Lisa Codex Parity

Lisa ↔ Codex Parity

Lisa is distributed for both Claude Code and Codex. Claude is the production path; the Codex side is derived/installed separately (see "Where Codex artifacts live" below). When a feature surface changes on the Claude side — or when either harness ships a new capability — the Codex side drifts. This skill is the repeatable protocol for closing that gap by having Claude and Codex converse until they reach parity.

It generalizes the hooks-parity pass that produced [[reference-codex-hooks-capabilities]] — read that and the worked example below before starting.

Core principle: empirical, not documentary

Do not trust documentation or assumptions about what Codex supports. Codex's behavior across versions is subtle and has bitten Lisa before (e.g. plugin- bundled hooks/hooks.json silently never runs; apply_patch passes the patch as a string under tool_input.command, not an array). Every parity claim must be backed by one of:

1. Source-read — Codex inspects its own installed binary/source/config schema (codex --version, codex features list, ~/.codex/, vendored Rust source, generated schemas).
2. Runtime capture — Codex runs a real codex exec session and observes actual behavior (capture hook stdin, confirm a block happened, confirm injected context reached the model).

Tag every finding [VERIFIED], [VERIFIED-BY-RUN], or [UNKNOWN]. Treat [UNKNOWN] as "must run a test before relying on it."

Prerequisites

• The codex CLI is installed and authed on this machine. How to drive it non- interactively (one-shot, resume, flags, /tmp brief→answer pattern) is in [[reference-codex-cli-collaboration]]. Key invocation: codex exec -c mcp_servers={} -c model_reasoning_effort="high" "<prompt>", continue with codex exec resume --last "<prompt>".
• Codex has full filesystem access here, so it can verify claims about Lisa's own files itself and run isolated tests under a throwaway CODEX_HOME.

The protocol

Step 1 — Inventory the Claude side

Pin down exactly what the feature surface is on the Claude side and where it lives in the repo. Source of truth is plugins/src/ (never the generated plugins/lisa* artifacts — see PROJECT_RULES.md). For each item record: the event/trigger, matcher, the script/file, and which stack(s) it applies to.

Step 2 — Brief Codex; have it investigate the Codex side

Write a brief to /tmp/<topic>-brief.md listing the Claude-side items and asking precise questions about the Codex equivalent. Have Codex write its answer to /tmp/<topic>-answer.md. Insist on source-read and runtime capture, with confidence tags. A good question set covers:

• Does Codex support this surface at all? Via what config mechanism and exact schema/shape? (For hooks: ~/.codex/hooks.json / project .codex/hooks.json / config.toml [hooks], gated by [features].codex_hooks = true — NOT a plugin-bundled hooks.json, which does not run.)
• Map each Claude trigger/event/field to its Codex equivalent, or "no equivalent."
• Input/output/exit contract differences (field names, tool names, blocking, context injection shape).
• Codex-only capabilities Claude lacks (e.g. PermissionRequest).
• Porting caveats (env vars not set, cwd, timeouts, matcher semantics).

For load-bearing or [UNKNOWN] claims, send a follow-up brief asking Codex to run a focused test and report the command + observed output.

Step 3 — Build the gap matrix

Classify every Claude-side item into exactly one bucket:

• Has equivalent — works on Codex as-is once installed correctly.
• Needs adaptation — equivalent event exists but the contract differs (e.g. apply_patch gives a patch body, not tool_input.file_path). Implement the adaptation.
• No equivalent — Codex genuinely lacks it. Document it as intentionally not ported; do not fake it.

Step 4 — Implement the missing equivalents

Make the changes under the Codex-side source of truth, then rebuild. See "Where Codex artifacts live." Keep subtle, easy-to-get-wrong logic (envelope parsing, output shapes) in a single shared helper so it can't drift between scripts.

Step 5 — Empirical end-to-end verification by Codex

Do not declare parity from unit tests alone. Have Codex stand up a throwaway project (isolated CODEX_HOME), wire in the actual artifacts, run a real codex exec session that exercises the feature, and confirm the observable outcome (file reformatted, edit blocked + file hash unchanged, context injected, etc.). Capture commands and outputs in /tmp/<topic>-e2e-answer.md.

Step 6 — Land it

• Add/maintain regression tests (shell hooks are testable by spawning them with crafted JSON — see tests/unit/codex/codex-edit-hooks.test.ts).
• bun run typecheck, bun run test:unit, bun run build, and ensure the plugin build is deterministic so bun run check:plugins passes once committed.
• Document the no-equivalent items in code comments and update the relevant capability memory ([[reference-codex-hooks-capabilities]] and siblings) so the next parity pass starts from current knowledge.

Where Codex artifacts live

• Skills load via the .codex-plugin skills pointer (SKILL.md only) — see [[reference-codex-plugin-skill-loading]]. Generated by scripts/generate-codex-plugin-artifacts.mjs during bun run build:plugins.
• Hooks are NOT distributed via the plugin (Codex doesn't execute plugin- bundled hooks). They are installed into the project's .codex/hooks.json by src/codex/hooks-installer.ts (catalog of which scripts ship per stack), with the shell scripts in src/codex/scripts/ and a tagged-merge writer in src/codex/hooks-merger.ts.
• MCP / settings / agents / AGENTS.md have their own installers under src/codex/ (*-installer.ts). Check there before assuming a surface is unported.

Known Codex capability reference (as of codex-cli 0.125.0)

Authoritative details live in [[reference-codex-hooks-capabilities]]. Quick recap:

• Hook events: PreToolUse, PermissionRequest, PostToolUse, SessionStart, UserPromptSubmit, Stop. No SubagentStart, SessionEnd, Notification, PreCompact.
• Context injection: {"hookSpecificOutput":{"hookEventName":"<event>","additionalContext":"..."}} on SessionStart/UserPromptSubmit/PostToolUse (not PreToolUse).
• Blocking: PreToolUse exit 2 + stderr, or permissionDecision:"deny".
• Edit tool is apply_patch; patch body is the string tool_input.command (parse *** Add/Update/Delete File: headers); no tool_input.file_path.
• CLAUDE_PLUGIN_ROOT/CODEX_PLUGIN_ROOT are not set for hook commands.

Re-verify these against the installed Codex version at the start of each pass — new Codex releases may add events or change contracts.

Worked example — the hooks parity pass

The canonical reference run: inventoried Lisa's bundled hooks, drove Codex to map them to Codex events (source-read), captured the real apply_patch hook envelope by running Codex, found the post-edit hooks silently skipped Codex's primary edit path and the migration guard's command[1] parse was a no-op, implemented a shared _extract-edit-paths.sh, and had Codex prove end-to-end that format-on-edit reformats an apply_patch file and block-migration denies an apply_patch migration edit. See src/codex/scripts/ and tests/unit/codex/codex-edit-hooks.test.ts.

Definition of done

• Every Claude-side item is classified (has-equivalent / adapted / no-equivalent) with at least one empirical verification backing the "works" claims.
• Implemented equivalents pass unit tests AND a real Codex codex exec run.
• No-equivalent items are documented in code + capability memory.
• typecheck, test:unit, build, and check:plugins are green.