# Fable Super God Mode > Use when deterministic/backend/algorithmic work needs an independent correctness check — numeric, boundary, parsing, state-machine, concurrency, or scoring/data math and API contracts; when critiquing a plan before multi-step deterministic execution; when reviewing a diff before committing; when you want a debugging second opinion after a failed fix attempt; or when the user mentions Codex, GPT-5… - **Type:** Skill - **Install:** `agentstack add skill-nagarjuna-msr-fable-god-mode-fable-super-god-mode` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [nagarjuna-msr](https://agentstack.voostack.com/s/nagarjuna-msr) - **Installs:** 0 - **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [nagarjuna-msr](https://github.com/nagarjuna-msr) - **Source:** https://github.com/nagarjuna-msr/fable-god-mode/tree/main/skills/fable-super-god-mode ## Install ```sh agentstack add skill-nagarjuna-msr-fable-god-mode-fable-super-god-mode ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # Fable Super God Mode ## What this adds This skill adds ONE thing to Fable God Mode: a GPT-5.5 lane, reached through a vendored one-shot bridge to the Codex CLI. GPT-5.5 acts as Fable's deterministic specialist and independent critic on correctness-heavy work. Fable God Mode's 10-80-10 discipline still governs everything — Fable 5 plans, cheaper Claude subagents execute, Fable reviews and owns final quality. Nothing here replaces or relaxes that loop; see `skills/fable-god-mode/SKILL.md` (installed as the `fable-god-mode` skill). This skill only inserts a second, independent model at specific correctness checkpoints inside that same loop. ## When to use the GPT-5.5 lane Keep it gated. Fire the lane for: - **Deterministic / backend / algorithmic work** — numeric, boundary, parsing, state-machine, concurrency, data/scoring math, or API-contract correctness. - **Plan critique** — before executing a multi-step deterministic plan. - **Diff review** — of substantial deterministic changes before finalizing or committing. - **Debugging second opinion** — AFTER one failed fix attempt, not before. Do NOT fire it for creative work, frontend / visual / UX, copy / prose / docs, conversational turns, or trivial edits — a second model there adds cost without decisive signal. Full routing detail lives in `references/routing.md`. ## Running a critique Three steps: write a prompt file, invoke the bridge, read the envelope. 1. **Write the prompt file.** A plain text/markdown file containing the FULL, self-contained critique request: the task context plus the material to review inline, or paths for Codex to read. The bridge sends only this file (plus a fixed output-contract suffix) — never your environment. Codex runs read-only-sandboxed and may READ files in the working directory only if the prompt points it at paths. 2. **Invoke the bridge** (Node ≥18, zero dependencies): ```sh node "${CLAUDE_SKILL_DIR}/scripts/ask-codex.mjs" [--model ] [--timeout ] ``` Model selection: `--model` flag > `CODEX_MODEL` env var > default `gpt-5.5` (always passed explicitly to the CLI). The CLI is run as `codex exec --sandbox read-only --ephemeral`, non-interactive. 3. **Read the envelope.** The bridge prints ONE JSON object on stdout: ```json {"verdict", "model", "summary", "findings": [...], "error", "elapsed_ms"} ``` `verdict` is one of `approved` | `findings` | `codex_unavailable`. Each findings item is `{severity, category, where, issue, suggestion}` where `severity` ∈ `critical | high | medium | low`. Exit codes: `0` = approved, `10` = findings, `20` = codex_unavailable, `2` = usage error (bad arguments — a caller bug you must fix, not an outage). ## Handling the verdict Three states, and you must treat them differently. - **`approved`** — GPT-5.5 found nothing. This ADDS to your own review; it does not replace it. Ship on the union of both. - **`findings`** — adjudicate below. - **`codex_unavailable`** — this is the single most important rule. **Tri-state rule.** `codex_unavailable` means NO review happened. You MUST surface this plainly to the user — "GPT-5.5 review did not run: ``" — and proceed on your own findings only. An outage must NEVER be reported as a clean review, and must NEVER be silently ignored. This is a deliberate improvement over fail-open designs that print "approve" on error. **Union rule.** GPT-5.5 findings ADD to your own self-review findings. GPT's approval or silence NEVER drops a finding you already had. Adjudicate each GPT finding on merit: accept the real ones and act on them; reject false positives with a stated reason. The result you ship is your findings ∪ the accepted GPT findings. **Log every critique** as one JSON line appended to the project's `.orchestration/feedback.jsonl`: ```json {"ts": "", "artifact": "", "reviewer": "gpt-5.5", "verdict": "", "findings": , "accepted": , "rejected": , "notes": ""} ``` ## Data disclosure Using this lane sends the prompt file's contents — and any files Codex reads under it — to OpenAI. The user consented to this at install. Do not send secrets, credentials, or files the user has not approved for disclosure. ## Setup Any paid ChatGPT plan (Plus and up) includes the Codex CLI; the free tier has limited quota. The full install / login / verification procedure lives in `references/setup-codex.md` — defer to it. Advanced path: AgentBridge (github.com/quilin-ai/agent-bridge, MIT) enables live bidirectional Fable↔Codex sessions; see `references/routing.md` for when that is worth it. It is NOT installed or configured by this skill's installer. ## References Load these on demand: - `references/routing.md` — full routing detail: which lane fires when, the NOT-for list, and the AgentBridge advanced path. - `references/setup-codex.md` — Codex CLI install, login, and verification. - `references/verdict-schema.json` — the JSON Schema enforced on GPT-5.5's raw verdict (`approved`/`findings` only; `codex_unavailable` is the bridge's own state, added in the envelope along with `model`, `error`, and `elapsed_ms`). ## Source & license This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [nagarjuna-msr](https://github.com/nagarjuna-msr) - **Source:** [nagarjuna-msr/fable-god-mode](https://github.com/nagarjuna-msr/fable-god-mode) - **License:** MIT Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/skill-nagarjuna-msr-fable-god-mode-fable-super-god-mode - Seller: https://agentstack.voostack.com/s/nagarjuna-msr - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.