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/tesslio/spec-driven-development-tile/spec-verificationnpx skills add tesslio/spec-driven-development-tile --skill spec-verificationgit clone --depth 1 https://github.com/tesslio/spec-driven-development-tileWrote 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/tesslio/spec-driven-development-tile/spec-verification)<a href="https://agentmods.dev/skills/tesslio/spec-driven-development-tile/spec-verification"><img src="https://agentmods.dev/badge/skills/tesslio/spec-driven-development-tile/spec-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 | $0.00085 | $0.00814 |
| Opus 5 | $0.00043 | $0.00407 |
| Sonnet 5 | $0.00017 | $0.00163 |
| Haiku 4.5 | $0.00009 | $0.00081 |
Grade A, and why
spec-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 4d 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 — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Spec Verification
Ensure code and tests still reflect the documented requirements. Detect and fix drift between specs, implementation, and tests.
When to use
- After implementation is complete (before marking work as done)
- When reviewing PRs that touch spec-covered code
- When
work-reviewflags potential spec drift - Periodically as a maintenance check
Steps
-
Find all specs. Locate
.spec.mdfiles in the project'sspecs/directory:find specs/ -name "*.spec.md" 2>/dev/null -
Validate structural integrity. For each spec, check that links resolve:
- Verify each
targets:path exists (expand globs, confirm matches) - Verify each
[@test]link points to an existing test file - Confirm frontmatter has
name,description, and at least one target
# Use the bundled validation scripts: ./scripts/validate-specs.sh specs/ ./scripts/check-spec-links.sh specs/If either script reports failures, record them as broken-link findings.
- Verify each
-
Run linked tests. Execute the test files referenced by
[@test]links:# Extract test paths from specs and run them grep -rh '\[@test\]' specs/*.spec.md | sed 's/.*\[@test\] *//' | sed 's/`$//'If tests fail, diagnose the failure. Determine whether the test, the code, or the spec is wrong before proceeding.
-
Spot-check targets for drift. Read the files listed in
targets:and compare against spec requirements:- For each requirement in the spec, confirm the target file implements it
- Look for logic in target files that contradicts the spec (edge cases, error handling, data contracts)
- Look for new behavior in target files not mentioned in any spec
-
Check for drift signals:
- Behavioral changes in code not mentioned in the spec
- Newly added tests without matching requirements (or vice versa)
- Deleted or renamed files that still appear in
targets:or[@test]links - New code paths in target files that aren't covered by any requirement
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.
- 4d ago First seen · 87 lines · 85 tokens per session scan A f82db5b89277
spec-verification is a skill published in the GitHub repository tesslio/spec-driven-development-tile (53 stars, last pushed 5mo ago), licensed MIT. It adds 85 tokens to every session and 814 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 2026-08-30.
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