fix(provider): remove LiteLLM workarounds ported upstream, requires LiteLLM v1.85.0-rc.2+ (#26819)

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/opencode/src/provider/transform.ts

@@ -1134,16 +1134,7 @@ export function options(input: {
   if (input.model.api.id.includes("gpt-5") && !input.model.api.id.includes("gpt-5-chat")) {
     if (!input.model.api.id.includes("gpt-5-pro")) {
       result["reasoningEffort"] = "medium"
-      // Only inject reasoningSummary for providers that support it natively.
-      // @ai-sdk/openai-compatible proxies (e.g. LiteLLM) do not understand this
-      // parameter and return "Unknown parameter: 'reasoningSummary'".
-      if (
-        input.model.api.npm === "@ai-sdk/openai" ||
-        input.model.api.npm === "@ai-sdk/azure" ||
-        input.model.api.npm === "@ai-sdk/github-copilot"
-      ) {
-        result["reasoningSummary"] = "auto"
-      }
+      result["reasoningSummary"] = "auto"
     }
 
     // Only set textVerbosity for non-chat gpt-5.x models

packages/opencode/src/session/llm.ts

@@ -194,23 +194,11 @@ const live: Layer.Layer<
 
       const tools = resolveTools(input)
 
-      // LiteLLM and some Anthropic proxies require the tools parameter to be present
-      // when message history contains tool calls, even if no tools are being used.
-      // Add a dummy tool that is never called to satisfy this validation.
-      // This is enabled for:
-      // 1. Providers with "litellm" in their ID or API ID (auto-detected)
-      // 2. Providers with explicit "litellmProxy: true" option (opt-in for custom gateways)
-      const isLiteLLMProxy =
-        item.options?.["litellmProxy"] === true ||
-        input.model.providerID.toLowerCase().includes("litellm") ||
-        input.model.api.id.toLowerCase().includes("litellm")
-
-      // LiteLLM/Bedrock rejects requests where the message history contains tool
-      // calls but no tools param is present. When there are no active tools (e.g.
-      // during compaction), inject a stub tool to satisfy the validation requirement.
-      // The stub description explicitly tells the model not to call it.
+      // GitHub Copilot may require the tools parameter when message history contains
+      // tool calls but no tools are active (e.g. compaction). Inject a stub tool that
+      // is never meant to be invoked. LiteLLM-backed providers are excluded.
       if (
-        (isLiteLLMProxy || input.model.providerID.includes("github-copilot")) &&
+        input.model.providerID.includes("github-copilot") &&
         Object.keys(tools).length === 0 &&
         hasToolCalls(input.messages)
       ) {
@@ -457,7 +445,7 @@ function resolveTools(input: Pick<StreamInput, "tools" | "agent" | "permission"
 }
 
 // Check if messages contain any tool-call content
-// Used to determine if a dummy tool should be added for LiteLLM proxy compatibility
+// Used to determine if a dummy tool should be added (GitHub Copilot only; see stream()).
 export function hasToolCalls(messages: ModelMessage[]): boolean {
   for (const msg of messages) {
     if (!Array.isArray(msg.content)) continue