Reasoning variants ineffective for alibaba provider: catalog npm (@ai-sdk/openai-compatible) drops enableThinking/thinkingBudget

Summary

Reasoning variants (thinking control) do not work for models served by the built-in alibaba provider. Variant options declared in config (enableThinking / thinkingBudget) are silently dropped before reaching the wire, so users cannot disable or budget thinking on Qwen3 models via Alibaba/DashScope-compatible endpoints.

opencode version: 1.18.25 (desktop and CLI behave identically)

Root cause

The models.dev catalog entry for the alibaba provider uses npm: "@ai-sdk/openai-compatible". Meanwhile:

1. opencode bundles @ai-sdk/alibaba (it is in BUNDLED_PROVIDERS) and that SDK supports enableThinking / thinkingBudget provider options, mapped to the wire fields enable_thinking / thinking_budget (verified in the bundled dist and in @ai-sdk/alibaba sources >= 1.0.17).
2. ProviderTransform.reasoningToggle() even has alibaba-specific handling ({ none: { enableThinking: false }, high: { enableThinking: true } }), and reasoningEffort() deliberately returns nothing for @ai-sdk/alibaba — both only reachable when the model's npm actually is @ai-sdk/alibaba.
3. With the catalog npm (@ai-sdk/openai-compatible), ProviderTransform.providerOptions() wraps variant options under the openaiCompatible key, and that SDK's provider-options schema strips everything except its own fields. Result: no enable_thinking, no thinking_budget on the wire. Only reasoningEffort survives, emitted as reasoning_effort, which DashScope-compatible endpoints ignore (and values like xhigh are not standard effort values anyway).

This overlaps with #42876 and #42793 (body-level variant fields being discarded), but the specific failure here is the catalog npm mismatch: the alibaba-specific variant machinery exists but is never engaged because the provider resolves to the generic openai-compatible SDK.

Reproduction

Config (no secrets needed; any DashScope-compatible endpoint with a thinking model works):

{
  "provider": {
    "alibaba": {
      "options": { "baseURL": "<dashscope-compatible endpoint>", "apiKey": "<key>" },
      "models": {
        "qwen3.8-max": {
          "reasoning": true,
          "variants": {
            "none": { "enableThinking": false },
            "xhigh": { "enableThinking": true, "thinkingBudget": 262144 }
          }
        }
      }
    }
  }
}

Log the outgoing HTTP bodies with a local proxy (opencode run -m alibaba/qwen3.8-max --variant none|xhigh "...").

Observed (1.18.25, catalog npm):

Expected / workaround: adding "npm": "@ai-sdk/alibaba" at the provider level engages the bundled SDK:

Suggested fixes

• Point the alibaba catalog models that support thinking controls at the bundled @ai-sdk/alibaba instead of @ai-sdk/openai-compatible (it is already bundled, so no runtime install is needed), or
• Teach the openai-compatible path to pass enable_thinking / thinking_budget through for alibaba-hosted models.

Related: #42876, #42793