refactor(file): effectify FileService as scoped service

Convert File namespace functions (init, status, read, list, search) to
FileService class extending ServiceMap.Service with Effect.fn methods.
File cache uses lazy initialization via init() matching original
Instance.state semantics. Legacy promise facade preserved.

packages/opencode/src/effect/instances.ts

@@ -7,6 +7,8 @@ import { PermissionService } from "@/permission/service"
 import { FileWatcherService } from "@/file/watcher"
 import { VcsService } from "@/project/vcs"
 import { FileTimeService } from "@/file/time"
+import { FormatService } from "@/format"
+import { FileService } from "@/file"
 import { Instance } from "@/project/instance"
 
 export { InstanceContext } from "./instance-context"
@@ -18,6 +20,8 @@ export type InstanceServices =
   | FileWatcherService
   | VcsService
   | FileTimeService
+  | FormatService
+  | FileService
 
 function lookup(directory: string) {
   const project = Instance.project
@@ -29,6 +33,8 @@ function lookup(directory: string) {
     Layer.fresh(FileWatcherService.layer).pipe(Layer.orDie),
     Layer.fresh(VcsService.layer),
     Layer.fresh(FileTimeService.layer).pipe(Layer.orDie),
+    Layer.fresh(FormatService.layer),
+    Layer.fresh(FileService.layer),
   ).pipe(Layer.provide(ctx))
 }
 

packages/opencode/src/format/index.ts

@@ -9,10 +9,13 @@ import { Config } from "../config/config"
 import { mergeDeep } from "remeda"
 import { Instance } from "../project/instance"
 import { Process } from "../util/process"
+import { InstanceContext } from "@/effect/instance-context"
+import { Effect, Layer, ServiceMap } from "effect"
+import { runPromiseInstance } from "@/effect/runtime"
+
+const log = Log.create({ service: "format" })
 
 export namespace Format {
-  const log = Log.create({ service: "format" })
-
   export const Status = z
     .object({
       name: z.string(),
@@ -24,117 +27,135 @@ export namespace Format {
     })
   export type Status = z.infer<typeof Status>
 
-  const state = Instance.state(async () => {
-    const enabled: Record<string, boolean> = {}
-    const cfg = await Config.get()
-
-    const formatters: Record<string, Formatter.Info> = {}
-    if (cfg.formatter === false) {
-      log.info("all formatters are disabled")
-      return {
-        enabled,
-        formatters,
-      }
-    }
-
-    for (const item of Object.values(Formatter)) {
-      formatters[item.name] = item
-    }
-    for (const [name, item] of Object.entries(cfg.formatter ?? {})) {
-      if (item.disabled) {
-        delete formatters[name]
-        continue
-      }
-      const result: Formatter.Info = mergeDeep(formatters[name] ?? {}, {
-        command: [],
-        extensions: [],
-        ...item,
-      })
-
-      if (result.command.length === 0) continue
-
-      result.enabled = async () => true
-      result.name = name
-      formatters[name] = result
-    }
-
-    return {
-      enabled,
-      formatters,
-    }
-  })
-
-  async function isEnabled(item: Formatter.Info) {
-    const s = await state()
-    let status = s.enabled[item.name]
-    if (status === undefined) {
-      status = await item.enabled()
-      s.enabled[item.name] = status
-    }
-    return status
-  }
-
-  async function getFormatter(ext: string) {
-    const formatters = await state().then((x) => x.formatters)
-    const result = []
-    for (const item of Object.values(formatters)) {
-      log.info("checking", { name: item.name, ext })
-      if (!item.extensions.includes(ext)) continue
-      if (!(await isEnabled(item))) continue
-      log.info("enabled", { name: item.name, ext })
-      result.push(item)
-    }
-    return result
+  export async function init() {
+    return runPromiseInstance(FormatService.use((s) => s.init()))
   }
 
   export async function status() {
-    const s = await state()
-    const result: Status[] = []
-    for (const formatter of Object.values(s.formatters)) {
-      const enabled = await isEnabled(formatter)
-      result.push({
-        name: formatter.name,
-        extensions: formatter.extensions,
-        enabled,
-      })
-    }
-    return result
-  }
-
-  export function init() {
-    log.info("init")
-    Bus.subscribe(File.Event.Edited, async (payload) => {
-      const file = payload.properties.file
-      log.info("formatting", { file })
-      const ext = path.extname(file)
-
-      for (const item of await getFormatter(ext)) {
-        log.info("running", { command: item.command })
-        try {
-          const proc = Process.spawn(
-            item.command.map((x) => x.replace("$FILE", file)),
-            {
-              cwd: Instance.directory,
-              env: { ...process.env, ...item.environment },
-              stdout: "ignore",
-              stderr: "ignore",
-            },
-          )
-          const exit = await proc.exited
-          if (exit !== 0)
-            log.error("failed", {
-              command: item.command,
-              ...item.environment,
-            })
-        } catch (error) {
-          log.error("failed to format file", {
-            error,
-            command: item.command,
-            ...item.environment,
-            file,
-          })
-        }
-      }
-    })
+    return runPromiseInstance(FormatService.use((s) => s.status()))
   }
 }
+
+export namespace FormatService {
+  export interface Service {
+    readonly init: () => Effect.Effect<void>
+    readonly status: () => Effect.Effect<Format.Status[]>
+  }
+}
+
+export class FormatService extends ServiceMap.Service<FormatService, FormatService.Service>()("@opencode/Format") {
+  static readonly layer = Layer.effect(
+    FormatService,
+    Effect.gen(function* () {
+      const instance = yield* InstanceContext
+
+      const enabled: Record<string, boolean> = {}
+      const formatters: Record<string, Formatter.Info> = {}
+
+      const cfg = yield* Effect.promise(() => Config.get())
+
+      if (cfg.formatter !== false) {
+        for (const item of Object.values(Formatter)) {
+          formatters[item.name] = item
+        }
+        for (const [name, item] of Object.entries(cfg.formatter ?? {})) {
+          if (item.disabled) {
+            delete formatters[name]
+            continue
+          }
+          const result = mergeDeep(formatters[name] ?? {}, {
+            command: [],
+            extensions: [],
+            ...item,
+          }) as Formatter.Info
+
+          if (result.command.length === 0) continue
+
+          result.enabled = async () => true
+          result.name = name
+          formatters[name] = result
+        }
+      } else {
+        log.info("all formatters are disabled")
+      }
+
+      async function isEnabled(item: Formatter.Info) {
+        let status = enabled[item.name]
+        if (status === undefined) {
+          status = await item.enabled()
+          enabled[item.name] = status
+        }
+        return status
+      }
+
+      async function getFormatter(ext: string) {
+        const result = []
+        for (const item of Object.values(formatters)) {
+          log.info("checking", { name: item.name, ext })
+          if (!item.extensions.includes(ext)) continue
+          if (!(await isEnabled(item))) continue
+          log.info("enabled", { name: item.name, ext })
+          result.push(item)
+        }
+        return result
+      }
+
+      const unsubscribe = Bus.subscribe(
+        File.Event.Edited,
+        Instance.bind(async (payload) => {
+          const file = payload.properties.file
+          log.info("formatting", { file })
+          const ext = path.extname(file)
+
+          for (const item of await getFormatter(ext)) {
+            log.info("running", { command: item.command })
+            try {
+              const proc = Process.spawn(
+                item.command.map((x) => x.replace("$FILE", file)),
+                {
+                  cwd: instance.directory,
+                  env: { ...process.env, ...item.environment },
+                  stdout: "ignore",
+                  stderr: "ignore",
+                },
+              )
+              const exit = await proc.exited
+              if (exit !== 0)
+                log.error("failed", {
+                  command: item.command,
+                  ...item.environment,
+                })
+            } catch (error) {
+              log.error("failed to format file", {
+                error,
+                command: item.command,
+                ...item.environment,
+                file,
+              })
+            }
+          }
+        }),
+      )
+
+      yield* Effect.addFinalizer(() => Effect.sync(unsubscribe))
+      log.info("init")
+
+      const init = Effect.fn("FormatService.init")(function* () {})
+
+      const status = Effect.fn("FormatService.status")(function* () {
+        const result: Format.Status[] = []
+        for (const formatter of Object.values(formatters)) {
+          const isOn = yield* Effect.promise(() => isEnabled(formatter))
+          result.push({
+            name: formatter.name,
+            extensions: formatter.extensions,
+            enabled: isOn,
+          })
+        }
+        return result
+      })
+
+      return FormatService.of({ init, status })
+    }),
+  )
+}

packages/opencode/src/project/bootstrap.ts

@@ -18,7 +18,7 @@ export async function InstanceBootstrap() {
   Log.Default.info("bootstrapping", { directory: Instance.directory })
   await Plugin.init()
   ShareNext.init()
-  Format.init()
+  await Format.init()
   await LSP.init()
   await runPromiseInstance(FileWatcherService.use((service) => service.init()))
   File.init()

packages/opencode/test/file/index.test.ts

@@ -1,4 +1,5 @@
 import { describe, test, expect } from "bun:test"
+import { $ } from "bun"
 import path from "path"
 import fs from "fs/promises"
 import { File } from "../../src/file"
@@ -391,4 +392,469 @@ describe("file/index Filesystem patterns", () => {
       })
     })
   })
+
+  describe("File.status()", () => {
+    test("detects modified file", async () => {
+      await using tmp = await tmpdir({ git: true })
+      const filepath = path.join(tmp.path, "file.txt")
+      await fs.writeFile(filepath, "original\n", "utf-8")
+      await $`git add .`.cwd(tmp.path).quiet()
+      await $`git commit --no-gpg-sign -m "add file"`.cwd(tmp.path).quiet()
+      await fs.writeFile(filepath, "modified\nextra line\n", "utf-8")
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const result = await File.status()
+          const entry = result.find((f) => f.path === "file.txt")
+          expect(entry).toBeDefined()
+          expect(entry!.status).toBe("modified")
+          expect(entry!.added).toBeGreaterThan(0)
+          expect(entry!.removed).toBeGreaterThan(0)
+        },
+      })
+    })
+
+    test("detects untracked file as added", async () => {
+      await using tmp = await tmpdir({ git: true })
+      await fs.writeFile(path.join(tmp.path, "new.txt"), "line1\nline2\nline3\n", "utf-8")
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const result = await File.status()
+          const entry = result.find((f) => f.path === "new.txt")
+          expect(entry).toBeDefined()
+          expect(entry!.status).toBe("added")
+          expect(entry!.added).toBe(4) // 3 lines + trailing newline splits to 4
+          expect(entry!.removed).toBe(0)
+        },
+      })
+    })
+
+    test("detects deleted file", async () => {
+      await using tmp = await tmpdir({ git: true })
+      const filepath = path.join(tmp.path, "gone.txt")
+      await fs.writeFile(filepath, "content\n", "utf-8")
+      await $`git add .`.cwd(tmp.path).quiet()
+      await $`git commit --no-gpg-sign -m "add file"`.cwd(tmp.path).quiet()
+      await fs.rm(filepath)
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const result = await File.status()
+          // Deleted files appear in both numstat (as "modified") and diff-filter=D (as "deleted")
+          const entries = result.filter((f) => f.path === "gone.txt")
+          expect(entries.some((e) => e.status === "deleted")).toBe(true)
+        },
+      })
+    })
+
+    test("detects mixed changes", async () => {
+      await using tmp = await tmpdir({ git: true })
+      await fs.writeFile(path.join(tmp.path, "keep.txt"), "keep\n", "utf-8")
+      await fs.writeFile(path.join(tmp.path, "remove.txt"), "remove\n", "utf-8")
+      await $`git add .`.cwd(tmp.path).quiet()
+      await $`git commit --no-gpg-sign -m "initial"`.cwd(tmp.path).quiet()
+
+      // Modify one, delete one, add one
+      await fs.writeFile(path.join(tmp.path, "keep.txt"), "changed\n", "utf-8")
+      await fs.rm(path.join(tmp.path, "remove.txt"))
+      await fs.writeFile(path.join(tmp.path, "brand-new.txt"), "hello\n", "utf-8")
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const result = await File.status()
+          expect(result.some((f) => f.path === "keep.txt" && f.status === "modified")).toBe(true)
+          expect(result.some((f) => f.path === "remove.txt" && f.status === "deleted")).toBe(true)
+          expect(result.some((f) => f.path === "brand-new.txt" && f.status === "added")).toBe(true)
+        },
+      })
+    })
+
+    test("returns empty for non-git project", async () => {
+      await using tmp = await tmpdir()
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const result = await File.status()
+          expect(result).toEqual([])
+        },
+      })
+    })
+
+    test("returns empty for clean repo", async () => {
+      await using tmp = await tmpdir({ git: true })
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const result = await File.status()
+          expect(result).toEqual([])
+        },
+      })
+    })
+
+    test("parses binary numstat as 0", async () => {
+      await using tmp = await tmpdir({ git: true })
+      const filepath = path.join(tmp.path, "data.bin")
+      // Write content with null bytes so git treats it as binary
+      const binaryData = Buffer.alloc(256)
+      for (let i = 0; i < 256; i++) binaryData[i] = i
+      await fs.writeFile(filepath, binaryData)
+      await $`git add .`.cwd(tmp.path).quiet()
+      await $`git commit --no-gpg-sign -m "add binary"`.cwd(tmp.path).quiet()
+      // Modify the binary
+      const modified = Buffer.alloc(512)
+      for (let i = 0; i < 512; i++) modified[i] = i % 256
+      await fs.writeFile(filepath, modified)
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const result = await File.status()
+          const entry = result.find((f) => f.path === "data.bin")
+          expect(entry).toBeDefined()
+          expect(entry!.status).toBe("modified")
+          expect(entry!.added).toBe(0)
+          expect(entry!.removed).toBe(0)
+        },
+      })
+    })
+  })
+
+  describe("File.list()", () => {
+    test("returns files and directories with correct shape", async () => {
+      await using tmp = await tmpdir({ git: true })
+      await fs.mkdir(path.join(tmp.path, "subdir"))
+      await fs.writeFile(path.join(tmp.path, "file.txt"), "content", "utf-8")
+      await fs.writeFile(path.join(tmp.path, "subdir", "nested.txt"), "nested", "utf-8")
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const nodes = await File.list()
+          expect(nodes.length).toBeGreaterThanOrEqual(2)
+          for (const node of nodes) {
+            expect(node).toHaveProperty("name")
+            expect(node).toHaveProperty("path")
+            expect(node).toHaveProperty("absolute")
+            expect(node).toHaveProperty("type")
+            expect(node).toHaveProperty("ignored")
+            expect(["file", "directory"]).toContain(node.type)
+          }
+        },
+      })
+    })
+
+    test("sorts directories before files, alphabetical within each", async () => {
+      await using tmp = await tmpdir({ git: true })
+      await fs.mkdir(path.join(tmp.path, "beta"))
+      await fs.mkdir(path.join(tmp.path, "alpha"))
+      await fs.writeFile(path.join(tmp.path, "zz.txt"), "", "utf-8")
+      await fs.writeFile(path.join(tmp.path, "aa.txt"), "", "utf-8")
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const nodes = await File.list()
+          const dirs = nodes.filter((n) => n.type === "directory")
+          const files = nodes.filter((n) => n.type === "file")
+          // Dirs come first
+          const firstFile = nodes.findIndex((n) => n.type === "file")
+          const lastDir = nodes.findLastIndex((n) => n.type === "directory")
+          if (lastDir >= 0 && firstFile >= 0) {
+            expect(lastDir).toBeLessThan(firstFile)
+          }
+          // Alphabetical within dirs
+          expect(dirs.map((d) => d.name)).toEqual(dirs.map((d) => d.name).toSorted())
+          // Alphabetical within files
+          expect(files.map((f) => f.name)).toEqual(files.map((f) => f.name).toSorted())
+        },
+      })
+    })
+
+    test("excludes .git and .DS_Store", async () => {
+      await using tmp = await tmpdir({ git: true })
+      await fs.writeFile(path.join(tmp.path, ".DS_Store"), "", "utf-8")
+      await fs.writeFile(path.join(tmp.path, "visible.txt"), "", "utf-8")
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const nodes = await File.list()
+          const names = nodes.map((n) => n.name)
+          expect(names).not.toContain(".git")
+          expect(names).not.toContain(".DS_Store")
+          expect(names).toContain("visible.txt")
+        },
+      })
+    })
+
+    test("marks gitignored files as ignored", async () => {
+      await using tmp = await tmpdir({ git: true })
+      await fs.writeFile(path.join(tmp.path, ".gitignore"), "*.log\nbuild/\n", "utf-8")
+      await fs.writeFile(path.join(tmp.path, "app.log"), "log data", "utf-8")
+      await fs.writeFile(path.join(tmp.path, "main.ts"), "code", "utf-8")
+      await fs.mkdir(path.join(tmp.path, "build"))
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const nodes = await File.list()
+          const logNode = nodes.find((n) => n.name === "app.log")
+          const tsNode = nodes.find((n) => n.name === "main.ts")
+          const buildNode = nodes.find((n) => n.name === "build")
+          expect(logNode?.ignored).toBe(true)
+          expect(tsNode?.ignored).toBe(false)
+          expect(buildNode?.ignored).toBe(true)
+        },
+      })
+    })
+
+    test("lists subdirectory contents", async () => {
+      await using tmp = await tmpdir({ git: true })
+      await fs.mkdir(path.join(tmp.path, "sub"))
+      await fs.writeFile(path.join(tmp.path, "sub", "a.txt"), "", "utf-8")
+      await fs.writeFile(path.join(tmp.path, "sub", "b.txt"), "", "utf-8")
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const nodes = await File.list("sub")
+          expect(nodes.length).toBe(2)
+          expect(nodes.map((n) => n.name).sort()).toEqual(["a.txt", "b.txt"])
+          // Paths should be relative to project root (normalize for Windows)
+          expect(nodes[0].path.replaceAll("\\", "/").startsWith("sub/")).toBe(true)
+        },
+      })
+    })
+
+    test("throws for paths outside project directory", async () => {
+      await using tmp = await tmpdir({ git: true })
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          await expect(File.list("../outside")).rejects.toThrow("Access denied")
+        },
+      })
+    })
+
+    test("works without git", async () => {
+      await using tmp = await tmpdir()
+      await fs.writeFile(path.join(tmp.path, "file.txt"), "hi", "utf-8")
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const nodes = await File.list()
+          expect(nodes.length).toBeGreaterThanOrEqual(1)
+          // Without git, ignored should be false for all
+          for (const node of nodes) {
+            expect(node.ignored).toBe(false)
+          }
+        },
+      })
+    })
+  })
+
+  describe("File.search()", () => {
+    async function setupSearchableRepo() {
+      const tmp = await tmpdir({ git: true })
+      await fs.writeFile(path.join(tmp.path, "index.ts"), "code", "utf-8")
+      await fs.writeFile(path.join(tmp.path, "utils.ts"), "utils", "utf-8")
+      await fs.writeFile(path.join(tmp.path, "readme.md"), "readme", "utf-8")
+      await fs.mkdir(path.join(tmp.path, "src"))
+      await fs.mkdir(path.join(tmp.path, ".hidden"))
+      await fs.writeFile(path.join(tmp.path, "src", "main.ts"), "main", "utf-8")
+      await fs.writeFile(path.join(tmp.path, ".hidden", "secret.ts"), "secret", "utf-8")
+      return tmp
+    }
+
+    test("empty query returns files", async () => {
+      await using tmp = await setupSearchableRepo()
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          File.init()
+          // Give the background scan time to populate
+          await new Promise((r) => setTimeout(r, 500))
+
+          const result = await File.search({ query: "", type: "file" })
+          expect(result.length).toBeGreaterThan(0)
+        },
+      })
+    })
+
+    test("empty query returns dirs sorted with hidden last", async () => {
+      await using tmp = await setupSearchableRepo()
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          File.init()
+          await new Promise((r) => setTimeout(r, 500))
+
+          const result = await File.search({ query: "", type: "directory" })
+          expect(result.length).toBeGreaterThan(0)
+          // Find first hidden dir index
+          const firstHidden = result.findIndex((d) => d.split("/").some((p) => p.startsWith(".") && p.length > 1))
+          const lastVisible = result.findLastIndex((d) => !d.split("/").some((p) => p.startsWith(".") && p.length > 1))
+          if (firstHidden >= 0 && lastVisible >= 0) {
+            expect(firstHidden).toBeGreaterThan(lastVisible)
+          }
+        },
+      })
+    })
+
+    test("fuzzy matches file names", async () => {
+      await using tmp = await setupSearchableRepo()
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          File.init()
+          await new Promise((r) => setTimeout(r, 500))
+
+          const result = await File.search({ query: "main", type: "file" })
+          expect(result.some((f) => f.includes("main"))).toBe(true)
+        },
+      })
+    })
+
+    test("type filter returns only files", async () => {
+      await using tmp = await setupSearchableRepo()
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          File.init()
+          await new Promise((r) => setTimeout(r, 500))
+
+          const result = await File.search({ query: "", type: "file" })
+          // Files don't end with /
+          for (const f of result) {
+            expect(f.endsWith("/")).toBe(false)
+          }
+        },
+      })
+    })
+
+    test("type filter returns only directories", async () => {
+      await using tmp = await setupSearchableRepo()
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          File.init()
+          await new Promise((r) => setTimeout(r, 500))
+
+          const result = await File.search({ query: "", type: "directory" })
+          // Directories end with /
+          for (const d of result) {
+            expect(d.endsWith("/")).toBe(true)
+          }
+        },
+      })
+    })
+
+    test("respects limit", async () => {
+      await using tmp = await setupSearchableRepo()
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          File.init()
+          await new Promise((r) => setTimeout(r, 500))
+
+          const result = await File.search({ query: "", type: "file", limit: 2 })
+          expect(result.length).toBeLessThanOrEqual(2)
+        },
+      })
+    })
+
+    test("query starting with dot prefers hidden files", async () => {
+      await using tmp = await setupSearchableRepo()
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          File.init()
+          await new Promise((r) => setTimeout(r, 500))
+
+          const result = await File.search({ query: ".hidden", type: "directory" })
+          expect(result.length).toBeGreaterThan(0)
+          expect(result[0]).toContain(".hidden")
+        },
+      })
+    })
+  })
+
+  describe("File.read() - diff/patch", () => {
+    test("returns diff and patch for modified tracked file", async () => {
+      await using tmp = await tmpdir({ git: true })
+      const filepath = path.join(tmp.path, "file.txt")
+      await fs.writeFile(filepath, "original content\n", "utf-8")
+      await $`git add .`.cwd(tmp.path).quiet()
+      await $`git commit --no-gpg-sign -m "add file"`.cwd(tmp.path).quiet()
+      await fs.writeFile(filepath, "modified content\n", "utf-8")
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const result = await File.read("file.txt")
+          expect(result.type).toBe("text")
+          expect(result.content).toBe("modified content")
+          expect(result.diff).toBeDefined()
+          expect(result.diff).toContain("original content")
+          expect(result.diff).toContain("modified content")
+          expect(result.patch).toBeDefined()
+          expect(result.patch!.hunks.length).toBeGreaterThan(0)
+        },
+      })
+    })
+
+    test("returns diff for staged changes", async () => {
+      await using tmp = await tmpdir({ git: true })
+      const filepath = path.join(tmp.path, "staged.txt")
+      await fs.writeFile(filepath, "before\n", "utf-8")
+      await $`git add .`.cwd(tmp.path).quiet()
+      await $`git commit --no-gpg-sign -m "add file"`.cwd(tmp.path).quiet()
+      await fs.writeFile(filepath, "after\n", "utf-8")
+      await $`git add .`.cwd(tmp.path).quiet()
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const result = await File.read("staged.txt")
+          expect(result.diff).toBeDefined()
+          expect(result.patch).toBeDefined()
+        },
+      })
+    })
+
+    test("returns no diff for unmodified file", async () => {
+      await using tmp = await tmpdir({ git: true })
+      const filepath = path.join(tmp.path, "clean.txt")
+      await fs.writeFile(filepath, "unchanged\n", "utf-8")
+      await $`git add .`.cwd(tmp.path).quiet()
+      await $`git commit --no-gpg-sign -m "add file"`.cwd(tmp.path).quiet()
+
+      await Instance.provide({
+        directory: tmp.path,
+        fn: async () => {
+          const result = await File.read("clean.txt")
+          expect(result.type).toBe("text")
+          expect(result.content).toBe("unchanged")
+          expect(result.diff).toBeUndefined()
+          expect(result.patch).toBeUndefined()
+        },
+      })
+    })
+  })
 })

packages/opencode/test/format/format.test.ts

@@ -0,0 +1,64 @@
+import { afterEach, describe, expect, test } from "bun:test"
+import { tmpdir } from "../fixture/fixture"
+import { withServices } from "../fixture/instance"
+import { FormatService } from "../../src/format"
+import { Instance } from "../../src/project/instance"
+
+describe("FormatService", () => {
+  afterEach(() => Instance.disposeAll())
+
+  test("status() returns built-in formatters when no config overrides", async () => {
+    await using tmp = await tmpdir()
+
+    await withServices(tmp.path, FormatService.layer, async (rt) => {
+      const statuses = await rt.runPromise(FormatService.use((s) => s.status()))
+      expect(Array.isArray(statuses)).toBe(true)
+      expect(statuses.length).toBeGreaterThan(0)
+
+      for (const s of statuses) {
+        expect(typeof s.name).toBe("string")
+        expect(Array.isArray(s.extensions)).toBe(true)
+        expect(typeof s.enabled).toBe("boolean")
+      }
+
+      const gofmt = statuses.find((s) => s.name === "gofmt")
+      expect(gofmt).toBeDefined()
+      expect(gofmt!.extensions).toContain(".go")
+    })
+  })
+
+  test("status() returns empty list when formatter is disabled", async () => {
+    await using tmp = await tmpdir({
+      config: { formatter: false },
+    })
+
+    await withServices(tmp.path, FormatService.layer, async (rt) => {
+      const statuses = await rt.runPromise(FormatService.use((s) => s.status()))
+      expect(statuses).toEqual([])
+    })
+  })
+
+  test("status() excludes formatters marked as disabled in config", async () => {
+    await using tmp = await tmpdir({
+      config: {
+        formatter: {
+          gofmt: { disabled: true },
+        },
+      },
+    })
+
+    await withServices(tmp.path, FormatService.layer, async (rt) => {
+      const statuses = await rt.runPromise(FormatService.use((s) => s.status()))
+      const gofmt = statuses.find((s) => s.name === "gofmt")
+      expect(gofmt).toBeUndefined()
+    })
+  })
+
+  test("init() completes without error", async () => {
+    await using tmp = await tmpdir()
+
+    await withServices(tmp.path, FormatService.layer, async (rt) => {
+      await rt.runPromise(FormatService.use((s) => s.init()))
+    })
+  })
+})