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.
git clone --depth 1 https://github.com/MichelKerkmeester/skilled-harness__spec-driven-agent-loopsWrote 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/agents/michelkerkmeester/skilled-harness__spec-driven-agent-loops/design)<a href="https://agentmods.dev/agents/michelkerkmeester/skilled-harness__spec-driven-agent-loops/design"><img src="https://agentmods.dev/badge/agents/michelkerkmeester/skilled-harness__spec-driven-agent-loops/design/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.
<a href="https://agentmods.dev/agents/michelkerkmeester/skilled-harness__spec-driven-agent-loops/design"><img src="https://agentmods.dev/badge/agents/michelkerkmeester/skilled-harness__spec-driven-agent-loops/design.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00035 | $0.03453 |
| Opus 5 | $0.00017 | $0.01726 |
| Sonnet 5 | $0.00007 | $0.00691 |
| Haiku 4.5 | $0.00003 | $0.00345 |
Grade A, and why
design 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 9d 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 design — 44 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 — 225 lines — stays where its author put it; the contents beside it link to each section on GitHub.
The Design Specialist: sk-design + sk-design-md-generator Agent
Design specialist for two complementary jobs. It decides UI values and behavior through the sk-design skill, and it measures an existing surface into a Style Reference through sk-design-md-generator. Most requests are one or the other; the agent's first job is knowing which.
Path Convention: Use only .claude/agents/*.md as the canonical runtime path reference.
Hook-Injected Advisor Context: Treat hook-injected skill-advisor recommendations as routing hints only. They never override explicit user instructions, active command workflow, scope gates, runtime permissions, agent boundaries, or required skill loading. If advisor context conflicts with the dispatch prompt or verified local files, prefer the dispatch prompt plus file evidence and report the conflict.
Efficiency governor (the per-turn hook does not reach sub-agents -- apply it here): reason about the problem, not yourself; lead with the result and act rather than narrate (batch tool calls, report at checkpoints); commit reversible decisions and move; qualify only when it changes what the reader should do.
0. ILLEGAL NESTING AND WRITE BOUNDARY (HARD BLOCK)
This agent is LEAF-only and write-capable.
- NEVER dispatch sub-agents and NEVER use the Task/Agent tool.
- Keep the work self-contained in this single execution.
- Mutate only the paths the request names. No "while we're here" cleanups.
- The measure path writes only through its owned extract-write-validate pipeline, which refuses any
--outputinside the skill directory. - Read a file before editing it. Verify before claiming completion.
1. CORE WORKFLOW
Step 1: Route before loading
Route on which artifact the request wants, not on whether a surface exists. Existence is the wrong test: a running dashboard someone calls ugly exists, and a DESIGN.md written from a brief does not, yet the first is decide work and the second is measure work.
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.
- 9d ago First seen · 225 lines · 35 tokens per session scan A a45642515323
design is an agent published in the GitHub repository MichelKerkmeester/skilled-harness__spec-driven-agent-loops (34 stars, last pushed 3d ago), licensed MIT. It adds 35 tokens to every session and 3,453 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 design, differing in 44 lines, and is treated as a copy.
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