fix(core): expose MCP output schemas to code mode (#35502)

packages/core/src/mcp/client.ts

@@ -61,6 +61,7 @@ export interface ToolDefinition {
   readonly name: string
   readonly description: string | undefined
   readonly inputSchema: unknown
+  readonly outputSchema: unknown
 }
 
 export interface PromptDefinition {
@@ -235,6 +236,7 @@ export const connect = Effect.fnUntraced(function* (
             name: tool.name,
             description: tool.description,
             inputSchema: tool.inputSchema,
+            outputSchema: "outputSchema" in tool ? tool.outputSchema : undefined,
           }))
         }),
       prompts: () =>

packages/core/src/mcp/index.ts

@@ -42,6 +42,7 @@ export class Tool extends Schema.Class<Tool>("MCP.Tool")({
   name: Schema.String,
   description: Schema.String.pipe(Schema.optional),
   inputSchema: Schema.Unknown.pipe(Schema.optional),
+  outputSchema: Schema.Unknown.pipe(Schema.optional),
 }) {}
 
 export const ToolResultContent = Schema.Union([
@@ -391,7 +392,13 @@ export const layer = Layer.effect(
     } satisfies MCPClient.ElicitationHandler
 
     const toTool = (server: ServerName, def: MCPClient.ToolDefinition) =>
-      new Tool({ server, name: def.name, description: def.description, inputSchema: def.inputSchema })
+      new Tool({
+        server,
+        name: def.name,
+        description: def.description,
+        inputSchema: def.inputSchema,
+        outputSchema: def.outputSchema,
+      })
 
     const toPrompt = (server: ServerName, def: MCPClient.PromptDefinition) =>
       new Prompt({

packages/core/src/tool/mcp.ts

@@ -45,6 +45,7 @@ export const layer = Layer.effectDiscard(
                 properties: schema.properties ?? {},
                 additionalProperties: false,
               },
+              outputSchema: tool.outputSchema as JsonSchema.JsonSchema | undefined,
               execute: (input, context) =>
                 Effect.gen(function* () {
                   yield* permission.assert({