fix(create): resolve user-supplied Dockerfile path from CLI invocation cwd, not project root

src/cli/tui/screens/agent/AddAgentScreen.tsx

@@ -45,7 +45,6 @@ import {
 } from './types';
 import { Box, Text, useInput } from 'ink';
 import Spinner from 'ink-spinner';
-import { basename, resolve } from 'path';
 import React, { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 
 // Helper to get provider display name and env var name from ModelProvider
@@ -1086,12 +1085,14 @@ export function AddAgentScreen({ existingAgentNames, onComplete, onExit }: AddAg
         {byoStep === 'dockerfile' && (
           <PathInput
             placeholder="Select a Dockerfile"
-            basePath={resolve(project?.projectRoot ?? process.cwd(), byoConfig.codeLocation)}
+            basePath={process.cwd()}
             pathType="file"
             allowEmpty
             emptyHelpText="Press Enter to use the default Dockerfile"
             onSubmit={value => {
-              setByoConfig(c => ({ ...c, dockerfile: value ? basename(value) : '' }));
+              // Preserve the user-entered path; resolution + copy into the
+              // agent code directory happens later in useAddAgent.handleByoPath.
+              setByoConfig(c => ({ ...c, dockerfile: value || '' }));
               goToNextByoStep('dockerfile');
             }}
             onCancel={handleByoBack}

src/cli/tui/screens/agent/__tests__/useAddAgent.test.ts

@@ -0,0 +1,107 @@
+import { resolveUserDockerfile } from '../useAddAgent';
+import { resolve } from 'path';
+import { describe, expect, it, vi } from 'vitest';
+
+// ---------------------------------------------------------------------------
+// resolveUserDockerfile — regression tests for issue #1128
+//
+// The CLI must resolve a user-supplied Dockerfile path relative to the
+// directory the user invoked the CLI from (cwd), NOT relative to the
+// project root or codeLocation. Bare filenames are passed through
+// unchanged so the rendered template default keeps working.
+// ---------------------------------------------------------------------------
+
+describe('resolveUserDockerfile', () => {
+  it('returns copy:false for undefined', () => {
+    const result = resolveUserDockerfile(undefined, '/some/cwd');
+    expect(result).toEqual({ ok: true, copy: false, filename: undefined });
+  });
+
+  it('returns copy:false for empty string', () => {
+    const result = resolveUserDockerfile('', '/some/cwd');
+    expect(result).toEqual({ ok: true, copy: false, filename: undefined });
+  });
+
+  it('returns copy:false for a bare filename and preserves the name', () => {
+    // A bare filename is the schema-valid value persisted in the project spec.
+    // We must not try to copy it; we must keep it as-is.
+    const fileExists = vi.fn(() => false);
+    const result = resolveUserDockerfile('Dockerfile', '/some/cwd', fileExists);
+    expect(result).toEqual({ ok: true, copy: false, filename: 'Dockerfile' });
+    // Importantly: existsSync is NOT consulted for a bare filename, so a
+    // user-supplied "Dockerfile" never gets a misleading "not found" error.
+    expect(fileExists).not.toHaveBeenCalled();
+  });
+
+  it('resolves a relative path against cwd (not project root)', () => {
+    const fileExists = vi.fn(() => true);
+    const cwd = '/home/user/.github';
+    const result = resolveUserDockerfile('./Dockerfile.dev', cwd, fileExists);
+
+    expect(result).toEqual({
+      ok: true,
+      copy: true,
+      sourcePath: resolve(cwd, './Dockerfile.dev'),
+      filename: 'Dockerfile.dev',
+    });
+    expect(fileExists).toHaveBeenCalledWith(resolve(cwd, './Dockerfile.dev'));
+  });
+
+  it('resolves a nested relative path against cwd', () => {
+    const fileExists = vi.fn(() => true);
+    const cwd = '/home/user/.github';
+    const result = resolveUserDockerfile('subdir/Dockerfile.gpu', cwd, fileExists);
+
+    expect(result).toEqual({
+      ok: true,
+      copy: true,
+      sourcePath: resolve(cwd, 'subdir/Dockerfile.gpu'),
+      filename: 'Dockerfile.gpu',
+    });
+  });
+
+  it('honors absolute paths regardless of cwd', () => {
+    const fileExists = vi.fn(() => true);
+    const result = resolveUserDockerfile('/tmp/MyDockerfile', '/home/user', fileExists);
+
+    expect(result).toEqual({
+      ok: true,
+      copy: true,
+      sourcePath: resolve('/tmp/MyDockerfile'),
+      filename: 'MyDockerfile',
+    });
+  });
+
+  it('returns ok:false with a cwd-resolved path when source file is missing', () => {
+    const fileExists = vi.fn(() => false);
+    const cwd = '/home/user/.github';
+    const result = resolveUserDockerfile('./missing.Dockerfile', cwd, fileExists);
+
+    expect(result.ok).toBe(false);
+    if (!result.ok) {
+      // Error message must point at the cwd-resolved path so users can see
+      // the actual filesystem location that was checked.
+      expect(result.error).toContain(resolve(cwd, './missing.Dockerfile'));
+      expect(result.error).toMatch(/Dockerfile not found at/);
+    }
+  });
+
+  it('does not resolve relative to projectRoot/codeLocation (regression for #1128)', () => {
+    // The reporter's scenario: cwd is a sub-directory like ".github", but
+    // the project root and BYO codeLocation are different. The resolver
+    // must use cwd, not <projectRoot>/<codeLocation>.
+    const cwd = '/workspace/proj/.github';
+    const projectRoot = '/workspace/proj';
+    const codeLocation = 'harnesses/';
+
+    const fileExists = vi.fn((p: string) => p === resolve(cwd, './my.Dockerfile'));
+
+    const result = resolveUserDockerfile('./my.Dockerfile', cwd, fileExists);
+
+    expect(result.ok).toBe(true);
+    if (result.ok && result.copy) {
+      expect(result.sourcePath).toBe(resolve(cwd, './my.Dockerfile'));
+      expect(result.sourcePath).not.toBe(resolve(projectRoot, codeLocation, './my.Dockerfile'));
+    }
+  });
+});

src/cli/tui/screens/agent/useAddAgent.ts

@@ -135,6 +135,62 @@ function mapAddAgentConfigToGenerateConfig(config: AddAgentConfig): GenerateConf
   };
 }
 
+// ─────────────────────────────────────────────────────────────────────────────
+// Dockerfile path helpers
+// ─────────────────────────────────────────────────────────────────────────────
+
+/**
+ * Result of resolving a user-supplied Dockerfile path.
+ *
+ * - `ok: true, copy: true`  → the user supplied a path; caller must copy
+ *   `sourcePath` into the destination dir under name `filename`.
+ * - `ok: true, copy: false` → user supplied a bare filename or nothing;
+ *   no copy is needed.
+ * - `ok: false`             → file does not exist at the resolved path.
+ */
+export type ResolveDockerfileResult =
+  | { ok: true; copy: false; filename: string | undefined }
+  | { ok: true; copy: true; sourcePath: string; filename: string }
+  | { ok: false; error: string };
+
+/**
+ * Resolve a user-supplied Dockerfile value relative to `cwd` (the directory
+ * the user invoked the CLI from).
+ *
+ * Behaviour:
+ *  - undefined / empty → no-op (`copy: false`, filename stays undefined).
+ *  - bare filename (e.g. `Dockerfile`) → no-op; the filename is preserved
+ *    as-is for the project spec.
+ *  - anything else (e.g. `./Dockerfile.dev`, `subdir/X`, `/abs/X`, `C:\X`) →
+ *    instruct the caller to copy from `resolve(cwd, value)` into the
+ *    destination directory, persisting only the basename.
+ *
+ * Validates that the resolved source file exists; returns `ok: false` with
+ * a descriptive error otherwise.
+ *
+ * Exported for unit testing — see issue #1128.
+ */
+export function resolveUserDockerfile(
+  value: string | undefined,
+  cwd: string,
+  fileExists: (p: string) => boolean = existsSync
+): ResolveDockerfileResult {
+  if (!value) {
+    return { ok: true, copy: false, filename: undefined };
+  }
+
+  // Bare filename → preserve as-is, no copy.
+  if (value === basename(value)) {
+    return { ok: true, copy: false, filename: value };
+  }
+
+  const sourcePath = resolve(cwd, value);
+  if (!fileExists(sourcePath)) {
+    return { ok: false, error: `Dockerfile not found at ${sourcePath}` };
+  }
+  return { ok: true, copy: true, sourcePath, filename: basename(sourcePath) };
+}
+
 // ─────────────────────────────────────────────────────────────────────────────
 // Hook
 // ─────────────────────────────────────────────────────────────────────────────
@@ -260,15 +316,17 @@ async function handleCreatePath(
   const renderer = createRenderer(renderConfig);
   await renderer.render({ outputDir: projectRoot });
 
-  // If dockerfile is a path (contains /), copy it into the agent directory (overwriting template default)
-  if (generateConfig.dockerfile?.includes('/')) {
-    const sourcePath = resolve(projectRoot, generateConfig.dockerfile);
-    if (!existsSync(sourcePath)) {
-      return { ok: false, error: `Dockerfile not found at ${sourcePath}` };
-    }
-    const filename = basename(sourcePath);
-    copyFileSync(sourcePath, join(agentPath, filename));
-    generateConfig.dockerfile = filename;
+  // If dockerfile is a path (not a bare filename), resolve it relative to the
+  // directory the user invoked the CLI from (process.cwd()), copy it into the
+  // agent directory, and persist only the basename in the project spec
+  // (agent-env schema requires a filename, not a path).
+  const dockerfileResolution = resolveUserDockerfile(generateConfig.dockerfile, process.cwd());
+  if (!dockerfileResolution.ok) {
+    return { ok: false, error: dockerfileResolution.error };
+  }
+  if (dockerfileResolution.copy) {
+    copyFileSync(dockerfileResolution.sourcePath, join(agentPath, dockerfileResolution.filename));
+    generateConfig.dockerfile = dockerfileResolution.filename;
   }
 
   // Write agent to project config
@@ -369,15 +427,17 @@ async function handleByoPath(
   const codeDir = join(projectRoot, config.codeLocation.replace(/\/$/, ''));
   mkdirSync(codeDir, { recursive: true });
 
-  // If dockerfile is a path (contains /), copy it into the code directory and use the filename
+  // If dockerfile is a path (not a bare filename), resolve it relative to the
+  // directory the user invoked the CLI from (process.cwd()), copy it into the
+  // BYO code directory, and use only the basename when persisting.
   let dockerfileName = config.dockerfile;
-  if (dockerfileName?.includes('/')) {
-    const sourcePath = resolve(projectRoot, dockerfileName);
-    if (!existsSync(sourcePath)) {
-      return { ok: false, error: `Dockerfile not found at ${sourcePath}` };
-    }
-    dockerfileName = basename(sourcePath);
-    copyFileSync(sourcePath, join(codeDir, dockerfileName));
+  const byoDockerfileResolution = resolveUserDockerfile(dockerfileName, process.cwd());
+  if (!byoDockerfileResolution.ok) {
+    return { ok: false, error: byoDockerfileResolution.error };
+  }
+  if (byoDockerfileResolution.copy) {
+    copyFileSync(byoDockerfileResolution.sourcePath, join(codeDir, byoDockerfileResolution.filename));
+    dockerfileName = byoDockerfileResolution.filename;
   }
 
   const project = await configIO.readProjectSpec();

src/cli/tui/screens/generate/GenerateWizardUI.tsx

@@ -36,7 +36,6 @@ import {
 } from './types';
 import type { useGenerateWizard } from './useGenerateWizard';
 import { Box, Text, useInput } from 'ink';
-import { basename } from 'path';
 
 // Helper to get provider display name and env var name from ModelProvider
 function getProviderInfo(provider: ModelProvider): { name: string; envVarName: string } {
@@ -234,7 +233,11 @@ export function GenerateWizardUI({
           allowEmpty
           emptyHelpText="Press Enter to use the default Dockerfile"
           onSubmit={value => {
-            wizard.setDockerfile(value ? basename(value) : undefined);
+            // Pass the user-entered path through unchanged. Final basename
+            // resolution + copy into the agent directory happens in
+            // useAddAgent.handleCreatePath, so the directory component must
+            // survive this step.
+            wizard.setDockerfile(value || undefined);
           }}
           onCancel={onBack}
         />

src/cli/tui/screens/generate/__tests__/useGenerateWizard.test.tsx

@@ -383,6 +383,28 @@ describe('useGenerateWizard — advanced config gate', () => {
       expect(ref.current!.wizard.step).toBe('confirm');
       vi.useRealTimers();
     });
+
+    it('setDockerfile preserves directory components (no basename stripping)', () => {
+      // Regression test for #1128: the wizard must keep the user-supplied
+      // path intact so useAddAgent.handleCreatePath can resolve it relative
+      // to process.cwd() and copy the file.
+      vi.useFakeTimers();
+      const { ref } = setup();
+      walkToAdvancedWithContainer(ref);
+
+      act(() => ref.current!.wizard.setAdvanced(['dockerfile']));
+      act(() => {
+        vi.runAllTimers();
+      });
+
+      act(() => ref.current!.wizard.setDockerfile('./subdir/Dockerfile.dev'));
+      act(() => {
+        vi.runAllTimers();
+      });
+
+      expect(ref.current!.wizard.config.dockerfile).toBe('./subdir/Dockerfile.dev');
+      vi.useRealTimers();
+    });
   });
 
   describe('filesystem advanced setting', () => {