Feature Parity: Go vs Python SDK

Both SDKs are fully functional and production-ready. This document provides a comprehensive comparison.

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Core API & Session Management

Feature	Python	Go	Notes
Query (one-shot)	✓	✓	Simple one-off requests
Client (interactive)	✓	✓	Full bidirectional communication
Message streaming	✓	✓	Python: async generators, Go: channels
Session resumption	✓	✓	Continue previous conversations
Session forking	✓	✓	Branch from existing sessions
Message history	✓	✓	Access and replay messages
Model selection	✓	✓	Switch between models
Max turns control	✓	✓	Limit conversation length
Session store	✓	✓	Pluggable transcript persistence
Session management	✓	✓	List, rename, tag, delete, fork sessions
Subagent transcripts	✓	✓	List and read subagent messages

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Message Types & Content Blocks

Feature	Python	Go	Notes
User messages	✓	✓	User input handling
Assistant messages	✓	✓	Claude responses
System messages	✓	✓	System notifications
Result messages	✓	✓	Final cost/token info
Text content blocks	✓	✓	Plain text responses
Tool use blocks	✓	✓	Tool invocation requests
Tool result blocks	✓	✓	Tool execution results
Thinking blocks	✓	✓	Extended thinking output
Server tool use blocks	✓	✓	Server-side tool requests
Server tool result blocks	✓	✓	Server-side tool results
Task lifecycle messages	✓	✓	Started, progress, notification
Hook event messages	✓	✓	Hook lifecycle debugging
Mirror error messages	✓	✓	Session store error reporting
Forward-compatible parsing	✓	✓	Unknown types handled gracefully

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Tool Integration & Permissions

Feature	Python	Go	Notes
Tool permissions	✓	✓	Permission callbacks
Permission modes	✓	✓	default, acceptEdits, plan, bypass, auto
Tool filtering	✓	✓	AllowedTools, DisallowedTools
Updated input support	✓	✓	Callbacks can modify tool inputs

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MCP (Model Context Protocol) Support

Feature	Python	Go	Notes
SDK MCP servers	✓	✓	Create tools in-process
External MCP servers	✓	✓	stdio, SSE, HTTP connections
Custom MCP servers	✓	✓	Implement MCPServer interface
MCP factory function	-	✓	Go-exclusive convenience API
Tool annotations	✓	✓	ReadOnly, Destructive, OpenWorld metadata
Typed MCP status	✓	✓	McpServerInfo, McpStatusResponse
Strict MCP config	✓	✓	Ignore default CLI MCP servers

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Hook System

Feature	Python	Go	Notes
Pre-tool hooks	✓	✓	Before tool execution
Post-tool hooks	✓	✓	After tool execution
User prompt hooks	✓	✓	Before user input processing
Regex matching	✓	✓	Filter by tool name pattern
Hook continuation	✓	✓	Control execution flow

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Extended Thinking

Feature	Python	Go	Notes
Extended thinking	✓	✓	Long-form reasoning
Max thinking tokens	✓	✓	Limit thinking output
Thinking blocks	✓	✓	Access reasoning process
Thinking control	✓	✓	Enable/disable/adaptive

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Cost Management

Feature	Python	Go	Notes
Token counting	✓	✓	Input/output token counts
Cost summary	✓	✓	Usage statistics per message
Budget limiting	✓	✓	Max budget in USD
Cost estimation	✓	✓	Predict costs

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When to Use Each SDK

Choose Go SDK When:

• You need concurrent request handling (1M+ goroutines)
• You want strong compile-time type safety
• You need high-performance, low-latency responses
• You want single-binary deployment
• You're building microservices or cloud-native apps

Choose Python SDK When:

• You prefer Python's syntax and ecosystem
• You need rapid prototyping capabilities
• You're working with Jupyter notebooks
• You have an existing Python codebase
• You prefer async/await patterns

Both SDKs use the same control protocol, so migrating code between them is straightforward. They are also interoperable in microservice architectures.

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Compatibility

Both SDKs use the same control protocol and are forward-compatible. Install the Claude Code CLI once and use both SDKs on the same machine.

Go SDK Version	Python SDK Version	Compatible
v0.2.0+	v0.1.0+	✓ Yes
v0.1.0+	v0.1.0+	✓ Yes

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Further reading: Architecture Differences | Migration Guide

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