fix: improve plugin system robustness — agent/command resolution, async errors, hook timing, two-phase init (#18280)

Co-authored-by: Aiden Cline <63023139+rekram1-node@users.noreply.github.com>

packages/opencode/test/plugin/auth-override.test.ts

@@ -54,3 +54,19 @@ describe("plugin.auth-override", () => {
     expect(plainMethods[ProviderID.make("github-copilot")][0].label).not.toBe("Test Override Auth")
   }, 30000) // Increased timeout for plugin installation
 })
+
+const file = path.join(import.meta.dir, "../../src/plugin/index.ts")
+
+describe("plugin.config-hook-error-isolation", () => {
+  test("config hooks are individually error-isolated in the layer factory", async () => {
+    const src = await Bun.file(file).text()
+
+    // The config hook try/catch lives in the InstanceState factory (layer definition),
+    // not in init() which now just delegates to the Effect service.
+    expect(src).toContain("plugin config hook failed")
+
+    const pattern =
+      /for\s*\(const hook of hooks\)\s*\{[\s\S]*?try\s*\{[\s\S]*?\.config\?\.\([\s\S]*?\}\s*catch\s*\(err\)\s*\{[\s\S]*?plugin config hook failed[\s\S]*?\}/
+    expect(pattern.test(src)).toBe(true)
+  })
+})

packages/opencode/test/server/session-messages.test.ts

@@ -117,3 +117,16 @@ describe("session messages endpoint", () => {
     })
   })
 })
+
+describe("session.prompt_async error handling", () => {
+  test("prompt_async route has error handler for detached prompt call", async () => {
+    const src = await Bun.file(path.join(import.meta.dir, "../../src/server/routes/session.ts")).text()
+    const start = src.indexOf('"/:sessionID/prompt_async"')
+    const end = src.indexOf('"/:sessionID/command"', start)
+    expect(start).toBeGreaterThan(-1)
+    expect(end).toBeGreaterThan(start)
+    const route = src.slice(start, end)
+    expect(route).toContain(".catch(")
+    expect(route).toContain("Bus.publish(Session.Event.Error")
+  })
+})

packages/opencode/test/session/prompt.test.ts

@@ -1,5 +1,6 @@
 import path from "path"
 import { describe, expect, test } from "bun:test"
+import { NamedError } from "@opencode-ai/util/error"
 import { fileURLToPath } from "url"
 import { Instance } from "../../src/project/instance"
 import { ModelID, ProviderID } from "../../src/provider/schema"
@@ -210,3 +211,78 @@ describe("session.prompt agent variant", () => {
     }
   })
 })
+
+describe("session.agent-resolution", () => {
+  test("unknown agent throws typed error", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const session = await Session.create({})
+        const err = await SessionPrompt.prompt({
+          sessionID: session.id,
+          agent: "nonexistent-agent-xyz",
+          noReply: true,
+          parts: [{ type: "text", text: "hello" }],
+        }).then(
+          () => undefined,
+          (e) => e,
+        )
+        expect(err).toBeDefined()
+        expect(err).not.toBeInstanceOf(TypeError)
+        expect(NamedError.Unknown.isInstance(err)).toBe(true)
+        if (NamedError.Unknown.isInstance(err)) {
+          expect(err.data.message).toContain('Agent not found: "nonexistent-agent-xyz"')
+        }
+      },
+    })
+  }, 30000)
+
+  test("unknown agent error includes available agent names", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const session = await Session.create({})
+        const err = await SessionPrompt.prompt({
+          sessionID: session.id,
+          agent: "nonexistent-agent-xyz",
+          noReply: true,
+          parts: [{ type: "text", text: "hello" }],
+        }).then(
+          () => undefined,
+          (e) => e,
+        )
+        expect(NamedError.Unknown.isInstance(err)).toBe(true)
+        if (NamedError.Unknown.isInstance(err)) {
+          expect(err.data.message).toContain("build")
+        }
+      },
+    })
+  }, 30000)
+
+  test("unknown command throws typed error with available names", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const session = await Session.create({})
+        const err = await SessionPrompt.command({
+          sessionID: session.id,
+          command: "nonexistent-command-xyz",
+          arguments: "",
+        }).then(
+          () => undefined,
+          (e) => e,
+        )
+        expect(err).toBeDefined()
+        expect(err).not.toBeInstanceOf(TypeError)
+        expect(NamedError.Unknown.isInstance(err)).toBe(true)
+        if (NamedError.Unknown.isInstance(err)) {
+          expect(err.data.message).toContain('Command not found: "nonexistent-command-xyz"')
+          expect(err.data.message).toContain("init")
+        }
+      },
+    })
+  }, 30000)
+})