Ax is a TypeScript-first programming framework for building applications with large language models through typed generation, agents, workflows, and optimization tools. It is intended for developers who want one model for LLM programs across TypeScript, Python, Java, C++, Go, Rust, and other runtimes.
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 ax-llm/ax --skill ax-signaturegit clone --depth 1 https://github.com/ax-llm/axWrote 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/ax-llm/ax/ax-signature)<a href="https://agentmods.dev/skills/ax-llm/ax/ax-signature"><img src="https://agentmods.dev/badge/skills/ax-llm/ax/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/ax-llm/ax/ax-signature"><img src="https://agentmods.dev/badge/skills/ax-llm/ax/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 | $0.05904 |
| Opus 5.5 | $0.00023 | $0.02362 |
| Sonnet 5.5 | $0.00011 | $0.01181 |
| Haiku 4.5 | $0.00006 | $0.00590 |
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 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.
How it starts
The opening of the file, as written. The whole thing — 508 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, details?} |
photo:image (input only) |
| Audio | :audio |
input: AxAudioInput; output: AxChatAudioOutput |
recording:audio, speech:audio |
| File | :file |
{mimeType, data | fileUri, filename?} |
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" |
Media inputs carry the optional keys their chat part declares to the provider or router: an image's details ('high', 'low', or 'auto'; OpenAI's image detail), cache, optimize, and altText; a file's filename (OpenAI rejects inline file data without one), cache, and extractedText; a url's cachedContent and cache; and an audio input's mimeType, sampleRate, channels, cache, transcription, and duration. Other keys stay behind.
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. A datetime's zone can be Z, an offset, UTC/GMT, an IANA name (2024-05-09 14:30 America/New_York), or an abbreviation read at its literal offset all year (PST is -08:00 even in July, EDT is -04:00); ambiguous abbreviations (BST, IST, CST, AST, SST, NST, ECT, GST) and ICU's legacy short IDs are rejected with a correction that asks for an IANA name or an offset. PST/PDT and CDT follow US usage; for Philippine time (PST) or Cuban daylight time (CDT), give an IANA name (Asia/Manila, America/Havana) or a UTC offset. A wall time inside a DST gap is invalid, and one in an overlap takes the earlier instant.
What ships with it
2 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.
- 4d ago Changed d6db8a459ac5
- 5d ago Changed 1040a071b14d
- 7d ago Changed d26eb8111d17
- 8d ago Changed ba3d97c99a31
- 10d ago Changed · +18 lines ce91dd7dd1a5
- 12d ago Changed · +1 lines 09ae2095fcd8
- 14d ago Changed · +8 lines 6ccd89854b31
- 17d ago Changed bee8afdc93c3
- 18d ago Changed 17a4684c80a0
- 19d ago First seen · 481 lines · 57 tokens per session scan A 349f2ba83e29
ax-signature is a skill published in the GitHub repository ax-llm/ax (2,969 stars, last pushed 5d ago), licensed Apache-2.0. It adds 57 tokens to every session and 5,904 once invoked, about $0.0002 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 2026-09-03.
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