pre-mortem

---

name: pre-mortem description: 'Stress-test plans before work. Use when: a plan is drafted but not yet executed and you want to surface failure modes, risks, and what would prove it wrong before committing.' practices:

• adr
• mythical-man-month
• design-by-contract hexagonal_role: domain consumes:
• standards produces:
• result.json
• verdict.json context_rel:
• kind: shared-kernel with: standards skill_api_version: 1 metadata: tier: judgment dependencies:
  • council context: window: fork intent: mode: task sections: exclude:
    • HISTORY intel_scope: full output_contract: skills/council/schemas/verdict.json

---

Pre-Mortem Skill

Purpose: Is this plan/spec good enough to implement?

Mandatory for 3+ issue epics. Pre-mortem is enforced by hook when /crank is invoked on epics with 3+ child issues. 6/6 consecutive positive ROI. Bypass: --skip-pre-mortem flag or AGENTOPS_SKIP_PRE_MORTEM_GATE=1.

Loop position

Pre-flight check between moves 3 (slice plan) and 4 (TDD per slice) of the operating loop. Consumes the slice validation plan; produces a PASS/WARN/FAIL verdict on the plan AND on the wave-validity rows (distinct write scopes, no shared migration/contract/CLI surface, owner per slice, discard path per slice). A wave can only be claimed parallel if pre-mortem confirms every conflict-free row. FAIL on wave-validity → run slices sequential or send the plan back to /plan for re-slicing.

Run /council validate on a plan or spec to get multi-model judgment before committing to implementation.

---

Quick Start

/pre-mortem                                         # validates most recent plan (inline, no spawning)
/pre-mortem path/to/PLAN.md                         # validates specific plan (inline)
/pre-mortem --deep path/to/SPEC.md                  # 4 judges (thorough review, spawns agents)
/pre-mortem --mixed path/to/PLAN.md                 # cross-vendor (Claude + Codex)
/pre-mortem --preset=architecture path/to/PLAN.md   # architecture-focused review
/pre-mortem --explorers=3 path/to/SPEC.md           # deep investigation of plan
/pre-mortem --debate path/to/PLAN.md                # two-round adversarial review

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Execution Steps

Step 0: Bead-Input Pre-Flight (Mandatory)

When the input to /pre-mortem is a bead ID (matches pattern [a-z]{2,6}-[0-9a-z.]+) AND complexity is "full" OR the bead is older than 7 days OR the bead description was filed by a prior session, automatically run ao beads verify <bead-id> as the very first action. If verify reports any STALE citations, present them to the user and ask for scope re-validation before proceeding. This implements the shared stale-scope validation rule.

Step 1: Find the Plan/Spec

If path provided: Use it directly.

If no path: Find most recent plan:

ls -lt .agents/plans/ 2>/dev/null | head -3
ls -lt .agents/specs/ 2>/dev/null | head -3

Use the most recent file. If nothing found, ask user.

Step 1.4: Retrieve Prior Learnings & Compiled Prevention (Mandatory)

Run ao lookup for the plan's domain, then load compiled checks from .agents/pre-mortem-checks/*.md (fall back to .agents/findings/registry.jsonl). Include matched entries in the council packet as known_risks and record ao metrics cite influence. Full contract (fail-open rules, section-evidence handling, ranking heuristics, citation lifecycle) in references/compiled-prevention.md. This file also contains Step 1a (flywheel search, skipped under --quick) and Step 1b (PRODUCT.md auto-include).

Fail-open reader behavior is mandatory: missing or empty compiled prevention inputs skip silently; malformed line -> warn and ignore that line; unreadable file -> warn once and continue without findings.

Step 1a: Flywheel Search (Skip if --quick)

Run the flywheel search from references/compiled-prevention.md unless --quick is active.

Step 1b: PRODUCT.md Context (Skip if --quick)

When PRODUCT.md exists and full council mode is active, add one product judge: 3 judges total (2 plan-review + 1 product).

Step 1.5: Fast Path (--quick mode)

By default, pre-mortem runs inline (--quick) — single-agent structured review, no spawning. This catches real implementation issues at ~10% of full council cost (proven in ag-nsx: 3 actionable bugs found inline that would have caused runtime failures).

In --quick mode, skip Steps 1a and 1b as standalone pre-processing phases. If PRODUCT.md exists, Step 1b's product context is still loaded inline during the quick review. --deep, --mixed, --debate, and --explorers add the dedicated product perspective and wider council fan-out.

To escalate to full multi-judge council, use --deep (4 judges) or --mixed (cross-vendor).

Step 1.5.1: Reversibility self-check — size the gate to the stakes (Mandatory)

Before selecting gate depth, state the plan's blast radius and reversibility in one sentence. If the plan is reversible (content recoverable, deletion non-destructive, no shared schema/CLI/contract/migration surface), say so and default to the lightest gate — inline --quick plus a single blind sub-agent for the no-self-grading floor (Step 2.9). Escalate to --deep / --mixed / full council only on a named irreversible surface — a one-way door per the blast-radius rule (schema migration, public API, architecture fork, security posture, deletion, mutate-shared-trunk). This is the de-escalation dual of Step 2.10's escalation rule: 2.10 says add rigor for one-way doors; this says notice and drop rigor when the op is reversible. Running a cross-family duel on a reversible doc/refactor is the waterfall the ratchet exists to avoid.

Step 1.6: Scope Mode Selection

Determine review posture — EXPANSION, HOLD SCOPE, or REDUCTION — and commit scope_mode: <expansion|hold|reduction> in the council packet. Auto-detection rules and mode-specific judge prompts are in references/scope-mode.md.

Step 1.7: Load Council FAIL Patterns (Mandatory)

Read references/council-fail-patterns.md for the top 8 council FAIL patterns to check against. These patterns are derived from 124 analyzed FAIL verdicts across 946 council sessions. They apply to both --quick and --deep modes.

Step 2: Run Council Validation

Default (inline, no spawning):

/council --quick validate <plan-path>

Single-agent structured review. Catches real implementation issues at ~10% of full council cost. Sufficient for most plans (proven across 6+ epics).

Default (2 judges with plan-review perspectives) applies when you intentionally run non-quick council mode.

With --deep (4 judges with plan-review perspectives):

/council --deep --preset=plan-review validate <plan-path>

Spawns 4 judges:

• missing-requirements: What's not in the spec that should be? What questions haven't been asked?
• feasibility: What's technically hard or impossible here? What will take 3x longer than estimated?
• scope: What's unnecessary? What's missing? Where will scope creep?
• spec-completeness: Are boundaries defined? Do conformance checks cover all acceptance criteria? Is the plan mechanically verifiable?

Use --deep for high-stakes plans (migrations, security, multi-service, 7+ issues).

With --mixed (cross-vendor):

/council --mixed --preset=plan-review validate <plan-path>

3 Claude + 3 Codex agents for cross-vendor plan validation with plan-review perspectives.

With explicit preset override:

/pre-mortem --preset=architecture path/to/PLAN.md

Explicit --preset overrides the automatic plan-review preset. Uses architecture-focused personas instead.

With explorers:

/council --deep --preset=plan-review --explorers=3 validate <plan-path>

Each judge spawns 3 explorers to investigate aspects of the plan's feasibility against the codebase. Useful for complex migration or refactoring plans.

With debate mode:

/pre-mortem --debate

Enables adversarial two-round review for plan validation. Use for high-stakes plans where multiple valid approaches exist. See /council docs for full --debate details.

Steps 2.4–2.8: Mandatory Council Checks

Five mandatory checks run during council validation — temporal interrogation, error-&-rescue map, council FAIL pattern check, test pyramid coverage, and input validation for enum-like fields. Each has auto-trigger conditions and judge-prompt snippets. Full step text and check tables in references/mandatory-checks.md.

When a plan introduces a regex, grep, glob, or similar scope predicate, also apply references/scope-predicate-positive-negative-cases.md: require positive and negative examples before approval.

Re-baseline against what exists (mandatory when the plan proposes NEW construction). A plan that says "build X" / "X is missing" / "the unbuilt arm" must prove X does not already exist — grep/read the codebase for the capability, the command, the function, the table — before the effort estimate is accepted. The dominant scoping failure is estimating new construction for machinery that is already built (and only needs integration), which inflates effort 2× and risks a duplicate/competing implementation. Judge prompt: "For each 'build/add/missing' claim, was the absence verified by a search, or assumed? Name the search." Treat an unverified "it's missing" as a WARN at minimum; FAIL if the plan's effort/sequencing depends on it.

Step 2.9: No-self-grading invariant (author ≠ validator)

The pre-mortem verdict must NOT be graded by the plan's own author. A verdict produced by the authoring context is autocorrelated — the same assumptions that shaped the plan pass it. This is the no-self-grading invariant (ag-lmdx.4): the independent-trust-domain check on the plan-acceptance verdict.

Rule: the judge context MUST be distinct from the author context. Validation MAY run inside the authoring session, but the judge MUST be a blind sub-agent — a fresh, context-isolated agent acting as if it has no authoring context. Record judge_id (the isolated sub-agent context) distinct from author_id (the planning context). The --deep/--mixed council judges satisfy this when they are context-isolated sub-agents; an inline self-review by the planning agent does NOT.

Refuse to emit a PASS verdict when the judge context equals the author context (judge_id == author_id) — re-run the verdict through a blind sub-agent judge instead.

Escape: --allow-self (default OFF) waives the invariant for the inline fallback only (e.g. no sub-agent runtime available). Using it stamps the verdict as self-graded; downstream ao turn verify reports it as waived, not independently validated.

Enforcement: ao turn verify <bead> evaluates the author_neq_validator predicate from the turn-input file's author_id/judge_id and fails the Evidenced-Turn DoD on a self-graded verdict unless --allow-self is passed.

Cross-family requirement for one-way-door plans: when the plan is a strategy, experiment, or one-way-door decision, the judge MUST be from a different model family than the author (e.g. author=Claude → judge=Codex, or vice versa). Same-family judges share training-data-correlated blind spots — the dominant failure mode for high-stakes plan review. Use --mixed or codex exec to satisfy this. Record judge_family in the verdict alongside judge_id.

Step 2.10: Pre-Registered Decision Rule (strategy / experiment / one-way-door plans)

When the plan under review is a strategy, experiment-driven plan, or a one-way-door decision (irreversible: schema migration, public API change, architecture fork, security posture change, data deletion), the pre-mortem MUST require and record a pre-registered decision rule — defined BEFORE the council judges deliberate.

A pre-registered decision rule answers three questions:

1. What result changes the decision? Name the specific finding, metric, or evidence that would cause the plan to be rejected or materially altered. (Not "if judges say FAIL" — that's tautological.)
2. What threshold or CI gate kills the claim? Name a concrete, mechanically verifiable condition: a test that must pass, a metric that must stay within bounds, a property that must hold. If no such gate exists, the plan is unfalsifiable — FAIL.
3. What negative result redirects? Name what happens on a real negative: pivot to alternative X, defer to next cycle, escalate to human. "Try harder" is not a redirect.

Record the decision rule in the council packet frontmatter as decision_rule: before judges deliberate. Judges evaluate the plan AGAINST the decision rule — not just "is this plan good" but "does this plan survive its own kill conditions."

Why: without a pre-registered decision rule, pre-mortem degenerates into "does this plan seem reasonable" — a question the author already answered yes to. The decision rule makes the pre-mortem falsifiable. Surfaced by a cross-family (Codex) pre-mortem that found real problems an inline review missed because the inline review had no kill conditions to test against.

Step 2.11: Plan-Pawl Duel Checklist (the cross-family invariant)

Steps 2.9 + 2.10 are one invariant — a plan's acceptance verdict must come from an independent, cross-family adversary, against pre-registered kill conditions. That invariant has two delivery forms of the same thing, not two different gates:

• /pre-mortem --mixed (this skill) — a cross-vendor council judges the plan artifact.
• The discovery plan-pawl duel (discovery STEP 3.5 → ao plan-pawl decide, the plan-pawl row) — two distinct-family judge panes duel over the SynthesisPacket; that duel verdict IS the pre-mortem verdict for fanout-class discovery (do not run a second council).

For fanout class the duel satisfies no-self-grading by construction: the two judges are fresh, context-isolated, distinct-family panes, so author_id ≠ judge_id and judge_family ≠ author_family hold automatically. Before accepting ANY plan acceptance verdict (either form), check:

• Independent judge — judge_id ≠ author_id (no inline self-review; --allow-self waives only for the no-subagent fallback, and stamps the verdict self-graded).
• Cross-family for one-way doors — strategy / experiment / irreversible plan ⇒ judge_family ≠ author_family (≥2 distinct roster families; the duel's quorum floor).
• Pre-registered decision rule — decision_rule: recorded BEFORE deliberation; judges evaluate the plan against its own kill conditions.
• Not a behavior substitute — the plan-pawl gates plan SHAPE; it never replaces the acceptance-test layer (2026-06-12 auth-bypass learning).

Step 3: Interpret Council Verdict

Council Verdict	Pre-Mortem Result	Action
PASS	Ready to implement	Proceed
WARN	Review concerns	Address warnings or accept risk
FAIL	Not ready	Fix issues before implementing

Step 4: Write Pre-Mortem Output

Write to .agents/council/YYYY-MM-DD-pre-mortem-<topic>.md using the full template (frontmatter, verdict table, pseudocode-fix format, decision gate) in references/write-pre-mortem-output.md. That reference also contains Step 4.5 (persist reusable findings to .agents/findings/registry.jsonl) and Step 4.6 (copy pseudocode fixes verbatim into plan issues so workers do not reimplement them from scratch).

When Step 4.5 writes reusable findings, include dedup_key and refresh compiled findings with finding-compiler.sh when that hook exists.

The generated report must preserve this exact heading because downstream validators and ledger readers extract verdicts with a regex anchored to it:

Council Verdict: PASS / WARN / FAIL

Step 5: Record Ratchet Progress

ao ratchet record pre-mortem 2>/dev/null || true

Step 6: Report to User

Tell the user:

1. Council verdict (PASS/WARN/FAIL)
2. Key concerns (if any)
3. Recommendation
4. Location of pre-mortem report

---

Integration with Workflow

/plan epic-123
    │
    ▼
/pre-mortem                    ← You are here
    │
    ├── PASS → /implement
    ├── WARN → Review, then /implement or fix
    └── FAIL → Fix plan, re-run /pre-mortem

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Examples & Troubleshooting

See references/examples.md for worked examples (default inline, --mixed cross-vendor, auto-find recent, --deep high-stakes) and the troubleshooting table (timeouts, FAIL on valid plans, missing product perspectives, gate-blocking, spec-completeness warnings, mandatory-for-epics enforcement).

Troubleshooting

See references/examples.md for the troubleshooting table.

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See Also

• skills/council/SKILL.md — Multi-model validation council
• pre-land-refuters — same adversarial stance aimed at the finished diff: this skill attacks the plan pre-work; that one attacks the completion claim pre-push
• skills/plan/SKILL.md — Create implementation plans
• skills/validate/SKILL.md — Validate code after implementation

Reference Documents

• references/pre-mortem.feature — Executable spec: plan PASS/WARN/FAIL verdict before work, wave-validity gates parallelism, --quick inline default (soc-qk4b)

• references/compiled-prevention.md

• references/scope-mode.md

• references/mandatory-checks.md

• references/scope-predicate-positive-negative-cases.md

• references/write-pre-mortem-output.md

• references/examples.md

• references/council-fail-patterns.md

• references/enhancement-patterns.md

• references/error-rescue-map-template.md

• references/failure-taxonomy.md

• references/simulation-prompts.md

• references/prediction-tracking.md

• references/spec-verification-checklist.md

• references/temporal-interrogation.md

• Shared stale-scope validation rule — re-validate inherited scope estimates against HEAD before acting on deferred beads or handoff docs.