gap-analysis

gap-analysis is a skill for Claude Code from MichaelYcJo/SpecSeal. It costs 101 tokens per session (1,256 once invoked), scanned A, original, MIT.

A comparison between a written design and the software that was built. It checks what callers can use, how data is stored, and whether the implemented rules match the document.

In plain words
What is it for?
Use it to compare APIs, command-line interfaces, screens, queues, libraries, data models, migrations, validation, and error handling with their specification.
Why use it?
It exposes missing work, unrequested additions, and behavior that differs from the design. This helps teams find implementation drift before it causes confusion or rework.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the specseal plugin — 23 skills, 3 agents, 3 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/michaelycjo/specseal/gap-analysis
Any agent
npx skills add MichaelYcJo/SpecSeal --skill gap-analysis
Clone the repo
git clone --depth 1 https://github.com/MichaelYcJo/SpecSeal

Made for: Claude Code.

Or install specseal, the plugin that ships this one along with the rest of its 23 skills, 3 agents, 3 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 gap-analysis

README.md
[![agentmods](https://agentmods.dev/badge/skills/michaelycjo/specseal/gap-analysis.svg)](https://agentmods.dev/skills/michaelycjo/specseal/gap-analysis)
Your own site
<a href="https://agentmods.dev/skills/michaelycjo/specseal/gap-analysis"><img src="https://agentmods.dev/badge/skills/michaelycjo/specseal/gap-analysis.svg" alt="Measured on agentmods" height="20"></a>
Per session 101 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,256 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 5.1 $0.00101 $0.01256
Opus 5 $0.00051 $0.00628
Sonnet 5 $0.00020 $0.00251
Haiku 4.5 $0.00010 $0.00126

Measured 5d ago against content hash fc1bed628eb4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

gap-analysis 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 5d 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.

skills/gap-analysis/SKILL.md · 127 lines

How it starts

The opening of the file, as written. The whole thing — 127 lines — stays where its author put it; the contents beside it link to each section on GitHub.

gap-analysis — how far the build drifted from the document

A design document and the code it produced diverge in three directions, and only one of them is obvious. Missing is easy to see. Extra — built but never specified — and divergent — built to a different rule than written — are what this looks for.

Comparison dimensions

Four kinds, whatever the project is. The examples name a web service because that is the common case, not because it is the only one — substitute the equivalent and the dimension still holds.

  1. The surface others touch — whatever a caller reaches for, and what comes back. HTTP paths, methods and status codes; a CLI's flags, exit codes and stdout shape; a library's exported names and signatures; a screen's controls and states; a queue's topics and message shapes.

  2. The shape of what persists — entities and relationships, field names, types and constraints, and how existing data gets to the new shape. Tables and migrations; a file format and its version field; cache keys and their expiry; what a client keeps on disk between launches.

  3. The rules that decide — feature completeness, edge cases, error scenarios, validation. This dimension is the same everywhere and is usually where the real divergence hides, because it is the one a document describes in prose rather than in a table.

  4. Conventions — naming, folder structure, import patterns, error message format. Drift here is rarely a defect on its own; it is the signal that the document stopped being read partway through.

If a dimension does not apply — a pure library persists nothing — say so and move on. Recording it as a match claims a walk you did not make; leaving it out silently makes a partial walk look complete.

Verdicts

Per item, one of four. These are the useful part and they stay:

  • Match — implemented as designed
  • Partial — implemented differently; say how
  • Missing — not implemented
  • Extra — implemented, not in this document. That is not the same as unspecified: a repository accumulates specifications, and the second one routinely authorises what the first never mentioned. Say where else you looked before calling it unspecified

Read the full file on GitHub · 127 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. 5d ago First seen · 127 lines · 101 tokens per session scan A fc1bed628eb4

Subscribe to this mod's changes

gap-analysis is a skill published in the GitHub repository MichaelYcJo/SpecSeal (1 stars, last pushed today), licensed MIT. It adds 101 tokens to every session and 1,256 once invoked, about $0.0005 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 2026-08-31.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

local-ai-agents

Build local-first AI agents that run entirely on a developer workstation with Microsoft Foundry Local and Qwen function-calling models. Covers Small Language Models (SLMs), the OpenAI-compatible local endpoint, sandboxed local tools, local RAG with Chroma, local MCP servers, hybrid cloud/local routing, and the…

microsoft/ai-agents-for-beginners · 200 tokens

chronicle

Analyze Copilot session history for standup reports, usage tips, session search, and session reindexing. Use when the user asks for a standup, daily summary, usage tips, workflow recommendations, wants to search or find past sessions by keyword/file/PR, wants to reindex their session store, or asks about deleting…

microsoft/vscode · 72 tokens

chat-pet-sprite-creation

Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.

microsoft/vscode · 53 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens

next-cache-components-adoption

Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…

vercel/next.js · 95 tokens