# Anthropic Python SDK v1.8.0

Category: model-behavior
Published: 2026-09-22T16:25:23Z
Source: [Anthropic Python SDK releases](https://github.com/anthropics/anthropic-sdk-python/releases/tag/v1.8.0)
Agent usefulness: 82/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-09-22T18:17:19.031Z
Tags: anthropic, sdk, python

## Human Summary
Anthropic Python SDK v1.8.0 introduces support for claude-opus-5-5, inline tool definitions, and MCP tool-list pinning (beta), alongside several bug fixes and documentation updates.

## Agent Summary
Anthropic Python SDK release v1.8.0 adds beta support for claude-opus-5-5, inline tool definitions, and MCP tool-list pinning. Fixes include resolving Python 3.13 streaming exit crashes, unifying evaluated permission enums in Managed Agents events, and ensuring tools() updates apply immediately.

## Body
Anthropic Python SDK v1.8.0 introduces API support for the claude-opus-5-5 model, inline tool definitions, and beta MCP tool-list pinning. It addresses several issues, including a Python 3.13 crash when streams are left open on exit, immediate application of add tools(), sharing an evaluated permission enum across Managed Agents events, and removing reply-only params from compaction requests in tool runners. Client request param transformations were refactored to use the JSON encoder, and documentation updates were added across various API references (Dreams, User Profiles, Managed Agents).

## Recommended actions
- Upgrade anthropic-sdk-python to v1.8.0 to use claude-opus-5-5, inline tool definitions, and MCP tool-list pinning.
- Verify stream-handling logic on Python 3.13 environments to ensure clean application exits.

## Sponsors
No sponsor placement attached.

## Agent-readable Sponsor Surface
Sponsor inventory is available at /api/sponsors.json with useCases, pricing, API/docs URLs, targetAgents, constraints, CTA URL, commercial disclosure fields, sourceOfTruthUrl, constraintsLastVerifiedAt, constraintsRefreshCadence, driftHandlingPolicy, and constraintPolicy.