fable-validate-loop

name	fable-validate-loop
description	Use when the user asks to validate a GitHub issue with Fable 5 and then autonomously drive it to a reviewed PR in one shot — "fable-validate-loop", "fable validate and work on

fable-validate-loop

Chain fable-validate → (conditional) update issue → fableplan → work-on-issue-loop into one autonomous run: Fable 5 validates the issue, the main agent fixes the issue description if needed, Fable 5 plans the implementation (plan posted to the issue), and work-on-issue-loop implements the plan and drives the PR through review to convergence. This is fable-validate's interactive handoff made unattended — the loop reads its own verdicts and proceeds, instead of waiting for the user to reply.

Do not skip or reorder the chain. Validation gates planning (a plan built on refuted claims is wrong), and the plan gates implementation (that's the point of routing through fableplan). The only sanctioned skip is the step-4 Capability gate (Capability < 2 / score < 50 bypasses fableplan). Every other step of each skill still runs; only the "wait for the user's reply" moments are replaced by the decision rules below.

Input

Same defaults as fable-validate: issue URL, #<N> / <N> / owner/repo#N, or nothing (defaults to the latest open issue in the current repo).

Steps

1. Run fable-validate

Invoke the fable-validate skill for the target issue (Skill tool, skill: fable-validate). Let it run fully — Fable 5 subagent validation, spot-check, verdict — producing the standard verdict block:

**#<N>: Update issue description? <Yes|No>**  ·  Complexity: <score>/100 — Capability <k> (<driver>); Volume <v> · fableplan: <yes|no>  ·  Scope: <OK | too large — split/umbrella/narrow>

Treat the verdict as structured output to parse yourself, not a prompt to wait on. Record the resolved issue number — every later step targets exactly this issue.

2. Scope gate — stop if the issue is unsafe to auto-implement

Check the verdict's Scope field, Architecture section, and Concerns (for an already-addressing PR) before doing anything else:

Condition	Action
Scope: too large (split / umbrella / narrow flagged)	STOP. Report the disposition and proposed parts. Implementing a multi-part issue as one PR reproduces the scope problem in the diff — splitting is a human call.
Architecture marked ❌ Infeasible	STOP. Report the infeasibility and the "Optimal direction" note; planning and implementing a design the validation rejected would ship the wrong fix.
A merged PR already implements the fix	STOP. Report the PR and the close/repurpose recommendation — nothing left to implement.
An open PR is already addressing the issue	STOP. Report the overlapping PR; supersede/join/wait is a human call.

Otherwise (Scope: OK; architecture ✅/⚠️ or not applicable; no PR already addressing it), continue.

3. Apply the update-issue edits, if called for

If the verdict says Update issue description? Yes, apply the suggested title/body edits now per fable-validate step 5 / validate-issue step 8 — claim-verification gate, final consistency pass, and the stacked attribution line (Validated with LLM: Fable 5 | high | Harness: Claude Code | fable-validate-loop) — from the current checkout (no worktree for issue edits).

If No, skip straight to step 4.

Order matters: the edits land before fableplan runs, so the Fable 5 planner fetches and plans against the corrected issue, not the flawed original.

4. Run fableplan — planning phase only (skip when Capability < 2)

Capability gate: if the verdict's validated complexity score is below 50 (Capability < 2 under the validate-issue band encoding), skip fableplan and go straight to step 5 — work-on-issue-loop plans adequately for low-capability-band changes on its own. Safety carve-out (overrides the gate): if the validation flags money, data integrity, security, or an auto-protective mechanism anywhere in its findings, run fableplan regardless of score. (If the user wants a plan unconditionally, that's fable-validate-fableplan-loop — this same chain with the gate removed.)

Capability-3 note: this gate intentionally runs fableplan for band-3 issues (score ≥ 75) even though their verdict line reads fableplan: no. That signal's no assumes a Fable 5 build (the band table's routing); this loop implements via work-on-issue-loop on the session model, so the posted Fable plan is the only guaranteed Fable 5 involvement for a band-3 issue here — skipping it would drop Fable from the hardest issues entirely.

Otherwise, invoke the fableplan skill for the same issue number (Skill tool, skill: fableplan), and scope it to its planning phase — steps 1 through 5 only: fetch the issue, dispatch the Fable 5 Plan subagent, sanity-check the plan against the code, post the vetted plan as an issue comment, and relay it. Do NOT execute fableplan's steps 7–8 (worktree + build) — implementation belongs to work-on-issue-loop in step 5, which owns the implement → PR → review chain; building here would duplicate it outside that chain.

Give the planning subagent the validation verdict (the scratchpad copy from step 1) alongside the issue — the plan must respect what validation established (verified/refuted claims, the Optimal-direction note when architecture was ⚠️, 5b concerns).

Keep the vetted plan's scratchpad file — step 5 passes it through. If fableplan fails after its internal retry, stop and report; don't fall back to planning yourself or implementing unplanned.

5. Hand off to work-on-issue-loop

Invoke the work-on-issue-loop skill for the same issue number (Skill tool, skill: work-on-issue-loop). Pass the issue number through explicitly — don't let it re-resolve "latest issue" — and instruct it that the implementation must follow the Fable 5 plan: point it at the plan's scratchpad file and the posted issue comment (## Implementation plan (Fable 5)), and tell it deviations from the plan are allowed only when the code contradicts the plan, and must be named in the PR body. (If step 4 was skipped by the Capability gate, there is no plan — hand off the issue alone and note the skip.)

It runs its full loop: work-on-issue implements in a worktree and opens the PR, the loop triggers @claude review, and fix-pr-review cycles until convergence.

6. Report

Relay work-on-issue-loop's final summary (PR URL, review cycles, final verdict), prefixed with one line covering the head of the chain: scope gate passed, issue updated or not, plan posted (comment URL) or skipped by the Capability gate.

Cap the whole report at 55 words, ELI18 — plain language, no jargon, as if explaining the outcome to a smart 18-year-old with no context on this codebase.

Red Flags — STOP

Situation	Action
Tempted to skip validation or planning and jump to implementation	Never reorder — validate-then-plan-then-build is the point of this skill; the only sanctioned skip is the step-4 Capability gate (score < 50 / Capability < 2, no safety flags)
Scope: too large, Architecture ❌ Infeasible, or a PR already addressing the issue	Stop and report per step 2 — the cases the loop can't safely auto-resolve
Tempted to wait for a literal user reply to fable-validate's or fableplan's prompt	Parse the output yourself and proceed per the step rules
Verdict says Update issue description? Yes	Apply the edits before fableplan runs, so the plan targets the corrected issue
fableplan about to enter its build steps (7–8)	Don't — stop it at step 5; work-on-issue-loop owns implementation
fableplan's sanity-check finds the plan structurally wrong	Stop and report — don't hand a broken plan to work-on-issue-loop, and don't silently re-plan