Haiku 4.5 Model Support

What: Support for the new Claude Haiku 4.5 model (claude-haiku-4-5-20251001), available across all platforms (direct API, Bedrock, Vertex).

How to use:

# Use Haiku 4.5 as your model
claude --model claude-haiku-4-5-20251001

# Or use model aliases
claude --model haiku45

Details:

• Model identifier: claude-haiku-4-5-20251001
• Display name: "Haiku 4.5"
• Platform mappings configured for firstParty, Bedrock (global.anthropic.claude-haiku-4-5-20251001-v1:0), and Vertex (claude-haiku-4-5@20251001)
• Vertex region environment variable: VERTEX_REGION_CLAUDE_HAIKU_4_5
• Haiku 4.5 used in plan mode when model preference is set to "haiku"
• Evidence: Model detection at IOA() at line 83108, platform mappings at lines 83142-83144, model selection logic at x01() at line 144036 (model identifier "haiku-4-5" completely absent from v2.0.15)