anthropics/anthropic-sdk-python

Structural Verdict

How Data Flows Through the System

API requests flow through client authentication, resource-specific formatting, HTTP transport via httpx, response parsing through Pydantic models, and optional streaming/tool execution loops.

1. Client Authentication — API key validation and environment setup in Anthropic client constructor
2. Request Formation — Parameters validated against Pydantic schemas and formatted for API endpoints
3. HTTP Transport — Requests sent via httpx with retry logic, error handling, and platform-specific adapters
4. Response Processing — JSON responses parsed into typed Pydantic models with validation
5. Streaming Handling — SSE events processed incrementally with event accumulation and delta management
6. Tool Execution — Tool calls extracted, executed locally, and results fed back to Claude in conversation loop

System Behavior

How the system actually operates at runtime — where data accumulates, what loops, what waits, and what controls what.

Data Pools

Feedback Loops

• Retry Logic (retry, balancing) — Trigger: HTTP errors or rate limits. Action: Exponential backoff with jitter. Exit: Success or max retries reached.
• Tool Runner Loop (recursive, reinforcing) — Trigger: Claude returns tool_use content. Action: Execute tool, append result, send back to Claude. Exit: Claude stops calling tools.
• Streaming Accumulation (convergence, balancing) — Trigger: SSE events from API. Action: Accumulate partial content into complete message. Exit: Stream ends or error.

Delays & Async Processing

• Rate Limiting (rate-limit, ~Variable based on API limits) — Requests queued until rate limit window resets
• Streaming Response (async-processing, ~Real-time as tokens generate) — Progressive content delivery with delta events
• Tool Execution (async-processing, ~Depends on tool implementation) — Conversation paused while tools execute before Claude responds

Control Points

• ANTHROPIC_API_KEY (env-var) — Controls: API authentication endpoint selection
• max_tokens (threshold) — Controls: Response length limit per message
• thinking.budget_tokens (threshold) — Controls: Token allocation for Claude's thinking process
• stream (feature-flag) — Controls: Enable streaming vs batch response mode

Technology Stack

Key Components

• Anthropic (class) — Main synchronous client for Anthropic API with authentication and resource management src/anthropic/_client.py
• Messages (class) — Resource manager for message creation, streaming, and parsing with tool support src/anthropic/resources/messages.py
• MessageStream (class) — Handles streaming message responses with event processing and accumulation src/anthropic/lib/streaming/_messages.py
• beta_tool (function) — Decorator that converts Python functions into Claude-compatible tool definitions src/anthropic/lib/tools/beta_tool.py
• AnthropicBedrock (class) — Client adapter for using Claude through AWS Bedrock with boto3 integration src/anthropic/_bedrock.py
• Message (type-def) — Pydantic model defining the structure of Claude's message responses src/anthropic/types/message.py
• MessageCreateParams (type-def) — Typed parameters for message creation including tools, system prompts, and streaming src/anthropic/types/message_create_params.py
• BetaLocalFilesystemMemoryTool (class) — Tool implementation for persistent conversation memory using local filesystem storage src/anthropic/tools/beta_local_filesystem_memory_tool.py
• ContentBlock (type-def) — Union type for different content types (text, image, tool_use, tool_result) src/anthropic/types/content_block.py
• _parse (function) — Structured output parsing that converts Claude responses to Pydantic models src/anthropic/_parsers.py
• async_mcp_tool (function) — Converts MCP server tools to Anthropic-compatible tool definitions for async usage src/anthropic/lib/tools/mcp.py

Configuration

release-please-config.json (json)

• $schema (string, unknown) — default: https://raw.githubusercontent.com/stainless-api/release-please/main/schemas/config.json
• include-v-in-tag (boolean, unknown) — default: true
• include-component-in-tag (boolean, unknown) — default: false
• versioning (string, unknown) — default: prerelease
• prerelease (boolean, unknown) — default: true
• bump-minor-pre-major (boolean, unknown) — default: true
• bump-patch-for-minor-pre-major (boolean, unknown) — default: false
• pull-request-header (string, unknown) — default: Automated Release PR
• +4 more parameters

src/anthropic/_legacy_response.py (python-pydantic)

• foo (str, unknown)

src/anthropic/_response.py (python-pydantic)

• foo (str, unknown)

src/anthropic/_response.py (python-pydantic)

• foo (str, unknown)

Related Library Repositories

Frequently Asked Questions

Analyzed on March 31, 2026 by CodeSea. Written by Karolina Sarna.