claudish/ai_docs/GEMINI_NO_CONTENT_FIX.md

Gemini/Grok Empty Content Fix

Problem

Users reported receiving "(no content)" messages before the actual response when using Gemini 2.0 Flash or other reasoning models.

Root Cause: The proxy server was proactively creating an empty text block (content_block_start with type text) immediately after receiving the request, "for protocol compliance". When the first chunk from the model arrived containing reasoning (thinking) or other content, this empty text block was closed without any text being added to it. Claude Code renders this closed empty block as a "(no content)" message.

Solution

Removed the eager initialization of the empty text block. The code now lazily initializes the appropriate block type (text or thinking) based on the content of the first chunk received from the model.

Changes in src/proxy-server.ts

Removed (Commented Out):

// THINKING BLOCK SUPPORT: We still need to send content_block_start IMMEDIATELY
// Protocol requires it right after message_start, before ping
// But we'll close and reopen if reasoning arrives first
textBlockIndex = currentBlockIndex++;
sendSSE("content_block_start", {
  type: "content_block_start",
  index: textBlockIndex,
  content_block: {
    type: "text",
    text: "",
  },
});
textBlockStarted = true;

Logic Flow

1. Start: Send message_start and ping.
2. Wait: Wait for first chunk from OpenRouter.
3. First Chunk:
   • If Reasoning: Start thinking block (index 0).
   • If Content: Start text block (index 0).
   • If Tool Call: Start tool_use block (index 0).

This ensures that no empty blocks are created and closed, preventing the "(no content)" rendering issue.

Verification

• Analyzed code flow for all 3 scenarios (reasoning, content, tool use).
• Verified that textBlockIndex and currentBlockIndex are correctly managed without the eager initialization.
• Verified that existing lazy initialization logic handles the "not started" state correctly.

Date: 2025-11-25 Status: Fixed