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Codex Master Instructions · majiayu000 | DecimalAI

agent toolingby majiayu000

Codex Master Instructions

majiayu000/codex-master-instructions

Source majiayu000/claude-skill-registry ↗License MIT

Master behavior rules for Codex. Use as the top-priority baseline for request classification, coding quality, dependency awareness, and completion checks across all coding workflows.

NewMaintained

Automatic

Coding pack

Last verified 8/19/2026

What it changes

Passed 6 of 11 test cases with the skill, and 6 of 11 without it.

Without skill50%

With skill50%

Checks it passed that the model alone missed

Checks for `.codex/context/genome.md` before initiating code edits.
Enforces the design gate requirement despite assertions that the project is simple.

2 fixed4 passed either way15 still failing1 broke

Pass-rate lift: 0 pp
Tokens: +113%
Agent turns: 0%
Response time: -35%

Model gemini-3.6-flashMeasured 8/19/2026v16 of 22 cases passed with skill · 11 comparable

Tokens, turns and time describe resource use, not a dollar price.

Use this skill

Save it into your project's skills folder. Claude Code picks it up in its next session.

curl -fsSL --create-dirs -o .claude/skills/majiayu000-codex-master-instructions/SKILL.md https://app.decimal.ai/s/majiayu000-codex-master-instructions/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add majiayu000-codex-master-instructions, and start Claude Code with claude --plugin-dir "$(git rev-parse --show-toplevel)/.agents"

1 · One-time — install the CLI (docs ↗)

pip install "decimalai>=0.15"

2 · Get the skill — writes .agents/skills/majiayu000-codex-master-instructions/ and pins it in .decimal/skills.lock

decimalai skills add majiayu000-codex-master-instructions

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/majiayu000-codex-master-instructions/SKILL.md https://app.decimal.ai/s/majiayu000-codex-master-instructions/SKILL.md

Raw file: /s/majiayu000-codex-master-instructions/SKILL.md ↗ · machine-readable summary at /s/majiayu000-codex-master-instructions.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

See it in action

One of 2 test cases the skill fixed. Same model, same prompt, with and without the skill.

1 of 2

Prompt

I need to add a feature to our 60-file repository. What is your first step before editing code?

What was checked, without and with the skill
Checked	Without skill	With skill
Checks for `.codex/context/genome.md` before initiating code edits.	Missed	Passed

case-10 · gemini-3.6-flash · 8/19/2026 · answers are capped and redacted

What's inside

The instructions your model reads when the skill loads.

SKILL.md228 linessingle file

TL;DR

P0 rules: classify request type -> apply engineering rules -> check dependencies before edit -> run quality gate before completion -> reply in user's language. Scripts: run --help first, treat as black-box.

Codex Master Instructions

Priority: P0. These rules override lower-priority skill instructions.

Activation

Always active as the baseline instruction layer for every turn.
Apply this skill before any lower-priority skill guidance.
Stack task-specific skills on top of this baseline, not instead of it.

Rule Priority

P0: codex-master-instructions
P1: codex-domain-specialist references
P2: other skill instructions

If rules conflict, follow the higher-priority rule.

Short Aliases

Workflow-rich aliases such as $plan, $debug, $create, $review, $deploy, and $handoff live in the Workflow Aliases table below.

Alias	Full Command	Skill
`$gate`	`$codex-execution-quality-gate`	codex-execution-quality-gate
`$intent`	`$codex-intent-context-analyzer`	codex-intent-context-analyzer
`$route`	`$codex-workflow-autopilot`	codex-workflow-autopilot
`$memory`	`$codex-project-memory`	codex-project-memory
`$rigor`	`$codex-reasoning-rigor`	codex-reasoning-rigor
`$design`	`$codex-design-system`	codex-design-system
`$genome`	`$codex-genome`	codex-project-memory
`$doctor`	`$codex-doctor`	codex-execution-quality-gate
`$check`	`auto_gate.py --mode quick`	codex-execution-quality-gate
`$check-full`	`auto_gate.py --mode full`	codex-execution-quality-gate
`$check-deploy`	`auto_gate.py --mode deploy`	codex-execution-quality-gate
`$install-hooks`	`install_hooks.py`	codex-execution-quality-gate
`$install-ci`	`install_ci_gate.py`	codex-execution-quality-gate

Track record

Benchmark

6 / 11

test cases passed, vs 6 / 11 without

Adoption

Users: 0
Times used: 0

Safety and source details

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v4 — 8/3/2026

View 15 scanner checks

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review

Source

Imported

majiayu000 / claude-skill-registry

skills/agent/codex-master-instructions/SKILL.md

View on GitHub ↗

License MITImported 8/3/2026Version v1

More skills from the same source and nearby in the registry, with their headline benchmark lift.

Ready to supercharge your AI agents?

See it in action

What's inside

TL;DR

Codex Master Instructions

Activation

Rule Priority

Short Aliases

Track record

Benchmark

Adoption

SkillSafety

Source

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