fix(mcp): restore legacy SDK compatibility (#39373)

packages/opencode/src/tool/code-mode.ts

@@ -1,5 +1,5 @@
 import * as Tool from "./tool"
-import { type CallToolResult } from "@modelcontextprotocol/client"
+import { CallToolResultSchema, type CallToolResult } from "@modelcontextprotocol/sdk/types.js"
 import { Cause, Effect, Schema } from "effect"
 import { CodeMode, Tool as SandboxTool, toolError } from "@opencode-ai/codemode"
 import { MCP } from "@/mcp"
@@ -145,7 +145,28 @@ const invokeChildTool = Effect.fn("CodeMode.invokeChildTool")(function* (input:
   )
   const result: CallToolResult = yield* Effect.gen(function* () {
     yield* input.ctx.ask({ permission: input.entry.key, metadata: {}, patterns: ["*"], always: ["*"] })
-    return yield* Effect.promise(() => McpCatalog.callTool(input.entry.tool, input.args, input.ctx.abort))
+    // Deliberately mirrors McpCatalog.convertTool's transport call so the MCP service stays free of tool-loop concerns.
+    return yield* Effect.promise(async () => {
+      const raw = await input.entry.tool.client.callTool(
+        { name: input.entry.tool.def.name, arguments: input.args },
+        CallToolResultSchema,
+        {
+          resetTimeoutOnProgress: true,
+          signal: input.ctx.abort,
+          timeout: input.entry.tool.timeout,
+          // The MCP SDK only sends a progress token when this hook is present, enabling timeout resets.
+          onprogress: () => {},
+        },
+      )
+      if (raw.isError)
+        throw new Error(
+          raw.content
+            .flatMap((item) => (item.type === "text" ? [item.text] : []))
+            .filter((text) => text.trim())
+            .join("\n\n") || "MCP tool returned an error",
+        )
+      return raw
+    })
   }).pipe(
     Effect.withSpan("Tool.execute", {
       attributes: {