Claude SDK for Pharo

The Claude SDK for Pharo provides access to the Claude API from Pharo applications. Send messages, stream responses, use tools, upload files, and access the full Claude API surface — all from a live Pharo 12 image.

Install

Load via Metacello:

Metacello new
  baseline: 'ClaudeSDK';
  repository: 'github://punt-labs/anthropic-sdk-pharo:v0.7.0/src';
  load.

Requires Pharo 12 (x86_64 or arm64). No external dependencies beyond Pharo's built-in Zinc HTTP and STONJSON.

Getting started

| client response |
client := ClaudeClient apiKey: 'sk-ant-api03-...'.
response := client sendMessage: (ClaudeMessageRequest new
  model: ClaudeModel sonnet45;
  maxTokens: 1024;
  addUserMessage: 'Write a haiku about Smalltalk.';
  yourself).
Transcript show: response textContent; cr.

API key

ClaudeClient takes the key directly and is storage-agnostic — ClaudeClient apiKey: 'sk-ant-...' — so library code sources the key however it likes. For scripts, examples, and integration tests, ClaudeSDKExampleSupport resolveClient resolves one for you by walking a documented ladder, most-specific first, environment variable before keyring within each tier:

Tier	Environment variable	Keyring service / account
1. Pharo override	ANTHROPIC_PHARO_API_KEY	anthropic / pharo-api-key
2. General	ANTHROPIC_API_KEY	anthropic / api-key

The first slot that yields a non-empty key wins; a present-but-empty environment variable is treated as absent and falls through. The Pharo override lets you point a Pharo image at a different key without disturbing the ANTHROPIC_API_KEY your other tooling uses. The SDK reads only these documented locations — it never inspects key values, guesses your store layout, or searches.

Provision the general key in your OS keyring under the documented identity:

Backend	Command
pass (Linux)	pass insert anthropic/api-key
secret-tool (Linux / GNOME)	secret-tool store --label='Anthropic API Key' service anthropic account api-key
macOS Keychain	security add-generic-password -U -s anthropic -a api-key -w

Never hard-code a key in source.

Streaming

| client request |
client := ClaudeSDKExampleSupport resolveClient.
request := ClaudeMessageRequest new
  model: ClaudeModel sonnet45;
  maxTokens: 512;
  addUserMessage: 'Count to five.';
  yourself.
client streamMessage: request do: [ :event |
  (event at: 'event') = 'content_block_delta' ifTrue: [
    Transcript show: ((event at: 'data') at: 'delta') at: 'text' ] ].

Tool use

| request |
request := ClaudeMessageRequest new
  model: ClaudeModel sonnet45;
  maxTokens: 1024;
  addTool: (ClaudeTool
    name: 'get_weather'
    description: 'Get current weather for a city.'
    inputSchema: (ClaudeToolInputSchema object
      required: #('city')
      properties: { 'city' -> (ClaudeToolInputSchema string description: 'City name') }));
  addUserMessage: 'What is the weather in Paris?';
  yourself.

Server tools (Anthropic-hosted)

"Enable web search and bash (Anthropic runs these — no local execution)"
request addWebSearch; addBash.

Files API

| client meta |
client := ClaudeSDKExampleSupport resolveClient.
meta := client uploadFile: '/path/to/report.pdf' filename: 'report.pdf' mimeType: 'application/pdf'.
Transcript show: 'File ID: ', meta fileId; cr.

MCP connector

request mcpServers: {
  ClaudeMCPServerDefinition name: 'my-server' url: 'https://mcp.example.com/sse' }.
request betas: { ClaudeBetaHeader mcpClient }.

Packages

Package	Contents
Claude-Messaging-Types	Domain hierarchy: messages, content blocks, tools, models
Claude-Messaging-Errors	ClaudeApiError hierarchy keyed on HTTP status
Claude-Messaging-Streaming	SSE decoder + raw TLS socket streaming
Claude-Messaging-Client	ClaudeClient — entry point for all API calls
Claude-Messaging-Tools	Server-side tool definitions (Anthropic-side execution)
Claude-Messaging-Files	Files API — upload, download, list, delete
Claude-Messaging-MCP	MCP connector — request-side server definitions
Claude-Messaging-Skills	Skills API — upload reusable tool packages
Claude-Messaging-Batches	Message Batches API — create, poll, and stream results (ClaudeBatch* types + ClaudeClient extensions)
Claude-Messaging-Examples	Runnable usage examples
PharoKeyring	Cross-platform OS keyring resolver (read-only) for API keys — pass, secret-tool, or macOS Keychain

Development

git clone git@github.com:punt-labs/anthropic-sdk-pharo.git anthropic-sdk-pharo
cd anthropic-sdk-pharo
make setup   # download Pharo 12 + load packages
make start   # start eval server on port 8422
make test    # run test suite
make lint    # zero findings required

See CONTRIBUTING.md and CLAUDE.md.

Specification

Full API specification: claude-sdk-specification.pdf (also available as a GitHub Release asset).

Roadmap

Version increments and planned API surface: see ROADMAP.md.

License

This project is licensed under the MIT License. See the LICENSE file for details.