diff --git a/packages/opencode/test/server/httpapi-listen.test.ts b/packages/opencode/test/server/httpapi-listen.test.ts
index 065e883fff..f155521384 100644
--- a/packages/opencode/test/server/httpapi-listen.test.ts
+++ b/packages/opencode/test/server/httpapi-listen.test.ts
@@ -1,4 +1,5 @@
 import { afterEach, describe, expect, test } from "bun:test"
+import net from "node:net"
 import { Flag } from "@opencode-ai/core/flag/flag"
 import * as Log from "@opencode-ai/core/util/log"
 import { Server } from "../../src/server/server"
@@ -302,6 +303,32 @@ describe("HttpApi Server.listen", () => {
     expect(output).not.toContain("Sent HTTP response")
   })
 
+  test("port 0 prefers 4096 when free", async () => {
+    if (!(await isPortFree(4096))) return
+    const listener = await startListener()
+    try {
+      expect(listener.port).toBe(4096)
+    } finally {
+      await stop(listener, "timed out cleaning up port-0 prefers-4096 listener")
+    }
+  })
+
+  test("port 0 falls back when 4096 is taken", async () => {
+    const blocker = await occupyPort(4096)
+    if (!blocker) return
+    try {
+      const listener = await startListener()
+      try {
+        expect(listener.port).not.toBe(4096)
+        expect(listener.port).toBeGreaterThan(0)
+      } finally {
+        await stop(listener, "timed out cleaning up port-0 fallback listener")
+      }
+    } finally {
+      await new Promise<void>((resolve) => blocker.close(() => resolve()))
+    }
+  })
+
   testPty("rejects unsafe PTY ticket mint and connect requests", async () => {
     await using tmp = await tmpdir({ git: true, config: { formatter: false, lsp: false } })
     const listener = await startListener()
@@ -389,3 +416,20 @@ describe("HttpApi Server.listen", () => {
     }
   })
 })
+
+function isPortFree(port: number) {
+  return new Promise<boolean>((resolve) => {
+    const probe = net.createServer()
+    probe.once("error", () => resolve(false))
+    probe.once("listening", () => probe.close(() => resolve(true)))
+    probe.listen(port, "127.0.0.1")
+  })
+}
+
+function occupyPort(port: number) {
+  return new Promise<net.Server | undefined>((resolve) => {
+    const server = net.createServer()
+    server.once("error", () => resolve(undefined))
+    server.listen(port, "127.0.0.1", () => resolve(server))
+  })
+}
diff --git a/packages/opencode/test/server/httpapi-mdns.test.ts b/packages/opencode/test/server/httpapi-mdns.test.ts
new file mode 100644
index 0000000000..6b88a1f10b
--- /dev/null
+++ b/packages/opencode/test/server/httpapi-mdns.test.ts
@@ -0,0 +1,82 @@
+import { afterEach, describe, expect, mock, test } from "bun:test"
+import { Flag } from "@opencode-ai/core/flag/flag"
+import * as Log from "@opencode-ai/core/util/log"
+import { withTimeout } from "../../src/util/timeout"
+import { resetDatabase } from "../fixture/db"
+import { disposeAllInstances } from "../fixture/fixture"
+
+void Log.init({ print: false })
+
+type Event = { kind: "publish"; port: number; name: string } | { kind: "unpublishAll" } | { kind: "destroy" }
+const events: Event[] = []
+
+void mock.module("bonjour-service", () => ({
+  Bonjour: class {
+    publish(opts: { port: number; name: string }) {
+      events.push({ kind: "publish", port: opts.port, name: opts.name })
+      return { on: () => {} }
+    }
+    unpublishAll() {
+      events.push({ kind: "unpublishAll" })
+    }
+    destroy() {
+      events.push({ kind: "destroy" })
+    }
+  },
+}))
+
+// Import Server AFTER the mock so the MDNS module picks up the stub.
+const { Server } = await import("../../src/server/server")
+
+const original = {
+  OPENCODE_SERVER_PASSWORD: Flag.OPENCODE_SERVER_PASSWORD,
+  OPENCODE_SERVER_USERNAME: Flag.OPENCODE_SERVER_USERNAME,
+}
+
+afterEach(async () => {
+  events.length = 0
+  Flag.OPENCODE_SERVER_PASSWORD = original.OPENCODE_SERVER_PASSWORD
+  Flag.OPENCODE_SERVER_USERNAME = original.OPENCODE_SERVER_USERNAME
+  await disposeAllInstances()
+  await resetDatabase()
+})
+
+describe("HttpApi Server.listen mDNS", () => {
+  test("skips publish for loopback hostnames", async () => {
+    Flag.OPENCODE_SERVER_PASSWORD = "mdns-secret"
+    Flag.OPENCODE_SERVER_USERNAME = "opencode"
+    const listener = await Server.listen({ hostname: "127.0.0.1", port: 0, mdns: true })
+    try {
+      expect(events.filter((e) => e.kind === "publish")).toEqual([])
+    } finally {
+      await withTimeout(listener.stop(true), 10_000, "timed out stopping loopback mdns listener")
+    }
+    expect(events.filter((e) => e.kind === "publish")).toEqual([])
+  })
+
+  test("publishes for non-loopback hostnames and unpublishes on stop", async () => {
+    Flag.OPENCODE_SERVER_PASSWORD = "mdns-secret"
+    Flag.OPENCODE_SERVER_USERNAME = "opencode"
+    const listener = await Server.listen({ hostname: "0.0.0.0", port: 0, mdns: true })
+    try {
+      const published = events.filter((e) => e.kind === "publish")
+      expect(published.length).toBe(1)
+      expect(published[0]!.port).toBe(listener.port)
+      expect(published[0]!.name).toBe(`opencode-${listener.port}`)
+    } finally {
+      await withTimeout(listener.stop(true), 10_000, "timed out stopping mdns listener")
+    }
+    expect(events.some((e) => e.kind === "unpublishAll")).toBe(true)
+    expect(events.some((e) => e.kind === "destroy")).toBe(true)
+  })
+
+  test("scope finalizer unpublishes even if stop() is not called for force-close", async () => {
+    Flag.OPENCODE_SERVER_PASSWORD = "mdns-secret"
+    Flag.OPENCODE_SERVER_USERNAME = "opencode"
+    const listener = await Server.listen({ hostname: "0.0.0.0", port: 0, mdns: true })
+    expect(events.filter((e) => e.kind === "publish").length).toBe(1)
+    // Plain (graceful) stop without close=true should still unpublish.
+    await withTimeout(listener.stop(), 10_000, "timed out stopping graceful mdns listener")
+    expect(events.some((e) => e.kind === "unpublishAll")).toBe(true)
+  })
+})