Bug: OpenAI-compatible provider rejects Ollama's reasoning field, causing infinite spin/hang #21903

Description

When using OpenCode with Ollama or other local OpenAI-compatible endpoints, if the model response includes a field reasoning (as produced by Ollama), the result is an infinite spin on 'Build - ' and high CPU, with no output. OpenCode expects Copilot/OpenAI-specific fields: reasoning_text or reasoning_opaque only, and does not accept the generic reasoning field. As a result, UI never recovers. This is confirmed for Ollama 0.20.4 (gemma4, qwen3.5) on Arch Linux. See reproduction step 5 for actual Ollama response proof.

I've tested with a patched version of OpenCode and it works.

modified   packages/opencode/src/provider/sdk/copilot/chat/openai-compatible-chat-language-model.ts
@@ -757,6 +757,7 @@ const OpenAICompatibleChatResponseSchema = z.object({
         // Copilot-specific reasoning fields
         reasoning_text: z.string().nullish(),
         reasoning_opaque: z.string().nullish(),
+        reasoning: z.string().nullish(),  // Ollama-compatibility
         tool_calls: z
           .array(
             z.object({
@@ -792,6 +793,7 @@ const createOpenAICompatibleChatChunkSchema = <ERROR_SCHEMA extends z.core.$ZodT
               // Copilot-specific reasoning fields
               reasoning_text: z.string().nullish(),
               reasoning_opaque: z.string().nullish(),
+              reasoning: z.string().nullish(),  // Ollama-compatibility
               tool_calls: z
                 .array(
                   z.object({

Plugins

No response

OpenCode version

1.4.3

Steps to reproduce

1. Launch Ollama (0.20.4 or later) with a compatible chat model (e.g., gemma4, qwen3.5)
2. Configure OpenCode to use your local OpenAI-compatible backend: ollama launch opencode
3. Prompt the model (any message)
4. Observe: UI spins/hangs with high CPU, never returns output
5. Inspect Ollama's response JSON, which looks like:

{
  "id": "chatcmpl-123",
  "object": "chat.completion",
  "choices": [{
    "message": {
      "role": "assistant",
      "content": "...",
      "reasoning": "Some chain-of-thought reasoning steps"
    }
  }]
}

6. Confirm OpenCode only parses reasoning_text/reasoning_opaque (see openai-compatible-chat-language-model.ts), not reasoning.
7. Workaround: Patch the Zod schema in OpenCode to accept reasoning: z.string().nullish().

Screenshot and/or share link

No response

Operating System

Linux (Arch)

Terminal

Kitty