diff --git a/packages/opencode/src/bus/bus-event.ts b/packages/opencode/src/bus/bus-event.ts
index 7fe13833c8..1d9a31d4a2 100644
--- a/packages/opencode/src/bus/bus-event.ts
+++ b/packages/opencode/src/bus/bus-event.ts
@@ -1,5 +1,5 @@
 import z from "zod"
-import type { ZodType } from "zod"
+import type { ZodObject, ZodRawShape } from "zod"
 import { Log } from "../util/log"
 
 export namespace BusEvent {
@@ -9,7 +9,7 @@ export namespace BusEvent {
 
   const registry = new Map<string, Definition>()
 
-  export function define<Type extends string, Properties extends ZodType>(type: Type, properties: Properties) {
+  export function define<Type extends string, Properties extends ZodObject<ZodRawShape>>(type: Type, properties: Properties) {
     const result = {
       type,
       properties,
diff --git a/packages/opencode/src/bus/global.ts b/packages/opencode/src/bus/global.ts
index 43386dd6b2..dcc7664007 100644
--- a/packages/opencode/src/bus/global.ts
+++ b/packages/opencode/src/bus/global.ts
@@ -4,7 +4,7 @@ export const GlobalBus = new EventEmitter<{
   event: [
     {
       directory?: string
-      payload: any
+      payload: { type: string; properties: Record<string, unknown> }
     },
   ]
 }>()
diff --git a/packages/opencode/src/config/paths.ts b/packages/opencode/src/config/paths.ts
index 396417e9a5..3b3876d2a2 100644
--- a/packages/opencode/src/config/paths.ts
+++ b/packages/opencode/src/config/paths.ts
@@ -1,5 +1,4 @@
 import path from "path"
-import os from "os"
 import z from "zod"
 import { type ParseError as JsoncParseError, parse as parseJsonc, printParseErrorCode } from "jsonc-parser"
 import { NamedError } from "@opencode-ai/util/error"
@@ -109,9 +108,7 @@ export namespace ConfigPaths {
       }
 
       let filePath = token.replace(/^\{file:/, "").replace(/\}$/, "")
-      if (filePath.startsWith("~/")) {
-        filePath = path.join(os.homedir(), filePath.slice(2))
-      }
+      filePath = Filesystem.expandHome(filePath)
 
       const resolvedPath = path.isAbsolute(filePath) ? filePath : path.resolve(configDir, filePath)
       const fileContent = (
diff --git a/packages/opencode/src/control-plane/workspace.ts b/packages/opencode/src/control-plane/workspace.ts
index e5294844b1..b519895b2f 100644
--- a/packages/opencode/src/control-plane/workspace.ts
+++ b/packages/opencode/src/control-plane/workspace.ts
@@ -124,7 +124,7 @@ export namespace Workspace {
       await parseSSE(res.body, stop, (event) => {
         GlobalBus.emit("event", {
           directory: space.id,
-          payload: event,
+          payload: event as { type: string; properties: Record<string, unknown> },
         })
       })
       // Wait 250ms and retry if SSE connection fails
diff --git a/packages/opencode/src/session/instruction.ts b/packages/opencode/src/session/instruction.ts
index 86f73d0fd2..b482d761c9 100644
--- a/packages/opencode/src/session/instruction.ts
+++ b/packages/opencode/src/session/instruction.ts
@@ -95,9 +95,7 @@ export namespace InstructionPrompt {
     if (config.instructions) {
       for (let instruction of config.instructions) {
         if (instruction.startsWith("https://") || instruction.startsWith("http://")) continue
-        if (instruction.startsWith("~/")) {
-          instruction = path.join(os.homedir(), instruction.slice(2))
-        }
+        instruction = Filesystem.expandHome(instruction)
         const matches = path.isAbsolute(instruction)
           ? await Glob.scan(path.basename(instruction), {
               cwd: path.dirname(instruction),
diff --git a/packages/opencode/src/session/prompt.ts b/packages/opencode/src/session/prompt.ts
index bac958ec10..d1c9684402 100644
--- a/packages/opencode/src/session/prompt.ts
+++ b/packages/opencode/src/session/prompt.ts
@@ -203,7 +203,7 @@ export namespace SessionPrompt {
         if (seen.has(name)) return
         seen.add(name)
         const filepath = name.startsWith("~/")
-          ? path.join(os.homedir(), name.slice(2))
+          ? Filesystem.expandHome(name)
           : path.resolve(Instance.worktree, name)
 
         const stats = await fs.stat(filepath).catch(() => undefined)
diff --git a/packages/opencode/src/skill/skill.ts b/packages/opencode/src/skill/skill.ts
index 5339691a01..1ade02e2b5 100644
--- a/packages/opencode/src/skill/skill.ts
+++ b/packages/opencode/src/skill/skill.ts
@@ -1,11 +1,11 @@
-import os from "os"
 import path from "path"
 import { pathToFileURL } from "url"
 import z from "zod"
-import { Effect, Layer, ServiceMap } from "effect"
+import { Effect, Fiber, Layer, ServiceMap } from "effect"
 import { NamedError } from "@opencode-ai/util/error"
 import type { Agent } from "@/agent/agent"
 import { Bus } from "@/bus"
+import { AppFileSystem } from "@/filesystem"
 import { InstanceContext } from "@/effect/instance-context"
 import { runPromiseInstance } from "@/effect/runtime"
 import { Flag } from "@/flag/flag"
@@ -14,7 +14,6 @@ import { PermissionNext } from "@/permission"
 import { Filesystem } from "@/util/filesystem"
 import { Config } from "../config/config"
 import { ConfigMarkdown } from "../config/markdown"
-import { Glob } from "../util/glob"
 import { Log } from "../util/log"
 import { Discovery } from "./discovery"
 
@@ -54,11 +53,6 @@ export namespace Skill {
   type State = {
     skills: Record<string, Info>
     dirs: Set<string>
-    task?: Promise<void>
-  }
-
-  type Cache = State & {
-    ensure: () => Promise<void>
   }
 
   export interface Interface {
@@ -68,153 +62,172 @@ export namespace Skill {
     readonly available: (agent?: Agent.Info) => Effect.Effect<Info[]>
   }
 
-  const add = async (state: State, match: string) => {
-    const md = await ConfigMarkdown.parse(match).catch(async (err) => {
-      const message = ConfigMarkdown.FrontmatterError.isInstance(err)
-        ? err.data.message
-        : `Failed to parse skill ${match}`
-      const { Session } = await import("@/session")
-      Bus.publish(Session.Event.Error, { error: new NamedError.Unknown({ message }).toObject() })
-      log.error("failed to load skill", { skill: match, err })
-      return undefined
-    })
-
-    if (!md) return
-
-    const parsed = Info.pick({ name: true, description: true }).safeParse(md.data)
-    if (!parsed.success) return
-
-    if (state.skills[parsed.data.name]) {
-      log.warn("duplicate skill name", {
-        name: parsed.data.name,
-        existing: state.skills[parsed.data.name].location,
-        duplicate: match,
-      })
-    }
-
-    state.dirs.add(path.dirname(match))
-    state.skills[parsed.data.name] = {
-      name: parsed.data.name,
-      description: parsed.data.description,
-      location: match,
-      content: md.content,
-    }
-  }
-
-  const scan = async (state: State, root: string, pattern: string, opts?: { dot?: boolean; scope?: string }) => {
-    return Glob.scan(pattern, {
-      cwd: root,
-      absolute: true,
-      include: "file",
-      symlink: true,
-      dot: opts?.dot,
-    })
-      .then((matches) => Promise.all(matches.map((match) => add(state, match))))
-      .catch((error) => {
-        if (!opts?.scope) throw error
-        log.error(`failed to scan ${opts.scope} skills`, { dir: root, error })
-      })
-  }
-
-  // TODO: Migrate to Effect
-  const create = (instance: InstanceContext.Shape, discovery: Discovery.Interface): Cache => {
-    const state: State = {
-      skills: {},
-      dirs: new Set<string>(),
-    }
-
-    const load = async () => {
-      if (!Flag.OPENCODE_DISABLE_EXTERNAL_SKILLS) {
-        for (const dir of EXTERNAL_DIRS) {
-          const root = path.join(Global.Path.home, dir)
-          if (!(await Filesystem.isDir(root))) continue
-          await scan(state, root, EXTERNAL_SKILL_PATTERN, { dot: true, scope: "global" })
-        }
-
-        for await (const root of Filesystem.up({
-          targets: EXTERNAL_DIRS,
-          start: instance.directory,
-          stop: instance.project.worktree,
-        })) {
-          await scan(state, root, EXTERNAL_SKILL_PATTERN, { dot: true, scope: "project" })
-        }
-      }
-
-      for (const dir of await Config.directories()) {
-        await scan(state, dir, OPENCODE_SKILL_PATTERN)
-      }
-
-      const cfg = await Config.get()
-      for (const item of cfg.skills?.paths ?? []) {
-        const expanded = item.startsWith("~/") ? path.join(os.homedir(), item.slice(2)) : item
-        const dir = path.isAbsolute(expanded) ? expanded : path.join(instance.directory, expanded)
-        if (!(await Filesystem.isDir(dir))) {
-          log.warn("skill path not found", { path: dir })
-          continue
-        }
-
-        await scan(state, dir, SKILL_PATTERN)
-      }
-
-      for (const url of cfg.skills?.urls ?? []) {
-        for (const dir of await Effect.runPromise(discovery.pull(url))) {
-          state.dirs.add(dir)
-          await scan(state, dir, SKILL_PATTERN)
-        }
-      }
-
-      log.info("init", { count: Object.keys(state.skills).length })
-    }
-
-    const ensure = () => {
-      if (state.task) return state.task
-      state.task = load().catch((err) => {
-        state.task = undefined
-        throw err
-      })
-      return state.task
-    }
-
-    return { ...state, ensure }
-  }
-
   export class Service extends ServiceMap.Service<Service, Interface>()("@opencode/Skill") {}
 
-  export const layer: Layer.Layer<Service, never, InstanceContext | Discovery.Service> = Layer.effect(
-    Service,
-    Effect.gen(function* () {
-      const instance = yield* InstanceContext
-      const discovery = yield* Discovery.Service
-      const state = create(instance, discovery)
+  export const layer: Layer.Layer<Service, never, InstanceContext | Discovery.Service | AppFileSystem.Service> =
+    Layer.effect(
+      Service,
+      Effect.gen(function* () {
+        const instance = yield* InstanceContext
+        const discovery = yield* Discovery.Service
+        const fs = yield* AppFileSystem.Service
 
-      const get = Effect.fn("Skill.get")(function* (name: string) {
-        yield* Effect.promise(() => state.ensure())
-        return state.skills[name]
-      })
+        const state: State = {
+          skills: {},
+          dirs: new Set<string>(),
+        }
 
-      const all = Effect.fn("Skill.all")(function* () {
-        yield* Effect.promise(() => state.ensure())
-        return Object.values(state.skills)
-      })
+        const add = Effect.fn("Skill.add")(function* (match: string) {
+          const md = yield* Effect.tryPromise(() => ConfigMarkdown.parse(match)).pipe(
+            Effect.catch((err) =>
+              Effect.gen(function* () {
+                const message = ConfigMarkdown.FrontmatterError.isInstance(err)
+                  ? err.data.message
+                  : `Failed to parse skill ${match}`
+                const { Session } = yield* Effect.promise(() => import("@/session"))
+                Bus.publish(Session.Event.Error, { error: new NamedError.Unknown({ message }).toObject() })
+                log.error("failed to load skill", { skill: match, err })
+                return undefined
+              }),
+            ),
+          )
 
-      const dirs = Effect.fn("Skill.dirs")(function* () {
-        yield* Effect.promise(() => state.ensure())
-        return Array.from(state.dirs)
-      })
+          if (!md) return
 
-      const available = Effect.fn("Skill.available")(function* (agent?: Agent.Info) {
-        yield* Effect.promise(() => state.ensure())
-        const list = Object.values(state.skills).toSorted((a, b) => a.name.localeCompare(b.name))
-        if (!agent) return list
-        return list.filter((skill) => PermissionNext.evaluate("skill", skill.name, agent.permission).action !== "deny")
-      })
+          const parsed = Info.pick({ name: true, description: true }).safeParse(md.data)
+          if (!parsed.success) return
 
-      return Service.of({ get, all, dirs, available })
-    }),
-  )
+          if (state.skills[parsed.data.name]) {
+            log.warn("duplicate skill name", {
+              name: parsed.data.name,
+              existing: state.skills[parsed.data.name].location,
+              duplicate: match,
+            })
+          }
+
+          state.dirs.add(path.dirname(match))
+          state.skills[parsed.data.name] = {
+            name: parsed.data.name,
+            description: parsed.data.description,
+            location: match,
+            content: md.content,
+          }
+        })
+
+        const scan = Effect.fn("Skill.scan")(function* (
+          root: string,
+          pattern: string,
+          opts?: { dot?: boolean; scope?: string },
+        ) {
+          const matches = yield* fs
+            .glob(pattern, {
+              cwd: root,
+              absolute: true,
+              include: "file",
+              symlink: true,
+              dot: opts?.dot,
+            })
+            .pipe(
+              Effect.catch((error) => {
+                if (!opts?.scope) return Effect.fail(error)
+                return Effect.sync(() => {
+                  log.error(`failed to scan ${opts.scope} skills`, { dir: root, error })
+                  return [] as string[]
+                })
+              }),
+            )
+
+          yield* Effect.forEach(matches, (match) => add(match), { concurrency: "unbounded" })
+        })
+
+        const load = Effect.fn("Skill.load")(function* () {
+          // Phase 1: External dirs (global)
+          if (!Flag.OPENCODE_DISABLE_EXTERNAL_SKILLS) {
+            for (const dir of EXTERNAL_DIRS) {
+              const root = path.join(Global.Path.home, dir)
+              if (!(yield* fs.isDir(root).pipe(Effect.orDie))) continue
+              yield* scan(root, EXTERNAL_SKILL_PATTERN, { dot: true, scope: "global" })
+            }
+
+            // Phase 2: External dirs (project, walk up)
+            const roots = yield* fs
+              .up({
+                targets: EXTERNAL_DIRS,
+                start: instance.directory,
+                stop: instance.project.worktree,
+              })
+              .pipe(Effect.orDie)
+
+            yield* Effect.forEach(
+              roots,
+              (root) => scan(root, EXTERNAL_SKILL_PATTERN, { dot: true, scope: "project" }),
+              { concurrency: "unbounded" },
+            )
+          }
+
+          // Phase 3: Config directories
+          const dirs = yield* Effect.promise(() => Config.directories())
+          yield* Effect.forEach(dirs, (dir) => scan(dir, OPENCODE_SKILL_PATTERN), { concurrency: "unbounded" })
+
+          // Phase 4: Custom paths
+          const cfg = yield* Effect.promise(() => Config.get())
+          for (const item of cfg.skills?.paths ?? []) {
+            const expanded = Filesystem.expandHome(item)
+            const dir = path.isAbsolute(expanded) ? expanded : path.join(instance.directory, expanded)
+            if (!(yield* fs.isDir(dir).pipe(Effect.orDie))) {
+              log.warn("skill path not found", { path: dir })
+              continue
+            }
+
+            yield* scan(dir, SKILL_PATTERN)
+          }
+
+          // Phase 5: Remote URLs
+          for (const url of cfg.skills?.urls ?? []) {
+            const pullDirs = yield* discovery.pull(url)
+            for (const dir of pullDirs) {
+              state.dirs.add(dir)
+              yield* scan(dir, SKILL_PATTERN)
+            }
+          }
+
+          log.info("init", { count: Object.keys(state.skills).length })
+        })
+
+        const loadFiber = yield* load().pipe(
+          Effect.catchCause((cause) => Effect.sync(() => log.error("init failed", { cause }))),
+          Effect.forkScoped,
+        )
+
+        const get = Effect.fn("Skill.get")(function* (name: string) {
+          yield* Fiber.join(loadFiber)
+          return state.skills[name]
+        })
+
+        const all = Effect.fn("Skill.all")(function* () {
+          yield* Fiber.join(loadFiber)
+          return Object.values(state.skills)
+        })
+
+        const dirs = Effect.fn("Skill.dirs")(function* () {
+          yield* Fiber.join(loadFiber)
+          return Array.from(state.dirs)
+        })
+
+        const available = Effect.fn("Skill.available")(function* (agent?: Agent.Info) {
+          yield* Fiber.join(loadFiber)
+          const list = Object.values(state.skills).toSorted((a, b) => a.name.localeCompare(b.name))
+          if (!agent) return list
+          return list.filter((skill) => PermissionNext.evaluate("skill", skill.name, agent.permission).action !== "deny")
+        })
+
+        return Service.of({ get, all, dirs, available })
+      }),
+    )
 
   export const defaultLayer: Layer.Layer<Service, never, InstanceContext> = layer.pipe(
     Layer.provide(Discovery.defaultLayer),
+    Layer.provide(AppFileSystem.defaultLayer),
   )
 
   export async function get(name: string) {
diff --git a/packages/opencode/src/util/filesystem.ts b/packages/opencode/src/util/filesystem.ts
index 37f00c6b9c..833826c7e3 100644
--- a/packages/opencode/src/util/filesystem.ts
+++ b/packages/opencode/src/util/filesystem.ts
@@ -2,6 +2,7 @@ import { chmod, mkdir, readFile, writeFile } from "fs/promises"
 import { createWriteStream, existsSync, statSync } from "fs"
 import { lookup } from "mime-types"
 import { realpathSync } from "fs"
+import os from "os"
 import { dirname, join, relative, resolve as pathResolve } from "path"
 import { Readable } from "stream"
 import { pipeline } from "stream/promises"
@@ -95,6 +96,10 @@ export namespace Filesystem {
     }
   }
 
+  export function expandHome(p: string): string {
+    return p.startsWith("~/") ? join(os.homedir(), p.slice(2)) : p
+  }
+
   export function mimeType(p: string): string {
     return lookup(p) || "application/octet-stream"
   }
diff --git a/packages/opencode/test/file/watcher.test.ts b/packages/opencode/test/file/watcher.test.ts
index 2cd27643e8..6d4c5f402f 100644
--- a/packages/opencode/test/file/watcher.test.ts
+++ b/packages/opencode/test/file/watcher.test.ts
@@ -5,9 +5,9 @@ import path from "path"
 import { Deferred, Effect, Option } from "effect"
 import { tmpdir } from "../fixture/fixture"
 import { watcherConfigLayer, withServices } from "../fixture/instance"
+import { Bus } from "../../src/bus"
 import { FileWatcher } from "../../src/file/watcher"
 import { Instance } from "../../src/project/instance"
-import { GlobalBus } from "../../src/bus/global"
 
 // Native @parcel/watcher bindings aren't reliably available in CI (missing on Linux, flaky on Windows)
 const describeWatcher = FileWatcher.hasNativeBinding() && !process.env.CI ? describe : describe.skip
@@ -16,7 +16,6 @@ const describeWatcher = FileWatcher.hasNativeBinding() && !process.env.CI ? desc
 // Helpers
 // ---------------------------------------------------------------------------
 
-type BusUpdate = { directory?: string; payload: { type: string; properties: WatcherEvent } }
 type WatcherEvent = { file: string; event: "add" | "change" | "unlink" }
 
 /** Run `body` with a live FileWatcher service. */
@@ -36,22 +35,17 @@ function withWatcher<E>(directory: string, body: Effect.Effect<void, E>) {
 function listen(directory: string, check: (evt: WatcherEvent) => boolean, hit: (evt: WatcherEvent) => void) {
   let done = false
 
-  function on(evt: BusUpdate) {
+  const unsub = Bus.subscribe(FileWatcher.Event.Updated, (evt) => {
     if (done) return
-    if (evt.directory !== directory) return
-    if (evt.payload.type !== FileWatcher.Event.Updated.type) return
-    if (!check(evt.payload.properties)) return
-    hit(evt.payload.properties)
-  }
+    if (!check(evt.properties)) return
+    hit(evt.properties)
+  })
 
-  function cleanup() {
+  return () => {
     if (done) return
     done = true
-    GlobalBus.off("event", on)
+    unsub()
   }
-
-  GlobalBus.on("event", on)
-  return cleanup
 }
 
 function wait(directory: string, check: (evt: WatcherEvent) => boolean) {