feat: configurable tool alias map for repairing miscalled tools

[sirus20x6]

Fixes #14087

Summary

LLMs frequently miscall tools — todo_write instead of todowrite, search instead of grep, etc. The existing experimental_repairToolCall handler normalizes case and separators, but common synonyms were not handled, causing the model to loop on invalid tool calls indefinitely.

Before this change:

This PR adds:

• Built-in alias defaults — common synonyms resolved automatically with no config needed:
  • search → grep, find → glob, cat → read
  • run/shell → bash, todo → todowrite, fetch → webfetch
• Configurable experimental.tool_aliases — a Record<string, string> so users can define their own alias → canonical tool name mappings (overrides builtins)

The repair order is now:

1. Lowercase exact match (existing)
2. Strip separators + case-insensitive match (existing)
3. Config alias lookup (new) — checks raw name, lowercased, and normalized
4. Built-in alias defaults (new) — hardcoded common synonyms
5. Fall back to "invalid" (existing)

Example config

{
  "experimental": {
    "tool_aliases": {
      "search": "codesearch",
      "lint": "bash"
    }
  }
}

Files changed

• packages/opencode/src/config/config.ts — added tool_aliases to experimental schema
• packages/opencode/src/session/llm.ts — alias resolution in experimental_repairToolCall

Test plan

• bun run typecheck passes
• bun run build produces binaries
• Manual test: use a model that tends to miscall tools, verify alias resolution in logs

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

I found one potentially related PR:

• fix: improve tool name repair for local/Ollama models #10558: fix: improve tool name repair for local/Ollama models - This PR also addresses tool name repair functionality, specifically for improving how miscalled tool names are handled for local/Ollama models. It appears to be a related but distinct approach to the same underlying problem of handling tool miscalls.

The current PR (#14085) extends this by adding configurable alias mappings and built-in defaults, while #10558 focuses on repair improvements for specific model types.

[sirus20x6]

bump

[Mte90]

@thdxr just a ping if it is possible to move on this one.
I am getting the same problems with various models...

[sirus20x6]

@thdxr just a ping if it is possible to move on this one. I am getting the same problems with various models...

This seriously helps with any model with tool calling issues. It seems like a no brainer to me.

[sirus20x6]

any comments on this?

[Mte90]

@nexxeln any hope for this? it is not possible to create a tool that use the internal opencode AI to have a workaround in the meantime.