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/mracal/vibe-engineering/spec-syncnpx skills add mracal/vibe-engineering --skill spec-syncgit clone --depth 1 https://github.com/mracal/vibe-engineeringWrote 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/mracal/vibe-engineering/spec-sync)<a href="https://agentmods.dev/skills/mracal/vibe-engineering/spec-sync"><img src="https://agentmods.dev/badge/skills/mracal/vibe-engineering/spec-sync.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 | $0.00046 | $0.01613 |
| Opus 5 | $0.00023 | $0.00807 |
| Sonnet 5 | $0.00009 | $0.00323 |
| Haiku 4.5 | $0.00005 | $0.00161 |
Grade A, and why
vibe-spec-sync 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.
This is a copy
100% identical to vibe-spec-sync — 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.
How it starts
The opening of the file, as written. The whole thing — 147 lines — stays where its author put it; the contents beside it link to each section on GitHub.
vibe-spec-sync
Code changes. Specs don't update themselves. This skill closes the loop.
When to Use This Skill
- Before committing — detect spec drift from staged changes
- After approving decisions (from
vibe-decision-journal) — sync them back to spec - When
vibe-spec-vs-code-auditfound gaps — fix them - Periodically — ensure spec still reflects reality
When NOT to Use This Skill
- No spec exists (write one first, or use
vibe-doc-quality-gateto bootstrap) - Prototype/spike code with no spec commitment
- Spec is explicitly labeled as aspirational/future-state
Prerequisites
The project must have:
- A specification document (markdown) — configured in step 1
- Implementation code that the spec describes
- Optionally: a test suite with requirement traceability markers (
# req:[ID])
Steps
Step 1: Locate Spec and Code
-
Find the spec — Look for:
spec.md,SPEC.md,*_spec.mdin project root ordocs/- Design docs in
docs/design/,docs/architecture/ - Ask user if ambiguous: "Which document is the authoritative spec?"
-
Find the implementation — The code files the spec describes
-
Find the decision log —
docs/decisions/decisions.jsonl(fromvibe-decision-journal)
Step 2: Extract Drift from Staged Changes
Run git diff --cached and analyze what changed relative to the spec:
-
Categorize each change:
- Spec-aligned: Change matches what the spec says → no action
- Spec-extending: Change adds behavior the spec doesn't mention → spec needs new section
- Spec-modifying: Change alters behavior the spec describes differently → spec needs update
- Spec-contradicting: Change violates what the spec explicitly forbids → flag for review
-
For each drift item, produce:
DRIFT-[NNN]: Type: extending | modifying | contradicting Spec section: "## [Header]" Current spec says: "[quoted text]" Code now does: "[description of new behavior]" Suggested spec update: "[proposed new text]"
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 · 147 lines · 46 tokens per session scan A e1eba302006e
vibe-spec-sync is a skill published in the GitHub repository mracal/vibe-engineering (3 stars, last pushed 4d ago), licensed MIT. It adds 46 tokens to every session and 1,613 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 vibe-spec-sync, differing in 0 lines, and is treated as a copy.
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