fix(tui): handle non-string path.isAbsolute inputs gracefully

packages/opencode/src/cli/cmd/run.ts

@@ -313,7 +313,7 @@ export const RunCommand = effectCmd({
         if (args.attach) return args.dir
 
         try {
-          process.chdir(path.isAbsolute(args.dir) ? args.dir : path.join(root, args.dir))
+          process.chdir(Filesystem.isAbsolutePath(args.dir) ? args.dir : path.join(root, args.dir))
           return process.cwd()
         } catch {
           UI.error("Failed to change directory to " + args.dir)

packages/opencode/src/cli/cmd/tui/plugin/runtime.ts

@@ -235,12 +235,15 @@ function isTheme(value: unknown) {
 }
 
 function resolveRoot(root: string) {
+  if (typeof root !== "string") {
+    return path.resolve(process.cwd(), String(root))
+  }
   if (root.startsWith("file://")) {
     const file = fileURLToPath(root)
     if (root.endsWith("/")) return file
     return path.dirname(file)
   }
-  if (path.isAbsolute(root)) return root
+  if (Filesystem.isAbsolutePath(root)) return root
   return path.resolve(process.cwd(), root)
 }
 

packages/opencode/src/cli/cmd/tui/thread.ts

@@ -72,7 +72,10 @@ async function input(value?: string) {
 
 export function resolveThreadDirectory(project?: string, envPWD = process.env.PWD, cwd = process.cwd()) {
   const root = Filesystem.resolve(envPWD ?? cwd)
-  if (project) return Filesystem.resolve(path.isAbsolute(project) ? project : path.join(root, project))
+  if (project !== undefined && project !== null) {
+    const resolved = Filesystem.isAbsolutePath(project) ? project : path.join(root, String(project))
+    return Filesystem.resolve(resolved)
+  }
   return Filesystem.resolve(cwd)
 }
 

packages/opencode/src/config/variable.ts

@@ -63,6 +63,9 @@ export async function substitute(input: SubstituteInput) {
       filePath = path.join(os.homedir(), filePath.slice(2))
     }
 
+    if (typeof filePath !== "string") {
+      throw new InvalidError({ path: configSource, message: `bad file reference: file path must be a string, got ${typeof filePath}` })
+    }
     const resolvedPath = path.isAbsolute(filePath) ? filePath : path.resolve(configDir, filePath)
     const fileContent = (
       await Filesystem.readText(resolvedPath).catch((error: NodeJS.ErrnoException) => {

packages/opencode/src/util/filesystem.ts

@@ -143,6 +143,11 @@ export function resolve(p: string): string {
   }
 }
 
+export function isAbsolutePath(p: unknown): p is string {
+  if (typeof p !== "string") return false
+  return isAbsolute(p)
+}
+
 export function resolveFilePath(root: string, file: string): string {
   const raw = file.startsWith("file://") ? fileURLToPath(file) : file
   if (isAbsolute(raw)) return raw

packages/opencode/test/cli/tui/thread.test.ts

@@ -3,6 +3,7 @@ import fs from "fs/promises"
 import path from "path"
 import { tmpdir } from "../../fixture/fixture"
 import { resolveThreadDirectory } from "../../../src/cli/cmd/tui/thread"
+import { Filesystem } from "../../../src/util/filesystem"
 
 describe("tui thread", () => {
   async function check(project?: string) {
@@ -26,3 +27,44 @@ describe("tui thread", () => {
     await check(".")
   })
 })
+
+describe("safe path handling", () => {
+  test("isAbsolutePath returns false for numeric input", () => {
+    expect(Filesystem.isAbsolutePath(123 as any)).toBe(false)
+  })
+
+  test("isAbsolutePath returns false for null", () => {
+    expect(Filesystem.isAbsolutePath(null as any)).toBe(false)
+  })
+
+  test("isAbsolutePath returns false for undefined", () => {
+    expect(Filesystem.isAbsolutePath(undefined as any)).toBe(false)
+  })
+
+  test("isAbsolutePath returns false for object", () => {
+    expect(Filesystem.isAbsolutePath({} as any)).toBe(false)
+  })
+
+  test("isAbsolutePath returns true for absolute path strings", () => {
+    const abs = process.platform === "win32" ? "C:\\Users" : "/usr"
+    expect(Filesystem.isAbsolutePath(abs)).toBe(true)
+  })
+
+  test("isAbsolutePath returns false for relative path strings", () => {
+    expect(Filesystem.isAbsolutePath("relative/path")).toBe(false)
+  })
+
+  test("resolveThreadDirectory handles numeric project gracefully", () => {
+    const cwd = process.cwd()
+    const result = resolveThreadDirectory(42 as any, cwd, cwd)
+    expect(typeof result).toBe("string")
+    expect(result.length).toBeGreaterThan(0)
+  })
+
+  test("resolveThreadDirectory handles null project gracefully", () => {
+    const cwd = process.cwd()
+    const result = resolveThreadDirectory(null as any, cwd, cwd)
+    expect(typeof result).toBe("string")
+    expect(result).toBe(Filesystem.resolve(cwd))
+  })
+})