feature-verify

feature-verify is a skill for Claude Code, Codex from sd0xdev/sd0x-harness. It costs 75 tokens per session (3,198 once invoked), scanned A, original, MIT.

A read-only guide for checking whether a deployed software feature works through its API, logs, and other observations.

In plain words
What is it for?
Use it for post-deployment smoke tests, API checks, runtime investigations, and integrated verification.
Why use it?
It helps diagnose production problems and verify behavior without changing data or system state.

Skill for Claude CodeCodex

Part of the sd0x-dev-flow plugin — 40 skills, 16 agents, 5 hooks shipped together

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.

agentmods
npx agentmods add skills/sd0xdev/sd0x-harness/feature-verify
Any agent
npx skills add sd0xdev/sd0x-harness --skill feature-verify
Clone the repo
git clone --depth 1 https://github.com/sd0xdev/sd0x-harness

Made for: Claude Code, Codex.

Or install sd0x-dev-flow, the plugin that ships this one along with the rest of its 40 skills, 16 agents, 5 hooks.

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 feature-verify

README.md
[![agentmods](https://agentmods.dev/badge/skills/sd0xdev/sd0x-harness/feature-verify.svg)](https://agentmods.dev/skills/sd0xdev/sd0x-harness/feature-verify)
Your own site
<a href="https://agentmods.dev/skills/sd0xdev/sd0x-harness/feature-verify"><img src="https://agentmods.dev/badge/skills/sd0xdev/sd0x-harness/feature-verify.svg" alt="Measured on agentmods" height="20"></a>
Per session 75 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,198 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
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 $0.00075 $0.03198
Opus 5 $0.00037 $0.01599
Sonnet 5 $0.00015 $0.00640
Haiku 4.5 $0.00007 $0.00320

Measured 4d ago against content hash 21d6be8696f7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

feature-verify scanned grade A 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 4d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

> **Tool safety note**: `allowed-tools` includes `Bash` for curl/log queries. Read-only enforcement is behavioral — all commands MUST be reviewed against `references/safety-rules.md` before execution. Codex independently
skills/feature-verify/SKILL.md · 289 lines

How it starts

The opening of the file, as written. The whole thing — 289 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Feature Verify — Runtime-First API Verification

Trigger

  • Keywords: verify, investigate, diagnose, check if working, post-deploy, smoke test, validate
  • User wants to confirm deployed feature behavior
  • User provides environment access (API URL, log system, credentials)

When NOT to Use

Need Use Instead
Modify data or state /feature-dev
Code quality review /codex-review-fast
Generate unit tests /codex-test-gen
Security audit /codex-security
Run local tests /verify
Review test coverage /codex-test-review

Core Principle

⚠️ ALL OPERATIONS MUST BE READ-ONLY ⚠️

Claude independent analysis → Codex third-perspective confirmation → Integrated verdict

Tool safety note: allowed-tools includes Bash for curl/log queries. Read-only enforcement is behavioral — all commands MUST be reviewed against references/safety-rules.md before execution. Codex independently verifies compliance at P5.

Degradation Matrix

Auto-detect from references/environments.md configuration:

Level Available Resources P3 API P4 Observation Confidence Cap
L4 API + Log + Metrics Full Log + Metrics High
L3 API + Log Full Log only High
L2-API API only Full Response-only Medium
L2-OBS Log only (API unreachable) Skip Time-window scan Medium
L1 No runtime access Skip P3/P4 Code review only Low

Auto-detection logic (see references/environments.md § Degradation Detection):

API Status Log System Metrics Level
Reachable Yes Yes L4
Reachable Yes No L3
Reachable No L2-API
Unreachable Yes L2-OBS
Unreachable No L1

Fail-closed: If Endpoint Allowlist section is missing, skip P3 (cannot call unverified endpoints). At L1, skip P3 and P4. Provide code-review-based analysis only with Low confidence. At L2-OBS, skip P3 (API unreachable); execute P4 time-window scan and background service observation only.

Read the full file on GitHub · 289 lines

Files

What ships with it

4 files 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. 4d ago First seen · 289 lines · 75 tokens per session scan A 21d6be8696f7

Subscribe to this mod's changes

feature-verify is a skill published in the GitHub repository sd0xdev/sd0x-harness (188 stars, last pushed yesterday), licensed MIT. It adds 75 tokens to every session and 3,198 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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