OpenCode 2: restore a failed tool call in the host's finished result shape

The fold restore wrote a failed call's result as { result: { error, content },
resultType: "error" }, which is ToolResultPart.make's input, not its output.
OpenCode 2.2 validates the request against the finished schema, so a single
restored failed call made every request fail with "Schema validation failed".
It now writes { type: "error", value: { error, content } }, the shape the host
itself sends for a failed call.

Co-authored-by: Alfonso <alfonso-magic-context@users.noreply.github.com>

Author: ualtinok

packages/plugin/src/v2/fold/restore.ts

@@ -254,13 +254,16 @@ export function restoreRow(
             providerMetadata: (part.executed === true ? sameProvider : reuse)
                 ? metadata(native)
                 : undefined,
+            // A finished tool-result part, in the shape `ToolResultPart.make` returns:
+            // `{ type, value }`. `{ result, resultType }` is make's input, and
+            // OpenCode 2.2's request schema rejects it, failing every request that
+            // carries a restored failed call.
             result:
                 state.status === "error"
-                    ? { error: state.error, content: toolContent }
+                    ? { type: "error", value: { error: state.error, content: toolContent } }
                     : single?.type === "text"
                       ? { type: "text", value: single.text }
                       : { type: "content", value: toolContent },
-            ...(state.status === "error" ? { resultType: "error" } : {}),
         };
         if (part.executed === true) content.push(result);
         else results.push({ role: "tool", content: [result] });

packages/plugin/src/v2/hooks/payload.test.ts

@@ -1,7 +1,7 @@
 /// <reference types="bun-types" />
 
 import { describe, expect, it, spyOn } from "bun:test";
-import { Message } from "@opencode/ai/schema/messages";
+import { Message, ToolResultValue } from "@opencode/ai/schema/messages";
 import { estimateMessageTokens } from "../../hooks/magic-context/final-wire-token-estimate";
 import type { MessageLike } from "../../hooks/magic-context/tag-messages";
 import {
@@ -243,10 +243,12 @@ describe("adaptPayload", () => {
             state: { status: "error", output: JSON.stringify(failure) },
         });
         payload.commit();
-        expect(callsAndResults(context.messages).results[0]).toMatchObject({
-            resultType: "error",
-            result: failure,
-        });
+        const restored = callsAndResults(context.messages).results[0];
+        // A restored failed call must already be in the host's finished shape;
+        // OpenCode 2.2 validates the request against it and refuses otherwise.
+        expect(restored.result).toEqual({ type: "error", value: failure });
+        expect("resultType" in restored).toBe(false);
+        expect(ToolResultValue.is(restored.result)).toBe(true);
     });
 
     it("keeps error drop marker bytes and call pairing", () => {