Agent skill

oracle-codex

This skill should be used when the user asks to "use Codex", "ask Codex", "consult Codex", "use GPT for planning", "ask GPT to review", "get GPT's opinion", "what does GPT think", "second opinion on code", "consult the oracle", "ask the oracle", or mentions using an AI oracle for planning or code review. NOT for implementation tasks.

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Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/oracle-codex

SKILL.md

Codex Oracle

Use OpenAI Codex CLI as a read-only oracle — planning, review, and analysis only. Codex provides its perspective; you synthesize and present results to the user.

Sandbox is always read-only. Codex must never implement changes.

Arguments

Parse $ARGUMENTS for:

  • query — the main question or task (everything not a flag). Required — if empty, tell the user to provide a query and stop.
  • --reasoning <level> — override reasoning effort (low, medium, high, xhigh). Optional; default is auto-selected based on complexity.

Prerequisites

Run the check script before any Codex invocation:

bash
scripts/check-codex.sh

If it exits non-zero, display the error and stop. Use the wrapper for all codex exec calls:

bash
scripts/run-codex-exec.sh

Configuration

Setting Default Override
Model gpt-5.3-codex Allowlist only (see references/codex-flags.md)
Reasoning Auto --reasoning <level> or user prose
Sandbox read-only Not overridable

Reasoning Effort

Complexity Effort Timeout Criteria
Simple low 300000ms <3 files, quick question
Moderate medium 300000ms 3–10 files, focused analysis
Complex high 600000ms Multi-module, architectural thinking
Maximum xhigh 600000ms Full codebase, critical decisions

For xhigh tasks that may exceed 10 minutes, use run_in_background: true on the Bash tool and set CODEX_OUTPUT so you can read the output later.

See references/codex-flags.md for full flag documentation.

Workflow

1. Parse and Validate

  1. Parse $ARGUMENTS for query and --reasoning
  2. Run scripts/check-codex.sh — abort on failure
  3. Assess complexity to select reasoning effort (unless overridden)

2. Construct Prompt

Build a focused prompt from the user's query and any relevant context (diffs, file contents, prior conversation). Keep it direct — state what you want Codex to analyze and what kind of output you need. Do not implement; request analysis and recommendations only.

3. Execute

Invoke via the wrapper with HEREDOC. Set the Bash tool timeout per the reasoning effort table above.

bash
EFFORT="<effort>" \
CODEX_OUTPUT="/tmp/codex-${RANDOM}${RANDOM}.txt" \
scripts/run-codex-exec.sh <<'EOF'
[constructed prompt]
EOF

For xhigh, consider run_in_background: true on the Bash tool call, then read CODEX_OUTPUT when done.

4. Present Results

Read the output file and present with attribution:

## Codex Analysis

[Codex output — summarize if >200 lines]

---
Model: gpt-5.3-codex | Reasoning: [effort level]

Synthesize key insights and actionable items for the user.

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