[Bug]: ollama-native fails turns where a model returns several tool calls at the same function index #6857

Client or integration

Codex CLI

Area

Provider adapter

Summary

ollama-native fails every turn in which an Ollama Cloud model returns more than one tool call in a single frame, if the calls share a function.index. ollama-cloud/mistral-large-4 does this: each call has its own id, but function.index is 0 for all of them. nativeMessageEvents in src/adapters/ollama-native.ts uses the index as the call's identity (index:${index}). The second call therefore matches the first one's key and the stream fails with:

Provider stream error: ollama-native response changed a tool-call id for an existing index

If the two calls have different function names, the same collision throws reused a tool-call index for another function instead.

There is a second guard behind the first one. The generated Codex catalog marks this model supports_parallel_tool_calls: false, so the request carries parallelToolCalls: false. Once the two calls are recognized as distinct, the adapter throws emitted parallel tool calls while parallelToolCalls:false was requested. Either way the turn fails, and the user gets no answer.

Reproduction

1. Route Codex to ollama-cloud/mistral-large-4 through opencodex (dev at 93ed1a40b, also on main / 2.81.0).
2. Ask for something that needs two independent tool calls, for example reading two files.
3. Codex retries 5 times, then fails with the error above.

The raw native stream for that turn (POST https://ollama.com/api/chat, stream: true, with tools) has both calls in one frame:

{"message":{"role":"assistant","content":"","tool_calls":[
  {"id":"PpZ8JqRmm","function":{"index":0,"name":"read_file","arguments":{"path":"/etc/hostname"}}},
  {"id":"DDe4wZqkx","function":{"index":0,"name":"read_file","arguments":{"path":"/etc/os-release"}}}]},"done":false}
{"message":{"role":"assistant","content":""},"done":true,"done_reason":"tool_calls"}

Version

dev at 93ed1a40b (2026-10-10); also present in the installed 2.72.0 and in main 2.81.0.

Operating system

Ubuntu 24.04 (Linux 6.17, aarch64)

Provider and model

Ollama Cloud (ollama-native) / mistral-large-4

Logs or error output

ERROR: Reconnecting... 5/5
ERROR: stream disconnected before completion: Provider stream error: ollama-native response changed a tool-call id for an existing index

Screenshots and supporting files

Not applicable. The frame above is the whole evidence; the linked PR inlines it as a regression fixture.

Redacted configuration

{ "model": "ollama-cloud/mistral-large-4", "supports_parallel_tool_calls": false }

Checks

• I searched existing issues and documentation.
• I removed secrets, tokens, account details, request credentials, and personal data.