diff --git a/packages/opencode/src/cli/cmd/debug/file.ts b/packages/opencode/src/cli/cmd/debug/file.ts
index 0e6ef98c24..750d25942b 100644
--- a/packages/opencode/src/cli/cmd/debug/file.ts
+++ b/packages/opencode/src/cli/cmd/debug/file.ts
@@ -1,10 +1,11 @@
 import { EOL } from "os"
 import { Effect } from "effect"
 import { FileSystem } from "@opencode-ai/core/filesystem"
+import { FSUtil } from "@opencode-ai/core/fs-util"
 import { LocationServiceMap } from "@opencode-ai/core/location-layer"
 import { Location } from "@opencode-ai/core/location"
 import { AbsolutePath, RelativePath } from "@opencode-ai/core/schema"
-import { effectCmd } from "../../effect-cmd"
+import { CliError, effectCmd } from "../../effect-cmd"
 import { cmd } from "../cmd"
 
 const filesystem = <A, E, R>(effect: Effect.Effect<A, E, R>) =>
@@ -13,6 +14,8 @@ const filesystem = <A, E, R>(effect: Effect.Effect<A, E, R>) =>
     Effect.provide(LocationServiceMap.layer),
   )
 
+const fileError = (error: FileSystem.PathError | FSUtil.Error) => new CliError({ message: error.message })
+
 const FileSearchCommand = effectCmd({
   command: "search <query>",
   describe: "search files by query",
@@ -38,7 +41,9 @@ const FileReadCommand = effectCmd({
       description: "File path to read",
     }),
   handler: Effect.fn("Cli.debug.file.read")(function* (args) {
-    const file = yield* filesystem(FileSystem.Service.use((svc) => svc.read({ path: RelativePath.make(args.path) })))
+    const file = yield* filesystem(
+      FileSystem.Service.use((svc) => svc.read({ path: RelativePath.make(args.path) })),
+    ).pipe(Effect.mapError(fileError))
     process.stdout.write(
       JSON.stringify(
         { content: Buffer.from(file.content).toString("base64"), encoding: "base64", mime: file.mime },
@@ -59,7 +64,9 @@ const FileListCommand = effectCmd({
       description: "File path to list",
     }),
   handler: Effect.fn("Cli.debug.file.list")(function* (args) {
-    const files = yield* filesystem(FileSystem.Service.use((svc) => svc.list({ path: RelativePath.make(args.path) })))
+    const files = yield* filesystem(
+      FileSystem.Service.use((svc) => svc.list({ path: RelativePath.make(args.path) })),
+    ).pipe(Effect.mapError(fileError))
     process.stdout.write(JSON.stringify(files, null, 2) + EOL)
   }),
 })
diff --git a/packages/opencode/src/server/routes/instance/httpapi/handlers/file.ts b/packages/opencode/src/server/routes/instance/httpapi/handlers/file.ts
index bacc4b0457..cfc804d0f6 100644
--- a/packages/opencode/src/server/routes/instance/httpapi/handlers/file.ts
+++ b/packages/opencode/src/server/routes/instance/httpapi/handlers/file.ts
@@ -10,6 +10,10 @@ import ignore from "ignore"
 import path from "path"
 import { HttpApiBuilder } from "effect/unstable/httpapi"
 import { InstanceHttpApi } from "../api"
+import { InvalidRequestError } from "../errors"
+
+const invalidRequest = (error: FileSystem.PathError | FSUtil.Error) =>
+  new InvalidRequestError({ message: error.message, kind: error._tag })
 
 export const fileHandlers = HttpApiBuilder.group(InstanceHttpApi, "file", (handlers) =>
   Effect.gen(function* () {
@@ -79,7 +83,9 @@ export const fileHandlers = HttpApiBuilder.group(InstanceHttpApi, "file", (handl
             .readFileString(path.join(location.project.directory, ".ignore"))
             .pipe(Effect.catch(() => Effect.succeed("")))
           if (ignorefile) ignored.add(ignorefile)
-          return (yield* fs.list({ path: RelativePath.make(ctx.query.path) })).map((item) => ({
+          return (yield* fs
+            .list({ path: RelativePath.make(ctx.query.path) })
+            .pipe(Effect.mapError(invalidRequest))).map((item) => ({
             name: path.basename(item.path),
             path: item.path,
             absolute: path.resolve(location.directory, item.path),
@@ -101,6 +107,7 @@ export const fileHandlers = HttpApiBuilder.group(InstanceHttpApi, "file", (handl
       return yield* filesystem(
         FileSystem.Service.use((fs) => fs.read({ path: RelativePath.make(ctx.query.path) })),
       ).pipe(
+        Effect.mapError(invalidRequest),
         Effect.flatMap((item) =>
           Effect.gen(function* () {
             const text = item.content.includes(0)