refactor(effect): move read tool onto defineEffect

packages/opencode/specs/effect-migration.md

@@ -235,11 +235,27 @@ Once individual tools are effectified, change `Tool.Info` (`tool/tool.ts`) so `i
 2. Update `Tool.define()` factory to work with Effects
 3. Update `SessionPrompt` to `yield*` tool results instead of `await`ing
 
+### Tool migration details
+
+Until the tool interface itself returns `Effect`, use this transitional pattern for migrated tools:
+
+- `Tool.defineEffect(...)` should `yield*` the services the tool depends on and close over them in the returned tool definition.
+- Keep the bridge at the Promise boundary only. Prefer a single `Effect.runPromise(...)` in the temporary `async execute(...)` implementation, and move the inner logic into `Effect.fn(...)` helpers instead of scattering `runPromise` islands through the tool body.
+- If a tool starts requiring new services, wire them into `ToolRegistry.defaultLayer` so production callers resolve the same dependencies as tests.
+
+Tool tests should use the existing Effect helpers in `packages/opencode/test/lib/effect.ts`:
+
+- Use `testEffect(...)` / `it.live(...)` instead of creating fake local wrappers around effectful tools.
+- Yield the real tool export, then initialize it: `const info = yield* ReadTool`, `const tool = yield* Effect.promise(() => info.init())`.
+- Run tests inside a real instance with `provideTmpdirInstance(...)` or `provideInstance(tmpdirScoped(...))` so instance-scoped services resolve exactly as they do in production.
+
+This keeps migrated tool tests aligned with the production service graph today, and makes the eventual `Tool.Info` → `Effect` cleanup mostly mechanical later.
+
 Individual tools, ordered by value:
 
 - [ ] `apply_patch.ts` — HIGH: multi-step orchestration, error accumulation, Bus events
 - [ ] `bash.ts` — HIGH: shell orchestration, quoting, timeout handling, output capture
-- [ ] `read.ts` — HIGH: streaming I/O, readline, binary detection → FileSystem + Stream
+- [x] `read.ts` — HIGH: streaming I/O, readline, binary detection → FileSystem + Stream
 - [ ] `edit.ts` — HIGH: multi-step diff/format/publish pipeline, FileWatcher lock
 - [ ] `grep.ts` — MEDIUM: spawns ripgrep → ChildProcessSpawner, timeout handling
 - [ ] `write.ts` — MEDIUM: permission checks, diagnostics polling, Bus events

packages/opencode/src/filesystem/index.ts

@@ -188,13 +188,23 @@ export namespace AppFileSystem {
 
   export function normalizePath(p: string): string {
     if (process.platform !== "win32") return p
+    const resolved = pathResolve(windowsPath(p))
     try {
-      return realpathSync.native(p)
+      return realpathSync.native(resolved)
     } catch {
-      return p
+      return resolved
     }
   }
 
+  export function normalizePathPattern(p: string): string {
+    if (process.platform !== "win32") return p
+    if (p === "*") return p
+    const match = p.match(/^(.*)[\\/]\*$/)
+    if (!match) return normalizePath(p)
+    const dir = /^[A-Za-z]:$/.test(match[1]) ? match[1] + "\\" : match[1]
+    return join(normalizePath(dir), "*")
+  }
+
   export function resolve(p: string): string {
     const resolved = pathResolve(windowsPath(p))
     try {

packages/opencode/src/tool/external-directory.ts

@@ -1,7 +1,8 @@
 import path from "path"
+import { Effect } from "effect"
 import type { Tool } from "./tool"
 import { Instance } from "../project/instance"
-import { Filesystem } from "@/util/filesystem"
+import { AppFileSystem } from "../filesystem"
 
 type Kind = "file" | "directory"
 
@@ -15,14 +16,14 @@ export async function assertExternalDirectory(ctx: Tool.Context, target?: string
 
   if (options?.bypass) return
 
-  const full = process.platform === "win32" ? Filesystem.normalizePath(target) : target
+  const full = process.platform === "win32" ? AppFileSystem.normalizePath(target) : target
   if (Instance.containsPath(full)) return
 
   const kind = options?.kind ?? "file"
   const dir = kind === "directory" ? full : path.dirname(full)
   const glob =
     process.platform === "win32"
-      ? Filesystem.normalizePathPattern(path.join(dir, "*"))
+      ? AppFileSystem.normalizePathPattern(path.join(dir, "*"))
       : path.join(dir, "*").replaceAll("\\", "/")
 
   await ctx.ask({
@@ -35,3 +36,11 @@ export async function assertExternalDirectory(ctx: Tool.Context, target?: string
     },
   })
 }
+
+export const assertExternalDirectoryEffect = Effect.fn("Tool.assertExternalDirectory")(function* (
+  ctx: Tool.Context,
+  target?: string,
+  options?: Options,
+) {
+  yield* Effect.promise(() => assertExternalDirectory(ctx, target, options))
+})