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.
npx agentmods add skills/uta2000/feature-flow/design-verificationnpx skills add uta2000/feature-flow --skill design-verificationgit clone --depth 1 https://github.com/uta2000/feature-flowWrote 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/skills/uta2000/feature-flow/design-verification)<a href="https://agentmods.dev/skills/uta2000/feature-flow/design-verification"><img src="https://agentmods.dev/badge/skills/uta2000/feature-flow/design-verification.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 | $0.00084 | $0.06355 |
| Opus 5 | $0.00042 | $0.03178 |
| Sonnet 5 | $0.00017 | $0.01271 |
| Haiku 4.5 | $0.00008 | $0.00636 |
Grade A, and why
design-verification 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 — 398 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Design Verification
Verify a design document against the actual codebase to catch conflicts, gaps, and incorrect assumptions before implementation. This is the gate between "this sounds right" and "this will actually work."
Announce at start: "Running design-verification to check this design against the codebase for blockers and gaps."
When to Use
- After writing or updating a design document
- Before creating a GitHub issue from a design
- Before writing an implementation plan
- When the user asks "will this work with our app?"
Process
Step 1: Load the Design Document
Find the design from the linked GitHub issue:
-
If
issueis in the lifecycle context (the issue number was passed as an argument or set bycreate-issueearlier in the session):gh issue view <issue_number> --json body --jq '.body'Extract the content between
<!-- feature-flow:design:start -->and<!-- feature-flow:design:end -->markers.- If markers are found: use the extracted content as the design document.
- If markers are absent: the design has not been merged into the issue yet. Stop and instruct the user: "No design found in issue #<issue_number>. Run
feature-flow:design-documentfirst to merge the design into the issue." - If the extracted content is a reference link (
Design is too large to inline — see comment: <url>): fetch the comment URL viagh api <url> --jq '.body'and use that content instead.
-
If the user specified a file path directly (legacy support for pre-2026-04-23 design docs in
docs/plans/): Read the file at the specified path. Announce: "Loading design from file (legacy path):<path>." -
Fallback — no issue and no path: Stop and instruct the user: "No design source found. Pass the issue number (
issue: N) or a file path (design_doc: /path/to/doc.md)."
After loading, extract all proposed changes from the design content.
Step 2: Load Project Context
Check for a .feature-flow.yml file in the project root:
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.
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 First seen · 398 lines · 84 tokens per session scan A 491c1de82a30
design-verification is a skill published in the GitHub repository uta2000/feature-flow (4 stars, last pushed 1mo ago), licensed MIT. It adds 84 tokens to every session and 6,355 once invoked, about $0.0004 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.
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