ccode-to-codex: Skill for Codex

.codex/skills/verify-skill-migration/SKILL.md

verify-skill-migration is a skill for Codex from zuharz/ccode-to-codex. It costs 17 tokens per session (968 once invoked), scanned B, original, MIT.

A validator for checking migrated Codex skills and related documentation for structural, naming, reference, and compatibility problems.

In plain words
What is it for?
Use it after migration batches to check front matter, file structure, references, cross-references, old skill syntax, and outdated paths.
Why use it?
It catches common migration errors before a migrated skill set is finalized.

Skill for Codex

Written for Codex: installed under .codex/. Also seen: mentions AGENTS.md; mentions Codex.

This is zuharz/ccode-to-codex's own configuration. It tells Codex how to work on ccode-to-codex 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 ccode-to-codex configures →

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is python3 tools/migration_support/validate_names.py.

Reuse

Borrowing it

Nothing to install: this file belongs to zuharz/ccode-to-codex. 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/zuharz/ccode-to-codex/main/.codex/skills/verify-skill-migration/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/zuharz/ccode-to-codex

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.

agentmods badge for verify-skill-migration

README.md
[![agentmods](https://agentmods.dev/badge/skills/zuharz/ccode-to-codex/verify-skill-migration.svg)](https://agentmods.dev/skills/zuharz/ccode-to-codex/verify-skill-migration)
Your own site
<a href="https://agentmods.dev/skills/zuharz/ccode-to-codex/verify-skill-migration"><img src="https://agentmods.dev/badge/skills/zuharz/ccode-to-codex/verify-skill-migration.svg" alt="Measured on agentmods" height="20"></a>
Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 968 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Agent Snooping · line 110
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
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 $0.00017 $0.00968
Opus 5 $0.00009 $0.00484
Sonnet 5 $0.00003 $0.00194
Haiku 4.5 $0.00002 $0.00097

Measured 8d ago against content hash 8489805bdca7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade B, and why

verify-skill-migration scanned grade B with 1 finding 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 8d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/validate_skill_migration.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Enumerates other installed skillsmediumAgent snooping

Other skills' SKILL.md files reveal prompts, capabilities and secrets that should be invisible to peers.

--scan-dir .codex/skills/verify-skill-migration
.codex/skills/verify-skill-migration/SKILL.md · 143 lines

How it starts

The opening of the file, as written. The whole thing — 143 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Verify Skill Migration

Use the canonical migration validator after each batch and before finalizing a migrated skill set.

The validator implementation lives at:

  • .codex/skills/verify-skill-migration/scripts/validate_skill_migration.py

Use the stable repo entrypoint for normal runs:

python3 tools/migration_support/validate_names.py

Checks

structural-integrity

  • Fails on MCP callable namespaces that still preserve hyphenated server IDs

frontmatter

  • Applies to SKILL.md entrypoints only
  • Parses YAML frontmatter
  • Requires name and description
  • Fails on prohibited keys: allowed-tools, effort, metadata

line-count

  • Warns when a SKILL.md file reaches 500+ lines
  • Warning only, not a failure

references

  • Validates references/ directories under the scan scope
  • Fails on empty references/ directories
  • Fails on empty reference files, including nested files

Cross-References Check

  • Warns on unknown skill references
  • Uses discovered skill names instead of treating arbitrary backticked words as skills

skill-remnants

  • Fails on legacy skill primitive call syntax in Codex artifacts

stale-paths

  • Fails on operational legacy migration path references
  • Ignores provenance banner lines such as Source: and Generated by:

operator-guidance

  • Applies to the migration-family skill packages
  • Fails on operator-facing repo paths that do not resolve there
  • Fails on mistaken filesystem-root repo paths such as /.codex/...
  • Fails on legacy slash-skill invocations in migration-family operational guidance
  • Resolves skill-local references/... and scripts/... before repo-root paths

agent-dependencies

  • Fails on unresolved named agent runtime dependencies
  • Treats only .codex/agents/*.toml as authoritative runtime contracts
  • Does not let legacy .codex/agents/*.md references satisfy dependency resolution

Read the full file on GitHub · 143 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 8d ago First seen · 143 lines · 17 tokens per session scan B 8489805bdca7

Subscribe to this mod's changes

verify-skill-migration is a skill published in the GitHub repository zuharz/ccode-to-codex (70 stars, last pushed 18d ago), licensed MIT. It adds 17 tokens to every session and 968 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it B with 1 finding (enumerates other installed skills). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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