gsd-verifier

gsd-verifier is an agent for Claude Code from markmocasa-boop/n8n-mcp-czlon. It costs 36 tokens per session (5,723 once invoked), scanned A, a copy of gsd-verifier, MIT.

A verification agent that checks whether a completed development phase actually achieved its promised result.

In plain words
What is it for?
It works backward from the goal, verifies required truths and artifacts in the codebase, and creates a VERIFICATION.md report, including re-checks after gaps are fixed.
Why use it?
It avoids treating finished tasks or claims in SUMMARY.md as proof that the software works. It checks the real code, its connections, and the behavior required by the phase goal.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: positional $N argument.

Good fit It works backward from the goal, verifies required truths and artifacts in the codebase, and creates a VERIFICATION.md report, including re-checks after gaps are fixed.

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Install with agentmods
npx agentmods add agents/markmocasa-boop/n8n-mcp-czlon/gsd-verifier
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.

Clone the repo
git clone --depth 1 https://github.com/markmocasa-boop/n8n-mcp-czlon

Made for: Claude Code.

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/markmocasa-boop/n8n-mcp-czlon/gsd-verifier/github.svg)](https://agentmods.dev/agents/markmocasa-boop/n8n-mcp-czlon/gsd-verifier)
Your own site
<a href="https://agentmods.dev/agents/markmocasa-boop/n8n-mcp-czlon/gsd-verifier"><img src="https://agentmods.dev/badge/agents/markmocasa-boop/n8n-mcp-czlon/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/markmocasa-boop/n8n-mcp-czlon/gsd-verifier"><img src="https://agentmods.dev/badge/agents/markmocasa-boop/n8n-mcp-czlon/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 5,723 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 100% 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 $0.05723
Opus 5 $0.00018 $0.02861
Sonnet 5 $0.00007 $0.01145
Haiku 4.5 $0.00004 $0.00572

Measured 11d ago against content hash cb1f1452d7fb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

gsd-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 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.

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.

Origin

This is a copy

100% identical to gsd-verifier — 0 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.

gsd/agents/gsd-verifier.md · 779 lines

How it starts

The opening of the file, as written. The whole thing — 779 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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

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.

<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>

Step 0: Check for Previous Verification

Before starting fresh, check if a previous VERIFICATION.md exists:

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)
  3. Extract gaps (items that failed)
  4. Set is_re_verification = true
  5. Skip to Step 3 (verify truths) with this optimization:
    • Failed items: Full 3-level verification (exists, substantive, wired)
    • Passed items: Quick regression check (existence + basic sanity only)

If no previous verification OR no gaps: section → INITIAL MODE:

Set is_re_verification = false, proceed with Step 1.

Step 1: Load Context (Initial Mode Only)

Gather all verification context from the phase directory and project state.

# Phase directory (provided in prompt)
ls "$PHASE_DIR"/*-PLAN.md 2>/dev/null
ls "$PHASE_DIR"/*-SUMMARY.md 2>/dev/null

# Phase goal from ROADMAP
grep -A 5 "Phase ${PHASE_NUM}" .planning/ROADMAP.md

# Requirements mapped to this phase
grep -E "^| ${PHASE_NUM}" .planning/REQUIREMENTS.md 2>/dev/null

Read the full file on GitHub · 779 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 · 779 lines · 36 tokens per session scan A cb1f1452d7fb

Subscribe to this mod's changes

gsd-verifier is an agent published in the GitHub repository markmocasa-boop/n8n-mcp-czlon (0 stars, last pushed 1mo ago), licensed MIT. It adds 36 tokens to every session and 5,723 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to gsd-verifier, differing in 0 lines, and is treated as a copy.

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