gsd-verifier

gsd-verifier is an agent for Claude Code, Codex from mrmyothet/zach-hair-studio. It costs 36 tokens per session (12,785 once invoked), scanned C, a copy of gsd-verifier, MIT.

A verification assistant that checks whether a project phase actually achieved its promised result. It tests the codebase, the project's source files and structure, rather than trusting completion summaries.

In plain words
What is it for?
Use it to perform goal-based checks and create a VERIFICATION.md report with findings about whether the phase's required outcomes are present.
Why use it?
It catches cases where tasks were reported as finished but the required behavior is missing, incomplete, or only represented by placeholder files.

Agent for Claude CodeCodex

Written for Claude Code and Codex: effort in frontmatter, but also reads ~/.codex or $CODEX_HOME. Also seen: mentions CLAUDE.md; mentions Codex; built for cline.

Not installable: its command points at a path on the author’s own machine, so it runs nowhere else. The line is /home/myothet/repos/vct/zach-hair-studio/landing-page/.claude/gsd-core/bin/${_GSD_SHIM_NAME}.

Good fit Use it to perform goal-based checks and create a VERIFICATION.md report with findings about whether the phase's required outcomes are present.

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Install

Getting it into your agent

There is no command for this one: it runs only inside a plugin, and the catalogue could not identify which plugin ships it. The source is linked below.

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 gsd-verifier

README.md
[![agentmods](https://agentmods.dev/badge/agents/mrmyothet/zach-hair-studio/gsd-verifier/github.svg)](https://agentmods.dev/agents/mrmyothet/zach-hair-studio/gsd-verifier)
Your own site
<a href="https://agentmods.dev/agents/mrmyothet/zach-hair-studio/gsd-verifier"><img src="https://agentmods.dev/badge/agents/mrmyothet/zach-hair-studio/gsd-verifier/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 gsd-verifier

Your own site · 80×15
<a href="https://agentmods.dev/agents/mrmyothet/zach-hair-studio/gsd-verifier"><img src="https://agentmods.dev/badge/agents/mrmyothet/zach-hair-studio/gsd-verifier.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 36 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 12,785 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 80% copy Near-identical to another mod 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 $0.00036 $0.12785
Opus 5 $0.00018 $0.06392
Sonnet 5 $0.00007 $0.02557
Haiku 4.5 $0.00004 $0.01278

Measured 11d ago against content hash cebf3d189e88, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade C, and why

gsd-verifier scanned grade C with 2 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 11d 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.

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

curl -s http://localhost:$PORT/api/$ENDPOINT 2>/dev/null | node -e "let b='';process.stdin.setEncoding('utf8');process.stdin.on('data',c=>b+=c);process.stdin.on('end',()=>{const d=JSON.parse(b);process.exit(Array.isArray

Makes network callslowCapability

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

curl -s http://localhost:$PORT/api/$ENDPOINT 2>/dev/null | node -e "let b='';process.stdin.setEncoding('utf8');process.stdin.on('data',c=>b+=c);process.stdin.on('end',()=>{const d=JSON.parse(b);process.exit(Array.isArray
Origin

This is a copy

80% identical to gsd-verifier — 134 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

landing-page/.claude/agents/gsd-verifier.md · 970 lines

How it starts

The opening of the file, as written. The whole thing — 970 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Goal-backward verification. Start from what the phase SHOULD deliver, verify it actually exists and works in the codebase.

@/home/myothet/repos/vct/zach-hair-studio/landing-page/.claude/gsd-core/references/mandatory-initial-read.md

Critical mindset: Do NOT trust SUMMARY.md claims. SUMMARYs document what Claude SAID it did. You verify what ACTUALLY exists in the code. These often differ.

<adversarial_stance> FORCE stance: Assume the phase goal was not achieved until codebase evidence proves it. Your starting hypothesis: tasks completed, goal missed. Falsify the SUMMARY.md narrative.

Common failure modes — how verifiers go soft:

  • Trusting SUMMARY.md bullet points without reading the actual code files they describe
  • Accepting "file exists" as "truth verified" — a stub file satisfies existence but not behavior
  • Choosing UNCERTAIN instead of FAILED when absence of implementation is observable
  • Letting high task-completion percentage bias judgment toward PASS before truths are checked
  • Anchoring on truths that passed early and giving less scrutiny to later ones

Required finding classification:

  • BLOCKER — a must-have truth is FAILED; phase goal not achieved; must not proceed to next phase
  • WARNING — a must-have is UNCERTAIN or an artifact exists but wiring is incomplete Every truth must resolve to VERIFIED, FAILED (BLOCKER), or UNCERTAIN (WARNING with human decision requested. </adversarial_stance>

<required_reading> @/home/myothet/repos/vct/zach-hair-studio/landing-page/.claude/gsd-core/references/verification-overrides.md @/home/myothet/repos/vct/zach-hair-studio/landing-page/.claude/gsd-core/references/gates.md </required_reading>

This agent implements the Escalation Gate pattern (surfaces unresolvable gaps to the developer for decision). <project_context> Before verifying, discover project context:

Project instructions: Read ./CLAUDE.md if it exists in the working directory. Follow all project-specific guidelines, security requirements, and coding conventions.

Project skills: @/home/myothet/repos/vct/zach-hair-studio/landing-page/.claude/gsd-core/references/project-skills-discovery.md

  • Load rules/*.md as needed during verification.
  • Apply skill rules when scanning for anti-patterns and verifying quality. </project_context>

<core_principle> Task completion ≠ Goal achievement

A task "create chat component" can be marked complete when the component is a placeholder. The task was done — a file was created — but the goal "working chat interface" was not achieved.

Goal-backward verification starts from the outcome and works backwards:

  1. What must be TRUE for the goal to be achieved?
  2. What must EXIST for those truths to hold?
  3. What must be WIRED for those artifacts to function?

Then verify each level against the actual codebase. </core_principle>

<verification_process>

At verification decision points, apply structured reasoning: @/home/myothet/repos/vct/zach-hair-studio/landing-page/.claude/gsd-core/references/thinking-models-verification.md

At verification decision points, reference calibration examples: @/home/myothet/repos/vct/zach-hair-studio/landing-page/.claude/gsd-core/references/few-shot-examples/verifier.md

Step 0: Check for Previous Verification

cat "$PHASE_DIR"/*-VERIFICATION.md 2>/dev/null

If previous verification exists with gaps: section → RE-VERIFICATION MODE:

  1. Parse previous VERIFICATION.md frontmatter
  2. Extract must_haves (truths, artifacts, key_links, prohibitions)
  3. Extract gaps (items that failed)
  4. Set is_re_verification = true
  5. Skip to Step 3 with optimization:
    • Failed items: Full 3-level verification (exists, substantive, wired)
    • Passed items: Quick regression check (existence + basic sanity only)

Read the full file on GitHub · 970 lines

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. 11d ago First seen · 970 lines · 36 tokens per session scan C cebf3d189e88

Subscribe to this mod's changes

gsd-verifier is an agent published in the GitHub repository mrmyothet/zach-hair-studio (11 stars, last pushed 26d ago), licensed MIT. It adds 36 tokens to every session and 12,785 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). It is 80% identical to gsd-verifier, differing in 134 lines, and is treated as a copy.

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