diff --git a/src/__tests__/perf/fixtures/in-tree/AGENTS.md b/src/__tests__/perf/fixtures/in-tree/AGENTS.md
new file mode 100644
index 000000000..22257f9ad
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/AGENTS.md
@@ -0,0 +1 @@
+# fixture root
diff --git a/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/AGENTS.md b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/AGENTS.md
new file mode 100644
index 000000000..6bc3f0b2c
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/AGENTS.md
@@ -0,0 +1 @@
+# fixture package
diff --git a/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-16.ts b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-16.ts
new file mode 100644
index 000000000..dad26290a
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-16.ts
@@ -0,0 +1 @@
+export const file16 = 16
diff --git a/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-17.ts b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-17.ts
new file mode 100644
index 000000000..01e60135f
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-17.ts
@@ -0,0 +1 @@
+export const file17 = 17
diff --git a/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-18.ts b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-18.ts
new file mode 100644
index 000000000..000ce187b
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-18.ts
@@ -0,0 +1 @@
+export const file18 = 18
diff --git a/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-19.ts b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-19.ts
new file mode 100644
index 000000000..43ebccb94
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-19.ts
@@ -0,0 +1 @@
+export const file19 = 19
diff --git a/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-20.ts b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-20.ts
new file mode 100644
index 000000000..763bfe44f
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/packages/pkg-one/src/file-20.ts
@@ -0,0 +1 @@
+export const file20 = 20
diff --git a/src/__tests__/perf/fixtures/in-tree/src/AGENTS.md b/src/__tests__/perf/fixtures/in-tree/src/AGENTS.md
new file mode 100644
index 000000000..df55bdcda
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/AGENTS.md
@@ -0,0 +1 @@
+# fixture src
diff --git a/src/__tests__/perf/fixtures/in-tree/src/app/file-01.ts b/src/__tests__/perf/fixtures/in-tree/src/app/file-01.ts
new file mode 100644
index 000000000..8a4e4907d
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/app/file-01.ts
@@ -0,0 +1 @@
+export const file01 = 1
diff --git a/src/__tests__/perf/fixtures/in-tree/src/app/file-02.ts b/src/__tests__/perf/fixtures/in-tree/src/app/file-02.ts
new file mode 100644
index 000000000..20ca96c14
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/app/file-02.ts
@@ -0,0 +1 @@
+export const file02 = 2
diff --git a/src/__tests__/perf/fixtures/in-tree/src/app/file-03.ts b/src/__tests__/perf/fixtures/in-tree/src/app/file-03.ts
new file mode 100644
index 000000000..b7a0ab9bd
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/app/file-03.ts
@@ -0,0 +1 @@
+export const file03 = 3
diff --git a/src/__tests__/perf/fixtures/in-tree/src/app/file-04.ts b/src/__tests__/perf/fixtures/in-tree/src/app/file-04.ts
new file mode 100644
index 000000000..5917ea7a4
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/app/file-04.ts
@@ -0,0 +1 @@
+export const file04 = 4
diff --git a/src/__tests__/perf/fixtures/in-tree/src/app/file-05.ts b/src/__tests__/perf/fixtures/in-tree/src/app/file-05.ts
new file mode 100644
index 000000000..7c842b808
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/app/file-05.ts
@@ -0,0 +1 @@
+export const file05 = 5
diff --git a/src/__tests__/perf/fixtures/in-tree/src/app/file-06.ts b/src/__tests__/perf/fixtures/in-tree/src/app/file-06.ts
new file mode 100644
index 000000000..b48d2d1cd
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/app/file-06.ts
@@ -0,0 +1 @@
+export const file06 = 6
diff --git a/src/__tests__/perf/fixtures/in-tree/src/app/file-07.ts b/src/__tests__/perf/fixtures/in-tree/src/app/file-07.ts
new file mode 100644
index 000000000..9de6f660f
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/app/file-07.ts
@@ -0,0 +1 @@
+export const file07 = 7
diff --git a/src/__tests__/perf/fixtures/in-tree/src/app/file-08.ts b/src/__tests__/perf/fixtures/in-tree/src/app/file-08.ts
new file mode 100644
index 000000000..2f24a3912
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/app/file-08.ts
@@ -0,0 +1 @@
+export const file08 = 8
diff --git a/src/__tests__/perf/fixtures/in-tree/src/app/file-09.ts b/src/__tests__/perf/fixtures/in-tree/src/app/file-09.ts
new file mode 100644
index 000000000..2c4cddbd4
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/app/file-09.ts
@@ -0,0 +1 @@
+export const file09 = 9
diff --git a/src/__tests__/perf/fixtures/in-tree/src/app/file-10.ts b/src/__tests__/perf/fixtures/in-tree/src/app/file-10.ts
new file mode 100644
index 000000000..1d329a0dc
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/app/file-10.ts
@@ -0,0 +1 @@
+export const file10 = 10
diff --git a/src/__tests__/perf/fixtures/in-tree/src/lib/file-11.ts b/src/__tests__/perf/fixtures/in-tree/src/lib/file-11.ts
new file mode 100644
index 000000000..eb1a64844
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/lib/file-11.ts
@@ -0,0 +1 @@
+export const file11 = 11
diff --git a/src/__tests__/perf/fixtures/in-tree/src/lib/file-12.ts b/src/__tests__/perf/fixtures/in-tree/src/lib/file-12.ts
new file mode 100644
index 000000000..6dbff13ec
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/lib/file-12.ts
@@ -0,0 +1 @@
+export const file12 = 12
diff --git a/src/__tests__/perf/fixtures/in-tree/src/lib/file-13.ts b/src/__tests__/perf/fixtures/in-tree/src/lib/file-13.ts
new file mode 100644
index 000000000..5a46ab064
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/lib/file-13.ts
@@ -0,0 +1 @@
+export const file13 = 13
diff --git a/src/__tests__/perf/fixtures/in-tree/src/lib/file-14.ts b/src/__tests__/perf/fixtures/in-tree/src/lib/file-14.ts
new file mode 100644
index 000000000..32824f748
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/lib/file-14.ts
@@ -0,0 +1 @@
+export const file14 = 14
diff --git a/src/__tests__/perf/fixtures/in-tree/src/lib/file-15.ts b/src/__tests__/perf/fixtures/in-tree/src/lib/file-15.ts
new file mode 100644
index 000000000..c0d19485f
--- /dev/null
+++ b/src/__tests__/perf/fixtures/in-tree/src/lib/file-15.ts
@@ -0,0 +1 @@
+export const file15 = 15
diff --git a/src/__tests__/perf/plugin-init.test.ts b/src/__tests__/perf/plugin-init.test.ts
new file mode 100644
index 000000000..1450b6557
--- /dev/null
+++ b/src/__tests__/perf/plugin-init.test.ts
@@ -0,0 +1,121 @@
+import { cpSync, mkdirSync, mkdtempSync, rmSync } from "node:fs"
+import { tmpdir } from "node:os"
+import { join } from "node:path"
+
+import type { PluginInput } from "@opencode-ai/plugin"
+import { createOpencodeClient } from "@opencode-ai/sdk"
+import { describe, expect, it } from "bun:test"
+
+type InitMetrics = {
+  coldMs: number
+  warmMs: [number, number]
+  medianMs: number
+}
+
+function getMedian(values: number[]): number {
+  const sorted = [...values].sort((left, right) => left - right)
+  return sorted[Math.floor(sorted.length / 2)] ?? 0
+}
+
+function createPluginInput(directory: string): PluginInput {
+  const client = createOpencodeClient({ directory })
+
+  return {
+    client,
+    project: {
+      id: `perf-${Date.now()}`,
+      worktree: directory,
+      time: { created: Date.now() },
+    },
+    directory,
+    worktree: directory,
+    serverUrl: new URL("http://localhost"),
+    $: Bun.$,
+  }
+}
+
+async function importFreshPluginModule(): Promise<(typeof import("../../index"))["default"]> {
+  const token = `${Date.now()}-${Math.random()}`
+  return (await import(`../../index?perf=${token}`)).default
+}
+
+async function measureInitMetrics(directory: string): Promise<InitMetrics> {
+  const pluginModule = await importFreshPluginModule()
+  const measurements: number[] = []
+
+  for (let index = 0; index < 3; index += 1) {
+    const input = createPluginInput(directory)
+    const start = performance.now()
+    await pluginModule.server(input, {})
+    measurements.push(performance.now() - start)
+  }
+
+  return {
+    coldMs: measurements[0] ?? 0,
+    warmMs: [measurements[1] ?? 0, measurements[2] ?? 0],
+    medianMs: getMedian(measurements),
+  }
+}
+
+async function measureScenario(
+  label: string,
+  populateDirectory: (directory: string) => void,
+): Promise<InitMetrics> {
+  const rootDirectory = mkdtempSync(join(tmpdir(), "perf-d09-"))
+  const projectDirectory = join(rootDirectory, label)
+  const configDirectory = join(rootDirectory, "opencode-config")
+  const previousConfigDirectory = process.env.OPENCODE_CONFIG_DIR
+
+  mkdirSync(configDirectory, { recursive: true })
+  process.env.OPENCODE_CONFIG_DIR = configDirectory
+
+  try {
+    populateDirectory(projectDirectory)
+    return await measureInitMetrics(projectDirectory)
+  } finally {
+    if (previousConfigDirectory === undefined) {
+      delete process.env.OPENCODE_CONFIG_DIR
+    } else {
+      process.env.OPENCODE_CONFIG_DIR = previousConfigDirectory
+    }
+
+    rmSync(rootDirectory, { recursive: true, force: true })
+  }
+}
+
+function logMetrics(label: string, metrics: InitMetrics): void {
+  console.info(
+    `${label}: cold=${metrics.coldMs.toFixed(1)}ms warm=[${metrics.warmMs.map((value) => value.toFixed(1)).join(", ")}] median=${metrics.medianMs.toFixed(1)}ms`,
+  )
+}
+
+describe("plugin init performance", () => {
+  it("stays within the empty project init budget", async () => {
+    // given
+    const metrics = await measureScenario("empty-project", (directory) => {
+      mkdirSync(directory, { recursive: true })
+    })
+
+    // when
+    logMetrics("empty-project", metrics)
+
+    // then
+    // regression budget
+    expect(metrics.medianMs).toBeLessThan(500)
+  })
+
+  it("stays within the in-tree fixture init budget", async () => {
+    // given
+    const fixtureDirectory = new URL("./fixtures/in-tree/", import.meta.url)
+    const metrics = await measureScenario("in-tree-fixture", (directory) => {
+      cpSync(fixtureDirectory, directory, { recursive: true })
+    })
+
+    // when
+    logMetrics("in-tree-fixture", metrics)
+
+    // then
+    // regression budget
+    expect(metrics.medianMs).toBeLessThan(700)
+  })
+})