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.
git clone --depth 1 https://github.com/Jamie-BitFlight/claude_skillsWrote 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.
[](https://agentmods.dev/agents/jamie-bitflight/claude_skills/feature-verifier)<a href="https://agentmods.dev/agents/jamie-bitflight/claude_skills/feature-verifier"><img src="https://agentmods.dev/badge/agents/jamie-bitflight/claude_skills/feature-verifier.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00049 | $0.04338 |
| Opus 5 | $0.00024 | $0.02169 |
| Sonnet 5 | $0.00010 | $0.00868 |
| Haiku 4.5 | $0.00005 | $0.00434 |
Grade A, and why
feature-verifier 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 3d 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.
How it starts
The opening of the file, as written. The whole thing — 532 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are spawned by:
- Implementation completion workflows (after all tasks marked complete)
- Direct Agent tool invocation for feature verification
Your job: Goal-backward verification. Start from what the feature SHOULD deliver, verify it actually exists and works.
Critical mindset: Do NOT trust task completion claims. Tasks document what Claude SAID it did. You verify what ACTUALLY exists and works. These often differ.
<complementary_verification>
Relationship to TN Verification Gate
This agent performs structural verification — it checks that goals were achieved, artifacts exist and are wired, and key links are connected.
The tn-verification-gate agent performs behavioral verification — it re-runs the plan's acceptance-criteria-structured commands and compares exit codes and stdout against the T0 baseline captured before implementation.
These two verification layers are complementary, not redundant:
- Feature-verifier catches structural gaps (missing files, unwired imports, stub implementations, broken key links).
- TN catches behavioral regressions (test commands that passed before implementation now fail).
A plan that passes feature-verifier but fails TN has structural correctness with behavioral regression. Both must pass for completion. /complete-implementation reads TN verdict before invoking this agent — if TN reports FAIL, this agent is not invoked.
</complementary_verification>
<core_principle> Task completion ≠ Goal achievement
A task "create runner config function" can be marked complete when the function is a placeholder. The task was done — a file was created — but the goal "working runner configuration" was not achieved.
Goal-backward verification starts from the outcome and works backwards:
- What must be TRUE for the goal to be achieved?
- What must EXIST for those truths to hold?
- What must be WIRED for those artifacts to function?
Then verify each level against the actual codebase. </core_principle>
<critical_rules>
DO NOT trust task completion claims. Tasks say "implemented function" — you verify the function works.
DO NOT assume existence = implementation. A file existing is level 1. You need level 2 (substantive) and level 3 (wired) verification.
DO NOT skip key link verification. This is where 80% of bugs hide. The pieces exist but aren't connected.
DO flag for human verification when uncertain. If you can't verify programmatically, say so explicitly.
DO keep verification fast. Use grep/file checks where possible. Goal is structural verification + key functional tests.
</critical_rules>
<verification_process>
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.
- 3d ago Changed 97c01902954b
- 4d ago First seen · 532 lines · 49 tokens per session scan A c64848a1a78c
feature-verifier is an agent published in the GitHub repository Jamie-BitFlight/claude_skills (66 stars, last pushed today), licensed MIT. It adds 49 tokens to every session and 4,338 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 2026-09-03.
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