Borrowing it
Nothing to install: this file belongs to dosco/aithy. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/dosco/aithy/main/.claude/skills/ax-signature/SKILL.mdgit clone --depth 1 https://github.com/dosco/aithyWrote 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/dosco/aithy/ax-signature)<a href="https://agentmods.dev/skills/dosco/aithy/ax-signature"><img src="https://agentmods.dev/badge/skills/dosco/aithy/ax-signature/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/dosco/aithy/ax-signature"><img src="https://agentmods.dev/badge/skills/dosco/aithy/ax-signature.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00057 | $0.04619 |
| Opus 5 | $0.00028 | $0.02309 |
| Sonnet 5 | $0.00011 | $0.00924 |
| Haiku 4.5 | $0.00006 | $0.00462 |
Grade A, and why
ax-signature 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 6d 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 — 422 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Ax Signature Reference
Signature Syntax
[description] input1:type, input2:type -> output1:type, output2:type
Field Types
| Type | Syntax | TypeScript | Example |
|---|---|---|---|
| String | :string |
string |
userName:string |
| Number | :number |
number |
score:number |
| Boolean | :boolean |
boolean |
isValid:boolean |
| JSON | :json |
any |
metadata:json |
| Date | :date |
Date |
birthDate:date |
| DateTime | :datetime |
Date |
timestamp:datetime |
| DateRange | :dateRange |
{ start: Date; end: Date } |
travelDates:dateRange |
| DateTimeRange | :datetimeRange |
{ start: Date; end: Date } |
meetingWindow:datetimeRange |
| Image | :image |
{mimeType, data} |
photo:image (input only) |
| Audio | :audio |
input: AxAudioInput; output: AxChatAudioOutput |
recording:audio, speech:audio |
| File | :file |
{mimeType, data} |
document:file (input only) |
| URL | :url |
string |
website:url |
| Code | :code |
string |
pythonScript:code |
| Class | :class "a, b, c" |
"a" | "b" | "c" |
mood:class "happy, sad" |
Date, datetime, and range fields are AI-friendly but strict. They accept ISO-style values, trim minor whitespace/casing issues, and parse ranges as { "start": "...", "end": "..." }, [start, end], start/end, or natural delimiters like start to end; invalid values and reversed ranges should fail validation rather than being silently autocorrected.
Arrays, Optional, and Internal Fields
'tags:string[] -> processedTags:string[]' // arrays
'query:string, context?:string -> response:string' // optional with ?
'problem:string -> reasoning!:string, solution:string' // internal with !
Extended String Grammar (Modifier Bags + Nested Objects)
The string form is constraint-complete: everything the fluent API expresses (except Standard Schema fields) can be written in the string. A type takes an optional comma-separated, order-free modifier bag in parentheses, and objects declare structured fields inline.
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.
- 6d ago Changed · +115 lines 07a9aad0b016
- 10d ago First seen · 307 lines · 57 tokens per session scan A 06cd528a3060
ax-signature is a skill published in the GitHub repository dosco/aithy (107 stars, last pushed 9d ago), licensed Apache-2.0. It adds 57 tokens to every session and 4,619 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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