AXI: Agent eXperience Interface

10 design principles for building agent-ergonomic apps.

AI agents interact with external services through two dominant paradigms today: CLIs which were originally built for humans, and structured tool protocols like MCP. Both impose significant overhead.

AXI is a new paradigm - agent-native CLI tools built from 10 design principles that treat token budget as a first-class constraint.

Results

Browser Benchmark

Evaluated across 490 runs (14 tasks × 7 conditions × 5 repeats) using Claude Sonnet 4.6:

Condition	Success	Avg Cost	Avg Duration	Avg Turns
chrome-devtools-axi	100%	$0.074	21.5s	4.5
dev-browser	99%	$0.078	28.6s	4.9
agent-browser	99%	$0.088	24.6s	4.8
chrome-devtools-mcp-compressed	100%	$0.091	29.7s	7.6
chrome-devtools-mcp-search	99%	$0.096	29.4s	7.5
chrome-devtools-mcp	99%	$0.101	26.0s	6.2
chrome-devtools-mcp-code	100%	$0.120	36.2s	6.4

GitHub Benchmark

Evaluated across 425 runs (17 tasks × 5 conditions × 5 repeats) using Claude Sonnet 4.6:

Condition	Success	Avg Cost	Avg Duration	Avg Turns
gh-axi	100%	$0.050	15.7s	3
gh (CLI)	86%	$0.054	17.4s	3
GitHub MCP	87%	$0.148	34.2s	6
GitHub MCP + ToolSearch	82%	$0.147	41.1s	8
MCP + Code Mode	84%	$0.101	43.4s	7

Quick Start

Reference AXI implementations:

• gh-axi — GitHub operations
• chrome-devtools-axi — Browser automation

See the full AXI Catalog below for all official and community AXIs.

npm install -g gh-axi
npm install -g chrome-devtools-axi

Add to your CLAUDE.md or AGENTS.md:

Use `gh-axi` for GitHub and `chrome-devtools-axi` for browser automation.

The 10 Principles

These principles define what makes a CLI tool "an AXI":

#	Principle	Summary
1	Token-efficient output	Use TOON format for ~40% token savings over JSON
2	Minimal default schemas	3–4 fields per list item, not 10
3	Content truncation	Truncate large text with size hints and --full escape hatch
4	Pre-computed aggregates	Include aggregated counts and statuses that eliminate round trips
5	Definitive empty states	Explicit "0 results" rather than ambiguous empty output
6	Structured errors & exit codes	Idempotent mutations, structured errors, no interactive prompts
7	Ambient context	Install opt-in session integrations first, then offer an on-demand skill
8	Content first	Running with no arguments shows live data, not help text
9	Contextual disclosure	Include next-step suggestions after each output
10	Consistent way to get help	Concise per-subcommand reference when agents need it

AXI Catalog

Official

Reference implementations maintained by the AXI project, validating the principles across different domains:

AXI	Domain	What it does
gh-axi	GitHub	Issues, PRs, workflow runs, releases, and more. Wraps the official gh CLI with agent-ergonomic output.
chrome-devtools-axi	Browser automation	Navigate, click, fill, and extract with combined operations and query filtering. Wraps chrome-devtools-mcp.
lavish-axi	Human review	Turns agent-generated HTML artifacts into collaborative review surfaces - annotate, comment, and send feedback back to the agent.

Community

AXIs built and maintained by the community:

AXI	Author	Domain	What it does
slack-axi	Jarvus Innovations	Slack	Read, search, sweep, and safely draft Slack messages with token-efficient output.

Built an AXI? Open a PR to add it to this list.

Build Your Own AXI

Install the AXI skill to get the design guidelines and scaffolding for building an AXI-compliant CLI:

npx skills add kunchenguid/axi

This installs the AXI skill - a detailed guide with examples for each principle that your coding agent can reference while building. For your own AXI, expose an explicit setup command for session hooks as the primary integration, then ship an installable Agent Skill as a lower-overhead secondary path. Users only need one path, but hooks and skills complement each other when both are available.

Development

Browser Benchmark

The browser benchmark harness lives in bench-browser/. It compares browser automation tools across 16 browsing tasks.

pnpm install

# Run a single condition × task
pnpm --dir bench-browser run bench -- run --condition chrome-devtools-axi --task read_static_page

# Run the full matrix
pnpm --dir bench-browser run bench -- matrix --repeat 5

# Generate summary report
pnpm --dir bench-browser run bench -- report

# Render the social video
pnpm --dir bench-browser run render:social

The HyperFrames composition for the social asset lives in bench-browser/social/. Edit social/index.html for the animation and render docs/social/rendered/race.mp4 with pnpm --dir bench-browser run render:social.

Published results (490 runs): bench-browser/published-results/report.md

GitHub Benchmark

The GitHub benchmark harness lives in bench-github/. It runs agent tasks across different interface conditions and grades results with an LLM judge.

pnpm install

# Run a single condition × task
pnpm --dir bench-github run bench -- run --condition axi --task merged_pr_ci_audit --repeat 5 --agent claude

# Run the full matrix
pnpm --dir bench-github run bench -- matrix --repeat 5 --agent claude

# Generate summary report
pnpm --dir bench-github run bench -- report

Published results (425 runs): bench-github/published-results/STUDY.md

Links

• Website
• AXI Skill definition
• Browser benchmark study
• GitHub benchmark study