preflight

preflight is a skill for Claude Code, Codex from ogulcancelik/agent-skills. It costs 49 tokens per session (1,347 once invoked), scanned A, original, MIT.

A pre-implementation review process that uses fresh-context specialists to examine a proposed code change for regression risk. It then checks the smallest correct change after implementation.

In plain words
What is it for?
Use it before meaningful code changes when you want a risk challenge, a concise implementation contract, verification, regression review and, where needed, simplification.
Why use it?
It reduces the chance that the implementer overlooks a side effect or becomes fixed on an incorrect diagnosis. The separate review creates a risk checkpoint before and after coding.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it before meaningful code changes when you want a risk challenge, a concise implementation contract, verification, regression review and, where needed, simplification.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ogulcancelik/agent-skills/preflight
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add ogulcancelik/agent-skills --skill preflight
Clone the repo
git clone --depth 1 https://github.com/ogulcancelik/agent-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for preflight

README.md
[![agentmods](https://agentmods.dev/badge/skills/ogulcancelik/agent-skills/preflight/github.svg)](https://agentmods.dev/skills/ogulcancelik/agent-skills/preflight)
Your own site
<a href="https://agentmods.dev/skills/ogulcancelik/agent-skills/preflight"><img src="https://agentmods.dev/badge/skills/ogulcancelik/agent-skills/preflight/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for preflight

Your own site · 80×15
<a href="https://agentmods.dev/skills/ogulcancelik/agent-skills/preflight"><img src="https://agentmods.dev/badge/skills/ogulcancelik/agent-skills/preflight.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,347 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00049 $0.01347
Opus 5 $0.00024 $0.00674
Sonnet 5 $0.00010 $0.00269
Haiku 4.5 $0.00005 $0.00135

Measured 9d ago against content hash 865e671b13d6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

preflight scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/preflight/SKILL.md · 165 lines

How it starts

The opening of the file, as written. The whole thing — 165 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Preflight

Preflight reduces implementation bias. The implementing agent becomes attached to its diagnosis and design. A fresh specialist that sees the problem and code, but not the proposed solution, can find regressions before the design is locked.

The flow is:

investigate → risk challenge → concise contract → approve → implement → verify → simplify → finish

Rules

Use this skill only when the top-level user explicitly requests preflight or a risk gate. Never invoke it from a delegated child. If preflight was not requested, suggest it once and wait.

The main agent owns investigation, scope, implementation, and communication. Children only challenge, verify, review, or simplify. Give each child one job. Reuse it only to recheck its own findings.

Prefix every child assignment with:

You are a bounded preflight child. Do not invoke preflight, delegate work, or spawn agents. Complete only the assigned analysis and return it to the parent.

Always run the pre-implementation risk challenge. For meaningful code changes, also run a contract verifier and regression reviewer after implementation. Run a simplifier when the patch adds meaningful structure. Add an evidence challenger only when the reproduction is uncertain or the change is unusually risky. Do not create agents merely to fill a process.

1. Investigate

Read repository instructions and trace the real execution path before planning. For bugs, prefer a real user-path reproduction, then an existing integration signal, then an owning-layer test. If none is available, label the diagnosis as a hypothesis. For features, define one observable acceptance signal.

Separate facts from assumptions. Investigation cannot expand the request.

2. Run the independent risk challenge

Give a fresh agent the raw request, evidence, repository instructions, relevant code, and existing tests. Do not give it the main agent's diagnosis, implementation plan, architecture, or proposed patch.

Use this prompt:

Find concrete regressions this requested change could cause. For each finding, cite the existing behavior, exact code path, evidence, and causal failure chain. Do not suggest implementation designs, general improvements, defensive hardening, or hypothetical risks without evidence. Report unknowns separately.

Read the full file on GitHub · 165 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 165 lines · 49 tokens per session scan A 865e671b13d6

Subscribe to this mod's changes

preflight is a skill published in the GitHub repository ogulcancelik/agent-skills (76 stars, last pushed 6d ago), licensed MIT. It adds 49 tokens to every session and 1,347 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.