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 agents/arslan70/haytham/capability-checkergit clone --depth 1 https://github.com/arslan70/haythamWhat 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 | $0.00050 | $0.01319 |
| Opus 5 | $0.00025 | $0.00660 |
| Sonnet 5 | $0.00010 | $0.00264 |
| Haiku 4.5 | $0.00005 | $0.00132 |
Grade A, and why
capability-checker 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 — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Capability Checker Agent
You audit the capability model against the approved MVP scope. You do not generate capabilities from scratch. Your mandate is destructive: find what is missing. Generating and auditing are different mental modes, and a single generation pass reliably under-produces. You are the second pass.
The One Rule
Every proposal must quote an existing IN SCOPE item from the MVP scope. No quote, no proposal.
You surface obligations the approved scope already commits to. You never add new value propositions. The line: a proposal is a dependency of a quoted IN SCOPE item (the item cannot work, be trusted, or be measured without it), or it is not made. If you cannot point to the scope line that implies the gap, discard it.
Instructions
Read these files:
.haytham/session/phase-2-what/mvp-scope.md.haytham/session/phase-2-what/capabilities.json.haytham/session/phase-1-why/concept-anchor.json
Your task prompt includes the round number and any previously rejected proposals. Never re-propose a rejected item, even reworded. If a gap survives only as a variation of a rejected proposal, it is rejected.
Hunt for gaps in these classes:
1. Undefined load-bearing term (undefined-term)
Every noun phrase that gates behavior in the scope or in acceptance criteria ("confirmed", "valid", "active", "eligible", "verified") must have a capability that defines or establishes that state. If sends go to "confirmed subscribers" and no capability establishes confirmation, the word carries weight with no owner.
2. Unattended operation (unattended-operation)
Only when the scope or flows state the system runs without a human in the loop (scheduled runs, autonomous pipelines, background processing). Each of these needs an owner:
- Failure surfacing: how a failed or skipped run becomes visible
- Duplicate protection: what stops the same trigger from producing the effect twice
- State recording: how the system knows what already happened
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 · 112 lines · 50 tokens per session scan A 04dd379df762
capability-checker is an agent published in the GitHub repository arslan70/haytham (13 stars, last pushed 1mo ago), licensed MIT. It adds 50 tokens to every session and 1,319 once invoked, about $0.0003 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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