ai-native-cli

A design specification for command-line tools that AI agents use. It defines rules for structured JSON output, input validation, error handling, safety checks, exit codes and built-in descriptions.

In plain words
What is it for?
Use it when creating, modifying or reviewing a CLI for agent use, automation pipelines or machine-checkable compliance.
Why use it?
It helps make command-line tools predictable and safe when an agent calls them automatically, including when the input is invalid or validation fails.

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/beel-collab/presets.dev/ai-native-cli
Any agent
npx skills add beel-collab/presets.dev --skill ai-native-cli
Clone the repo
git clone --depth 1 https://github.com/beel-collab/presets.dev

Made for: Claude Code, Codex.

Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,552 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 95% copy Near-identical to another mod 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 $0.00040 $0.03552
Opus 5 $0.00020 $0.01776
Sonnet 5 $0.00008 $0.00710
Haiku 4.5 $0.00004 $0.00355

Measured 2d ago against content hash 28f07d95b7c4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ai-native-cli 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.

Origin

This is a copy

95% identical to ai-native-cli — 11 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

claude/skills/ai-ml/ai-native-cli/SKILL.md · 317 lines

How it starts

The opening of the file, as written. The whole thing — 317 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent-Friendly CLI Spec v0.1

When building or modifying CLI tools, follow these rules to make them safe and reliable for AI agents to use.

Overview

A comprehensive design specification for building AI-native CLI tools. It defines 98 rules across three certification levels (Agent-Friendly, Agent-Ready, Agent-Native) with prioritized requirements (P0/P1/P2). The spec covers structured JSON output, error handling, input contracts, safety guardrails, exit codes, self-description, and a feedback loop via a built-in issue system.

When to Use This Skill

  • Use when building a new CLI tool that AI agents will invoke
  • Use when retrofitting an existing CLI to be agent-friendly
  • Use when designing command-line interfaces for automation pipelines
  • Use when auditing a CLI tool's compliance with agent-safety standards

Core Philosophy

  1. Agent-first -- default output is JSON; human-friendly is opt-in via --human
  2. Agent is untrusted -- validate all input at the same level as a public API
  3. Fail-Closed -- when validation logic itself errors, deny by default
  4. Verifiable -- every rule is written so it can be automatically checked

Layer Model

This spec uses two orthogonal axes:

  • Layer answers rollout scope: core, recommended, ecosystem
  • Priority answers severity: P0, P1, P2

Use layers for migration and certification:

  • core -- execution contract: JSON, errors, exit codes, stdout/stderr, safety
  • recommended -- better machine UX: self-description, explicit modes, richer schemas
  • ecosystem -- agent-native integration: agent/, skills, issue, inline context

Certification maps to layers:

  • Agent-Friendly -- all core rules pass
  • Agent-Ready -- all core + recommended rules pass
  • Agent-Native -- all layers pass

How It Works

Step 1: Output Mode

Default is agent mode (JSON). Explicit flags to switch:

$ mycli list              # default = JSON output (agent mode)
$ mycli list --human      # human-friendly: colored, tables, formatted
$ mycli list --agent      # explicit agent mode (override config if needed)

Read the full file on GitHub · 317 lines

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. 2d ago First seen · 317 lines · 40 tokens per session scan A 28f07d95b7c4

Subscribe to this mod's changes

ai-native-cli is a skill published in the GitHub repository beel-collab/presets.dev (2 stars, last pushed 3mo ago), licensed MIT. It adds 40 tokens to every session and 3,552 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to ai-native-cli, differing in 11 lines, and is treated as a copy.

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