Fix incorrect model ID for Gemma 4 26B (missing a4b suffix)

[marand85]

Description

The current configuration for the Gemma 4 26B model uses an incorrect identifier, which prevents the model from loading correctly unless manually patched.
Problem:
The model ID is currently set to gemma-4-26b-it, but the correct ID required by the backend/API is gemma-4-26b-a4b-it.
Evidence/Fix:
I have verified that manually editing the local configuration file at ~/.cache/opencode/models.json resolves the issue. Current (Incorrect)
Config:
"gemma-4-26b-it": {
"id": "gemma-4-26b-it",
"name": "Gemma 4 26B",
...
}
Required (Corrected) Config:
json
"gemma-4-26b-a4b-it": {
"id": "gemma-4-26b-a4b-it",
"name": "Gemma 4 26B A4B",
...
}

Plugins

No response

OpenCode version

No response

Steps to reproduce

Try to initialize or use the gemma-4-26b-it model.
Observe the failure/error due to the incorrect ID.
Manually update models.json with the a4b suffix.
The model becomes fully functional.
Environment:
Config path: ~/.cache/opencode/models.json
Model family: Gemma 4

Screenshot and/or share link

No response

Operating System

debian on WSL

Terminal

bash

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• Update gemma-4-31b to gemma-4-31b-it that’s the damn correct name #21067: Same root cause — incorrect Gemma 4 model ID in the codebase (missing -it suffix for 31B; this issue reports missing -a4b-it suffix for 26B). Both are WSL/Windows reports of the same class of bug.
• gemma-4-26b and gemma-4-31b opencode interaction issues leading to tool loops/failures #21034: Reports gemma-4-26b interaction issues/tool loops, which may be related to the same incorrect model ID.

If your issue is specifically about the 26B variant's a4b suffix and is distinct from the above, please note that in a comment. Otherwise, consider adding your findings as a comment on #21067 to consolidate.

[BrutchsamaJeanLouis]

there is also issue 16531 that blocks gemma4 support