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-cpp-typesafegit 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-cpp-typesafe)<a href="https://agentmods.dev/skills/ax-llm/ax/ax-cpp-typesafe"><img src="https://agentmods.dev/badge/skills/ax-llm/ax/ax-cpp-typesafe/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-cpp-typesafe"><img src="https://agentmods.dev/badge/skills/ax-llm/ax/ax-cpp-typesafe.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 | $0.00057 | $0.02009 |
| Opus 5.5 | $0.00023 | $0.00804 |
| Sonnet 5.5 | $0.00011 | $0.00402 |
| Haiku 4.5 | $0.00006 | $0.00201 |
Grade A, and why
ax-cpp-typesafe 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 yesterday.
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.
Copies of this mod
4 near-identical copies found in the catalogue:
- ax-rust-typesafe — 94% identical, 31 lines differ
- ax-python-typesafe — 86% identical, 30 lines differ
- ax-java-typesafe — 83% identical, 32 lines differ
- ax-go-typesafe — 78% identical, 34 lines differ
How it starts
The opening of the file, as written. The whole thing — 81 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Typesafe / Jev For C++
This skill helps an agent write C++ code with the generated Ax package axllm. Use the generated package API, examples, and manifests; do not import TypeScript-only APIs unless you are editing the TypeScript package.
When To Use
- Use Jev for typed decisions with ordinary Ax signatures.
- Retain probabilities and scores through evidence-bearing AxGen signatures; use native questions for advanced criteria or structured state.
- Compose a separate generative program for prose or tools.
Package Facts
- Language: C++.
- Package:
axllm. - Package API docs:
API.mdandaxir-api.json. - Capability manifest:
axir-capabilities.json. - Runnable examples:
examples/. - Real network support: yes.
- Scripted no-key transport support: yes.
- Runtime profiles:
javascript-quickjs,python-pyodide.
Core Pattern
auto model = axllm::ai("typesafe", axllm::object({{"api_key", api_key}, {"trueThreshold", 0.9}}));
auto triage = axllm::ax("ticket:string -> urgent:boolean(true \"Core task blocked\", false \"Routine request\"), team:class \"support, billing, engineering\"");
auto decision = triage.forward(*model, axllm::object({{"ticket", ticket}}));
Decision evidence
Add (evidence) to boolean/class/score/box signature outputs to retain probabilities, values, provenance, and native class/score confidence through AxGen. Boolean threshold 0.7 is local to that field; scalar fields still use provider trueThreshold. A plain score returns a continuous zero-based rubric index.
Native selected classes and continuous scores are preserved, even when they differ from argmax or a weighted mean. Generative providers elicit probabilities, derive values locally, omit confidence, and use provenance.source=elicited. Ax attaches actual provider/model provenance. The result shape does not make confidence or calibration comparable across models.
By default a decision refusal raises a terminal AxDecisionRefusalError without correction retries. Use (evidence, refusal return) for an answered/refused union. Generated-language error envelopes retain the decision error type. Arrays, optional fields and nested evidence work with generative models; native providers require flat required scalar fields. Streaming emits only complete evidence. Label-only examples never manufacture distributions.
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.
- yesterday Changed · +6 lines · -1 tokens per session 72e076a6272a
- 3d ago Changed c4133f876ba2
- 5d ago Changed · +10 lines · +9 tokens per session 25e481f8ed8f
- 8d ago Changed e78c6f8be5ce
- 9d ago Changed 3e2bbe5642ea
- 10d ago Changed 3ac9c735093b
- 16d ago Changed 1d50f2f5df6f
- 19d ago Changed 102087e58301
- 21d ago Changed 763ea8978aa7
- 24d ago First seen · 65 lines · 49 tokens per session scan A 089f7d3bfbaf
ax-cpp-typesafe is a skill published in the GitHub repository ax-llm/ax (2,967 stars, last pushed 2d ago), licensed Apache-2.0. It adds 57 tokens to every session and 2,009 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 2026-09-19.
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