fix(opencode): preserve tool validation errors in v2 (#6519)

Failed bridge requests discarded the daemon error body before OpenCode could show the validation explanation to the agent. Preserve that message and status while retaining the HTTP fallback.

Co-authored-by: paseo-bot[bot] <266920839+paseo-bot[bot]@users.noreply.github.com>

packages/server/src/server/agent/providers/opencode/bridge.test.ts

@@ -9,6 +9,10 @@ import { afterEach, describe, expect, test, vi } from "vitest";
 
 import { createTestLogger } from "../../../../test-utils/test-logger.js";
 import type { PaseoToolCatalog } from "../../tools/types.js";
+import { createPaseoToolCatalog } from "../../tools/paseo-tools.js";
+import { AgentManager } from "../../agent-manager.js";
+import { AgentStorage } from "../../agent-storage.js";
+import { ProviderSnapshotManager } from "../../provider-snapshot-manager.js";
 import {
   OpenCodeBridge,
   loadOpenCodeBridgePluginArtifact,
@@ -291,7 +295,10 @@ describe("OpenCodeBridge", () => {
       ).resolves.toMatchObject({ content: [{ type: "text", text: "child result" }] });
       await expect(
         tools.get("paseo_echo_context")!.execute({ value: "blocked" }, { sessionID: "disabled" }),
-      ).rejects.toThrow("HTTP 403");
+      ).rejects.toMatchObject({
+        message: "Paseo tools are disabled for this session",
+        status: 403,
+      });
       await dispose();
     } finally {
       release();
@@ -300,6 +307,72 @@ describe("OpenCodeBridge", () => {
     }
   });
 
+  test("v2 plugin preserves create_agent validation errors from the daemon", async () => {
+    const paseoHome = await mkdtemp(path.join(tmpdir(), "paseo-opencode-v2-errors-"));
+    temporaryDirectories.push(paseoHome);
+    const logger = createTestLogger();
+    const providerSnapshotManager = new ProviderSnapshotManager({ logger });
+    const catalog = createPaseoToolCatalog({
+      agentManager: new AgentManager({ logger }),
+      agentStorage: new AgentStorage(paseoHome, logger),
+      providerSnapshotManager,
+      logger,
+    });
+    const bridge = new OpenCodeBridge({ paseoHome, logger });
+    bridge.setManifestCatalog(catalog);
+    await bridge.start();
+    const release = bridge.bindSession({ sessionId: "caller", env: {}, tools: catalog });
+    try {
+      const env = await bridge.decorateV2ServerEnv({});
+      const { plugins } = JSON.parse(env.OPENCODE_CONFIG_CONTENT);
+      const plugin = plugins[0];
+      const module = await import(
+        pathToFileURL(path.join(fileURLToPath(plugin.package), "server.js")).href
+      );
+      const tools = new Map<string, V2TestTool>();
+      const dispose = await module.default.setup({
+        options: plugin.options,
+        tool: {
+          transform: async (transform: (editor: { add(tool: V2TestTool): void }) => void) => {
+            transform({ add: (tool) => tools.set(tool.name, tool) });
+            return { dispose: async () => undefined };
+          },
+        },
+        session: {
+          context: async () => [],
+          get: async () => ({ parentID: "" }),
+          hook: async () => ({ dispose: async () => undefined }),
+        },
+      } satisfies V2TestPluginContext);
+      try {
+        const input = { provider: "codex", title: "Invalid provider", initialPrompt: "Hello" };
+        const response = await fetch(
+          `${plugin.options.baseUrl}/_internal/opencode/sessions/caller/tools/create_agent`,
+          {
+            method: "POST",
+            headers: {
+              Authorization: `Bearer ${plugin.options.token}`,
+              "Content-Type": "application/json",
+            },
+            body: JSON.stringify(input),
+          },
+        );
+        expect(response.status).toBe(500);
+        const payload = await response.json();
+        expect(payload.error).toContain("provider must be provider/model");
+        await expect(
+          tools.get("paseo_create_agent")!.execute(input, { sessionID: "caller" }),
+        ).rejects.toMatchObject({ message: payload.error, status: 500 });
+      } finally {
+        await dispose();
+      }
+    } finally {
+      release();
+      await bridge.close();
+      await providerSnapshotManager.shutdown();
+    }
+  });
+
   test("v2 plugin returns a tool image as OpenCode file content", async () => {
     const paseoHome = await mkdtemp(path.join(tmpdir(), "paseo-opencode-v2-image-"));
     temporaryDirectories.push(paseoHome);

packages/server/src/server/agent/providers/opencode/v2/bridge-plugin.mjs

@@ -13,7 +13,16 @@ export default {
         ...(body === undefined ? {} : { body: JSON.stringify(body) }),
       });
       if (allowMissing && response.status === 404) return null;
-      if (!response.ok) throw new Error(`Paseo tool bridge returned HTTP ${response.status}`);
+      if (!response.ok) {
+        const payload = await response.json().catch(() => null);
+        const message =
+          typeof payload?.error === "string" && payload.error
+            ? payload.error
+            : `Paseo tool bridge returned HTTP ${response.status}`;
+        const error = new Error(message);
+        error.status = response.status;
+        throw error;
+      }
       return response.json();
     }
     async function scope(sessionID) {