[BUG] Custom provider initialization fails with "fn3 is not a function

[boyan250422-code]

Description

Description

Attempting to use a custom provider configuration results in a TypeError: fn3 is not a function during provider initialization. The custom provider feature appears to be incomplete or has compatibility issues.

Reproduction Steps

1. Add the following to opencode.json:

{
  "provider": {
    "custom": {
      "api": "openai",
      "options": {
        "apiKey": "xxx",
        "baseURL": "http://localhost:8045/v1"
      },
      "models": { ... }
    }
  }
}

2. Run opencode run "hello" --model custom/model-name
3. Error occurs during provider initialization

Error Message

ProviderInitError: ProviderInitError
data: { providerID: "custom" }

TypeError: fn3 is not a function

Environment

• OS: Windows 11
• opencode version: v1.0.150 (also affects v1.0.210)
• oh-my-opencode version: v2.14.0

Root Cause

opencode attempts to dynamically load a custom provider module but cannot find the corresponding create* function. The custom provider functionality is either incomplete or has compatibility issues.

Workaround

Use built-in provider with overridden options:

{
  "provider": {
    "anthropic": {
      "options": {
        "apiKey": "your-api-key",
        "baseURL": "http://localhost:8045/v1"
      }
    }
  },
  "model": "anthropic/claude-sonnet-4-5"
}

Expected Behavior

Custom provider should initialize correctly according to the configuration.

Additional Notes

This workaround works for most use cases but limits flexibility when users truly need custom provider definitions.

Plugins

No response

OpenCode version

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Steps to reproduce

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Screenshot and/or share link

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Operating System

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Terminal

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