Codex First

Codex First

Claude Code sessions only. Rationale: GPT-5.6 lanes run flat-rate on the ChatGPT plan and top the coding index; Fable's edge is judgment, specs, orchestration, review. Codex types, Claude thinks and verifies. (Adapted from steipete/agent-scripts for James's rig.)

Route

Delegate to Codex (default for hands-on volume):

• implementation from a frozen spec; refactors; mechanical migrations/sweeps
• bug fixes with a known repro; test writing; coverage fills
• CI fixes, dependency bumps, scripts/tooling
• bulk exploration where raw reading ≫ the answer

Keep in Claude (never delegate):

• design, architecture, naming, product judgment — tasks where writing the spec IS the work
• tiny edits (<~20 lines, single obvious change) — delegation overhead loses
• anything needing session tools: MCP, browser, PostHog, memory
• prod operations, always: prod DB (psql), Railway env/deploys, Stripe, DNS, customer emails, anything reading .env/secrets. Codex never touches prod credentials or runs with them in reach.
• destructive/irreversible ops, releases, pushes, merges — Claude-side per repo protocol
• review of Codex output — never delegated, never skipped

Heuristic: prompt reads as a work order → delegate; writing it forces decisions → design, keep it. Mixed task: Claude designs, freezes spec, delegates build-out.

Model/effort routing (updated Aug 26 — James's strategic-loop topology)

• IMPLEMENTATION lanes: gpt-5.6-terra, effort ultra — big, BOLD, atomic work orders (whole migrations, whole screens, whole adapters). Clear frozen spec in, commits out. Claude reviews at the seams, not over the shoulder.
• REVIEWER / THINKING PARTNER: gpt-5.6-sol, effort high→max→ultra — adversarial passes, certification reads, design attacks, strategy pressure-tests. Sol is no longer escalation-only; it is the standing second brain in loops (build: terra → attack: sol → synthesize: Claude).
• Routine/cheap orders: gpt-5.6-luna, effort high. When the 5.6 weekly limit is out, gpt-5.3-codex-spark runs on a SEPARATE quota — use it for routine/mechanical lanes only; judgment and class-1 review stay on Claude seats.
• Opus 5 subagents (via Claude's Agent tool): completeness reads, design rulings, funnel/product craft — the divergent-thinking seat in loops.
• NAMED SEATS (Sep 1, ~/.claude/agents/, load at session start): designer (Opus xhigh, gating design verdict), completeness-reader (Opus xhigh, scope/journey/doc-truth + overengineering strip list, before any merge or "live" claim), explorer (Sonnet low, read-only sweeps — file dumps never enter Fable's context), verifier (Sonnet xhigh, browser/MCP/walkthrough films with evidence, never verdicts). Fable keeps: WO authoring, prod ops, merges, final gate. Hands-on reading in the Fable seat is the priciest seat doing the cheapest work — delegate it. Skip Haiku (200K, a generation back).
• Escalate effort on failure; choose SEAT by role (terra builds, sol attacks, opus designs, Claude gates + synthesizes + ships).
• Every lane must COMMIT its work (atomic commits per tripwire/feature); Claude verifies commits exist + runs the repo's own proof set before any merge (for TS repos typically: lint, typecheck, unit tests, build, plus any disposable-infra verifier the repo carries).

Invoke

Prompt via temp file in the scratchpad, never inline quoting:

bashCopy code
P=$(mktemp "$SCRATCHPAD/codex-XXXXXX"); cat >"$P" <<'EOF'
<goal · repo + key paths · constraints ("don't touch X") · non-goals ·
 proof expected (exact test command) · output shape ("report files changed + test output")>
EOF
codex exec --yolo -C <repo> \
  -c model="gpt-5.6-terra" -c model_reasoning_effort="ultra" \
  -o "$SCRATCHPAD/codex-last.md" - <"$P" 2>/dev/null

• run long jobs with Bash run_in_background; read the -o file on completion
• --yolo only when the working dir is a repo without prod secrets in reach; otherwise default sandbox and review the command requests
• follow-ups: codex exec resume --last from the repo dir (cheaper, keeps context)
• parallel independent orders OK: separate worktrees/dirs, separate -o files
• PRUNE worktrees after each lane lands: rm -rf /private/tmp/<repo>-* + git worktree prune (Jul 30 incident: 219 accumulated worktrees filled the disk to 0 bytes mid-review)
• alternatively spawn the codex:codex-rescue subagent (plugin) for shared-runtime jobs

Prompt contract

Codex starts with ZERO session context. Every prompt: goal, exact repo/paths, constraints, non-goals, proof expected, output shape. Spec quality decides success.

Verify (Claude, always)

• git status -sb + read the FULL diff; judge like a hostile contributor-PR review
• run the focused tests yourself or demand proof output; Codex claims are advisory
• iterate via resume; after 2 failed rounds, take over and do it directly
• ship through normal repo protocol (commit/create-pr skills, CI watch) — Claude's hands on the merge button, never Codex's
• substantive results feed [[adversarial-review]] before merge