Anthropic's official CLI: curl with manners

What it does

ant is Anthropic’s first-party CLI for the Claude Developer Platform. It wraps the API in a resource-based command structure (ant messages create, etc.) and handles the tedious parts: API key management, file uploads with automatic base64 encoding, and multiple output formats including JSON, YAML, and a “pretty” mode. It also supports GJSON transforms for filtering responses without reaching for jq.

The interesting bit

The @file syntax is the quietly useful part. Pass an image with --arg @abe.jpg and the CLI sniffs the filetype, encodes binary data as base64 automatically, and embeds it correctly in JSON payloads. You can override with @file:// or @data:// prefixes if the sniffing guesses wrong. It’s the kind of affordance that makes you wonder why every API CLI doesn’t do this.

Key highlights

• Resource-based commands: ant [resource] <command> pattern, mirroring the API structure
• Multiple output formats: auto, json, yaml, pretty, raw, plus separate error formatting
• Built-in GJSON transforms for response filtering without external tools
• File upload shorthand with automatic encoding detection and explicit overrides
• Debug mode exposes full HTTP request/response details
• Linkable against alternate Go SDK versions for development/testing

Caveats

• The README is almost entirely quickstart and installation; no mention of streaming, batch operations, or advanced features like prompt caching
• 509 stars suggests limited adoption or recent release; unclear maturity relative to community alternatives

Verdict

Worth a look if you’re already hitting the Claude API from scripts and tired of hand-rolling curl with base64-encoded attachments. Probably overkill for one-off queries; probably underpowered if you need complex workflow orchestration. The sweet spot is the “moderately automated” middle.