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 skills add AdamBien/airails --skill capability-briefgit clone --depth 1 https://github.com/AdamBien/airailsWrote 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/adambien/airails/capability-brief)<a href="https://agentmods.dev/skills/adambien/airails/capability-brief"><img src="https://agentmods.dev/badge/skills/adambien/airails/capability-brief/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/skills/adambien/airails/capability-brief"><img src="https://agentmods.dev/badge/skills/adambien/airails/capability-brief.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 | $0.00235 | $0.02136 |
| Opus 5.5 | $0.00094 | $0.00854 |
| Sonnet 5.5 | $0.00047 | $0.00427 |
| Haiku 4.5 | $0.00023 | $0.00214 |
Grade A, and why
capability-brief 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 2d 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 — 93 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Produce a brief: one filled template that answers every question /sbce new would otherwise
ask while authoring a capability spec. The interview new runs against a vague feature description
is moved here, to the moment the domain owner is present, and its answers are recorded once. new
then authors instead of asks.
The brief is stack-neutral: what the system promises, never how it is built. No types, transports, frameworks, endpoints, or file names — the stack skill owns those, and a brief that names them would bind the spec to an implementation before the spec exists.
Two guarantees, one of them yours
- Structural completeness is yours to enforce. Every section filled, every actor step named as an operation, every input with its parts, every operation with its failure cases. The checklist below makes this mechanical; do not emit a brief that fails it.
- Semantic completeness is the human's. The result shape, which parts of an input are required, what a second identical request does, which alternative was rejected — these are domain facts. You cannot invent them; you can only ask until they are answered or honestly parked under
## Open issues. A silently guessed answer becomes a spec statement, then a test, then code that verifies your guess instead of their intent.
Invocation modes: uc · story · review
Read the mode and the input from the invocation: /capability-brief uc "<description>",
/capability-brief story "<description>", /capability-brief review <file-or-pasted-brief>.
With the mode omitted, pick the format by the routing rule below and say which one you chose.
| Mode | Brief | When | Template |
|---|---|---|---|
uc |
Use case | a new capability; several steps or actors; state kept across calls | references/use-case-template.md |
story |
User story | one behaviour added to an existing capability; a new capability with a single operation | references/user-story-template.md |
review |
either | an existing brief to check; the format is the one the brief already has | — |
What ships with it
3 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.
- 2d ago Changed · -40 tokens per session c1c3f4c62685
- 18d ago First seen · 93 lines · 275 tokens per session scan A f99f74bc9c0d
capability-brief is a skill published in the GitHub repository AdamBien/airails (58 stars, last pushed 3d ago), licensed MIT. It adds 235 tokens to every session and 2,136 once invoked, about $0.0009 per session on Opus 5.5. 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 2026-09-29.
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