Kiro API requires non-empty content on assistant messages, so
CLIProxyAPI injects placeholder text when assistant messages only
contain tool_use blocks (no text). The previous placeholders were
conversational phrases:
- DefaultAssistantContentWithTools: "I'll help you with that."
- DefaultAssistantContent: "I understand."
In agentic sessions with many tool calls, these phrases appeared
dozens of times in conversation history. Opus 4.6 (and likely other
models) picked up on this pattern and started parroting "I'll help
you with that." before every tool call in its actual responses.
Fix: Replace both placeholders with a single dot ".", which
satisfies Kiro's non-empty requirement without giving the model
a phrase to mimic.
Problem:
- PR #186 fixed empty content for assistant messages and history user messages
- But current user message (isLastMessage == true) was not fixed
- When user message contains only tool_result (no text), content becomes empty
- This causes 'Improperly formed request' errors from Kiro API
- Compaction requests from OpenCode commonly have this pattern
Solution:
- Move empty content check BEFORE the isLastMessage branch
- Apply fallback content to ALL user messages, not just history
- Add DefaultUserContentWithToolResults and DefaultUserContent constants
Fixes compaction failures for OpenCode + Quotio + CLIProxyAPIPlus + Kiro stack
Apply code review feedback from gemini-code-assist:
- Move fallback strings to kirocommon package as exported constants
- Update kiro_claude_request.go to use shared constants
- Update kiro_openai_request.go to use shared constants
- Improves maintainability and avoids duplication
