v2.0.17 Claude Code Release Notes

Oct 15, 2025

Claude's Analysisby Sonnet 4.6

Haiku 4.5 joins the model selector; Sonnet handles planning while Haiku runs execution by default. A new Explore subagent efficiently searches codebases to save context.

Changes

Total Changes (vs Average)

0.5×

Version Type

Patch

Release Focus

Mixed

Day Since Prior Release

Release # This Month

#10 of 20

Bug Fix Ratio

Post-Release Edits

Change Category

Ecosystem Impact

MCP and Plugins/Skills each appeared in 3 of the last 10 releases — often together — but this release steps back entirely to focus on model rollout and core agentic architecture.

Key Themes

2Haiku 4.5 Two-Tier Model Default|1Explore Subagent for Codebase Navigation|2Proxy Support and Traffic Controls

May Help If You've Noticed

Haiku felt too slow for complex reasoning but Sonnet seemed wasteful for simple tasks — the new default splits automatically

Added2 changes

•Added Haiku 4.5 to model selector!
•Introducing the Explore subagent. Powered by Haiku it'll search through your codebase efficiently to save context!

Other4 changes

•Haiku 4.5 automatically uses Sonnet in plan mode, and Haiku for execution (i.e. SonnetPlan by default)
•3P (Bedrock and Vertex) are not automatically upgraded yet. Manual upgrading can be done through setting ANTHROPIC_DEFAULT_HAIKU_MODEL
•OTEL: support HTTP_PROXY and HTTPS_PROXY
•CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC now disables release notes fetching

Other4 changes

•Haiku 4.5 automatically uses Sonnet in plan mode, and Haiku for execution (i.e. SonnetPlan by default)

•3P (Bedrock and Vertex) are not automatically upgraded yet. Manual upgrading can be done through setting ANTHROPIC_DEFAULT_HAIKU_MODEL

•OTEL: support HTTP_PROXY and HTTPS_PROXY

•CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC now disables release notes fetching

v2.0.17 Claude Code Release Notes

Changes in Claude Code v2.0.17

Added2 changes

Other4 changes

v2.0.17 Claude Code Release Notes

Changes in Claude Code v2.0.17

Added2 changes

Other4 changes