- add defensive nil check for tool call Arguments field
- replace nil input with empty object to comply with Anthropic spec
- prevent API errors when GLM models return null input in tool_use blocks
Zhipu AI's GLM series models may return tool_use blocks with null input field,
which causes their API to reject subsequent requests with error:
"ClaudeContentBlockToolResult object has no attribute id"
This fix ensures compatibility by converting nil inputs to empty objects {},
matching the Anthropic Messages API specification while maintaining backward
compatibility with other providers.
Zane Tung
8d97896a0d