host-contract-verification

host-contract-verification is a skill for Claude Code, Codex from devcodex-labs/devcodex. It costs 45 tokens per session (3,553 once invoked), scanned A, original, AGPL-3.0.

A verification procedure for the rules between a host system and its hooks, command-line tools, startup scripts, workspace checks, visible responses, and fallback connections to MCP servers.

In plain words
What is it for?
It is for testing host integrations, replaying recorded cases, synchronizing deployments, and collecting evidence that the contract works.
Why use it?
It helps reveal when an integration works in one path but fails during direct replay, fixture replay, deployment, or fallback use.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing.

Good fit It is for testing host integrations, replaying recorded cases, synchronizing deployments, and collecting evidence that the contract works.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/devcodex-labs/devcodex/host-contract-verification
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 devcodex-labs/devcodex --skill host-contract-verification
Clone the repo
git clone --depth 1 https://github.com/devcodex-labs/devcodex

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 host-contract-verification

README.md
[![agentmods](https://agentmods.dev/badge/skills/devcodex-labs/devcodex/host-contract-verification/github.svg)](https://agentmods.dev/skills/devcodex-labs/devcodex/host-contract-verification)
Your own site
<a href="https://agentmods.dev/skills/devcodex-labs/devcodex/host-contract-verification"><img src="https://agentmods.dev/badge/skills/devcodex-labs/devcodex/host-contract-verification/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 host-contract-verification

Your own site · 80×15
<a href="https://agentmods.dev/skills/devcodex-labs/devcodex/host-contract-verification"><img src="https://agentmods.dev/badge/skills/devcodex-labs/devcodex/host-contract-verification.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,553 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 unknown 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 $0.00045 $0.03553
Opus 5.5 $0.00018 $0.01421
Sonnet 5.5 $0.00009 $0.00711
Haiku 4.5 $0.00005 $0.00355

Measured 1mo ago against content hash d54d49e1c7c7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

host-contract-verification 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.

content/skills/host-contract-verification/SKILL.md · 145 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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. 1mo ago First seen · 145 lines · 45 tokens per session scan A d54d49e1c7c7

Subscribe to this mod's changes

host-contract-verification is a skill published in the GitHub repository devcodex-labs/devcodex (438 stars, last pushed 6d ago), licensed AGPL-3.0. It adds 45 tokens to every session and 3,553 once invoked, about $0.0002 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 2026-08-30.

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