codex-implementation

Codex Implementation

Use Codex as a separate implementation agent for bounded code changes. Claude remains responsible for scoping the task, reviewing the diff, running or checking verification, and explaining the final result.

Use this when the user asks for Codex or delegation, or when a bounded task would benefit from a parallel implementation agent producing a patch. Do not let Codex commit, push, deploy, or edit global config unless the user explicitly asked for that.

Workflows

1. Pin the current state with git status --short and note any user changes already present.
2. Define the implementation scope: files or behavior to change, files to avoid, constraints, and verification commands.
3. Create a temporary artifact directory for Codex's report.
4. Run codex exec with repo write access.
5. After Codex exits, inspect git status and git diff.
6. Run the cheapest reliable verification yourself when practical.
7. Report what Codex changed, what Claude verified, and any remaining risks.

Use this command shape:

ARTIFACT_DIR="$(mktemp -d "${TMPDIR:-/tmp}/codex-implementation.XXXXXX")"
REPORT="$ARTIFACT_DIR/report.md"
PROMPT="$ARTIFACT_DIR/prompt.md"

# Write a self-contained prompt to $PROMPT, then run:
codex exec \
    -m gpt-5.6-sol \
    -c 'model_reasoning_effort="medium"' \
    -C "$PWD" \
    --add-dir "$ARTIFACT_DIR" \
    -s workspace-write \
    -o "$REPORT" \
    "$(cat "$PROMPT")"

Prompt Requirements

Tell Codex:

• The exact implementation goal and acceptance criteria.
• The repo path and current branch context if relevant.
• Which existing patterns, files, or tests to inspect first.
• Files or behavior that must not be changed.
• That it must preserve unrelated user changes.
• That it must not commit, push, deploy, or edit global config.
• Which verification commands to run, or to explain why they were skipped.
• To write a concise final report with files changed, verification, and unresolved questions.