ax-java-playbook

A Java coding guide for Ax playbooks, which are evolving sets of context or rules attached to an agent or program. It covers learning from verified run feedback, updating the playbook, and inserting it into program context.

In plain words
What is it for?
Use it to seed or evolve an Ax playbook, learn avoidance rules from failures, refine it from examples or live feedback, and render or save it for later runs.
Why use it?
It helps agents retain grounded lessons from earlier runs while allowing changes to be checked and rolled back exactly.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/ax-llm/ax/ax-java-playbook
Any agent
npx skills add ax-llm/ax --skill ax-java-playbook
Clone the repo
git clone --depth 1 https://github.com/ax-llm/ax

Made for: Claude Code, Codex.

Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 503 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00050 $0.00503
Opus 5 $0.00025 $0.00251
Sonnet 5 $0.00010 $0.00101
Haiku 4.5 $0.00005 $0.00050

Measured today against content hash 728a6d9ed8d1, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ax-java-playbook 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 today.

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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

packages/java/skills/ax-java-playbook/SKILL.md · 47 lines

What it actually says

Ax Playbook For Java

This skill helps an agent write Java code with the generated Ax package dev.axllm:ax. Use the generated package API, examples, and manifests; do not import TypeScript-only APIs unless you are editing the TypeScript package.

When To Use

  • Grow an evolving context playbook for a program or agent stage with playbook().
  • Attach a seed playbook to an agent and learn bounded avoidance rules from run-end failure signals.
  • Use the agent-bound playbook evolve method to mine grounded weaknesses with verification and exact rollback.
  • Refine a playbook online from live feedback or offline from labeled examples.
  • Render or persist a playbook and inject it into a program context.

Package Facts

  • Language: Java.
  • Package: dev.axllm:ax.
  • Package API docs: API.md and axir-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

AxGen program = Ax.ax("question:string -> answer:string");
AxPlaybook pb = Ax.playbook(program, java.util.Map.of("studentAI", llm));
pb.evolve(examples, metricFn, java.util.Map.of());

Relevant API Surface

  • Optimizers: Ax.optimize, Ax.playbook, AxPlaybook, AxBootstrapFewShot, AxGEPA, OptimizerEngine, OptimizerEvaluator

Guardrails

  • Start from package examples for exact native syntax before inventing a new call shape.
  • Use provider-api examples only when the user explicitly has provider credentials available.
  • Use no-key examples for deterministic local checks and provider request mapping.
  • Treat AxIR as the source of generated package truth: if package docs disagree with source code, update the compiler and regenerate packages.
  • Do not copy repo-maintainer skills from tools/*/skills/ into user packages.
Changes

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.

  1. today Changed 728a6d9ed8d1
  2. 3d ago First seen · 47 lines · 50 tokens per session scan A 32b6c15b07e4

Subscribe to this mod's changes

ax-java-playbook is a skill published in the GitHub repository ax-llm/ax (2,890 stars, last pushed 2d ago), licensed Apache-2.0. It adds 50 tokens to every session and 503 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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