user focus weights the pass; other material issues still report.

- **Summary**: terse ship/no-ship first (≤200 tokens), not a neutral recap.

- Details: `references/codex-lessons.md`, `references/output-standards.md`.

## Output integrity (for synthesis by the host)

Every finding in the final output MUST include:

1. **Severity**: P0 (critical) / P1 (high) / P2 (medium) / P3 (low)

2. **Evidence**: direct quote, file:line reference, or concrete scenario

3. **Impact**: user/data/security/ops consequence

4. **Recommendation**: specific, actionable fix

5. **Confidence**: high | medium | low

6. **Origin tag**: `[cross-validated]` / `[external-only]` / `[host-only]`

(from the cross-validation step)

Do not invent files, lines, or attack chains. Mark inferences.

## Severity scale

| Level | Meaning | Action |

|-------|--------------------------------------------------------|------------------------------|

| P0 | Critical: exploitable, data loss, security breach | Must fix before merge/deploy |

| P1 | High: significant risk, likely failure mode | Should fix in this iteration |

| P2 | Medium: material quality/reliability, limited blast | Fix when convenient |

| P3 | Low: only if still material — not style dump | Optional improvement |

## Fallback chain

See `references/fallback-chain.md`. Order: primary partner -> secondary CLIs

-> quality-first Antigravity ladder -> DEGRADED. **The DEGRADED mode emits an explicit banner** in stdout and

returns exit 2 from `call-external.sh` so the SKILL knows to surface it to

the user.

## Honesty rules

- When a review is clean, say so. Do not manufacture findings.

- When uncertain about severity, use confidence tags.

- When input is ambiguous, ask; don't guess.

- When degraded mode triggers, **always show the banner**. Silent self-review

is the failure mode this plugin was designed to prevent.

## What this plugin does NOT cover

- **Live multi-turn dialog with the partner.** The call is one-shot:

prompt in, analysis out. If you need iteration, the host asks the user;

the user asks the partner directly via the partner's interactive UI.

- **Approval workflows.** This plugin produces critiques, not approvals.

Merge / ship decisions remain the user's.

- **State persistence across calls.** Each `lib/call-external.sh` invocation

is independent. State that needs to persist lives in host memory

(`~/.claude/projects/<cwd>/memory/` or `~/.codex/memories/`).