hydraflow: Skill for Codex

.codex/skills/hf.diff-sanity/SKILL.md

hf.diff-sanity is a skill for Codex from T-rav/hydraflow. It costs 26 tokens per session (443 once invoked), scanned A, original, Apache-2.0.

A read-only review of the current Git changes for accidental deletions, debug code, missing imports, scope creep, secrets, malformed strings, and obvious logic errors.

In plain words
What is it for?
Use it after making changes and before committing to receive file, line, and problem descriptions.
Why use it?
It provides a focused pre-commit sanity check for mistakes that can be easy to miss in a large diff.

Skill for Codex

Written for Codex: installed under .codex/.

This is T-rav/hydraflow's own configuration. It tells Codex how to work on hydraflow itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything hydraflow configures →

Reuse

Borrowing it

Nothing to install: this file belongs to T-rav/hydraflow. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/T-rav/hydraflow/staging/.codex/skills/hf.diff-sanity/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/T-rav/hydraflow

Made for: 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.

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README.md
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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.

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Your own site · 80×15
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Per session 26 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 443 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.
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 $0.00026 $0.00443
Opus 5.5 $0.00010 $0.00177
Sonnet 5.5 $0.00005 $0.00089
Haiku 4.5 $0.00003 $0.00044

Measured 1mo ago against content hash c9c513957672, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

hf.diff-sanity 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 1mo 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.

.codex/skills/hf.diff-sanity/SKILL.md · 57 lines

What it actually says

Diff Sanity Check

Review the current branch diff for common implementation mistakes before committing. This is a read-only check — it does not modify files.

When to Use

  • After implementing changes, before committing
  • As a pre-review sanity pass
  • When you want a quick check for accidental mistakes

Instructions

  1. Get the diff of changes on the current branch:

    git diff origin/main...HEAD
    

    If that's empty, fall back to git diff (unstaged) or git diff --cached (staged).

  2. Review the diff for these problems:

    • Accidental deletions — unrelated code removed that should not have been
    • Leftover debug code — print(), console.log(), debugger, breakpoint(), commented-out code
    • Missing imports — new symbols referenced but not imported; removed code with stale imports
    • Scope creep — files changed that are unrelated to the issue
    • Hardcoded secrets or credentials — API keys, tokens, passwords in the diff
    • Broken string literals — unclosed quotes, malformed f-strings
    • Obvious logic errors — inverted conditions, off-by-one, unreachable code after return
  3. For each problem found, note the file path, line, and description.

  4. Produce structured output:

If all checks pass:

DIFF_SANITY_RESULT: OK
SUMMARY: No issues found

If problems are found:

DIFF_SANITY_RESULT: RETRY
SUMMARY: <comma-separated list of problem categories found>
FINDINGS:
- <file:line — description>

Important

  • Do NOT modify any files. This is a read-only review.
  • Focus on objective mistakes, not style preferences.
  • If the diff is too large (>15,000 chars), summarize by file and focus on the riskiest changes.
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. 1mo ago First seen · 57 lines · 26 tokens per session scan A c9c513957672

Subscribe to this mod's changes

hf.diff-sanity is a skill published in the GitHub repository T-rav/hydraflow (5 stars, last pushed 2d ago), licensed Apache-2.0. It adds 26 tokens to every session and 443 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-08-31.

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