fix(#2557): Gemini/Antigravity local hook commands use relative paths, not \$CLAUDE_PROJECT_DIR (#2589)

\$CLAUDE_PROJECT_DIR is Claude Code-specific. Gemini CLI doesn't set it, and on
Windows its path-join logic doubled the value producing unresolvable paths like
D:\Projects\GSD\'D:\Projects\GSD'. Gemini runs project hooks with project root
as cwd, so bare relative paths (e.g. node .gemini/hooks/gsd-check-update.js)
are cross-platform and correct. Claude Code and others still use the env var.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

bin/install.js

@@ -6075,9 +6075,13 @@ function install(isGlobal, runtime = 'claude') {
     return;
   }
   const settings = validateHookFields(cleanupOrphanedHooks(rawSettings));
-  // Local installs anchor paths to $CLAUDE_PROJECT_DIR so hooks resolve
-  // correctly regardless of the shell's current working directory (#1906).
-  const localPrefix = '"$CLAUDE_PROJECT_DIR"/' + dirName;
+  // Local installs anchor hook paths so they resolve regardless of cwd (#1906).
+  // Claude Code sets $CLAUDE_PROJECT_DIR; Gemini/Antigravity do not — and on
+  // Windows their own substitution logic doubles the path (#2557). Those runtimes
+  // run project hooks with the project dir as cwd, so bare relative paths work.
+  const localPrefix = (runtime === 'gemini' || runtime === 'antigravity')
+    ? dirName
+    : '"$CLAUDE_PROJECT_DIR"/' + dirName;
   const hookOpts = { portableHooks: hasPortableHooks };
   const statuslineCommand = isGlobal
     ? buildHookCommand(targetDir, 'gsd-statusline.js', hookOpts)

tests/bug-1906-hook-relative-paths.test.cjs

@@ -42,9 +42,11 @@ describe('bug #1906: local hook commands use $CLAUDE_PROJECT_DIR', () => {
     src = fs.readFileSync(INSTALL_SRC, 'utf-8');
   });
 
-  test('localPrefix variable is defined with $CLAUDE_PROJECT_DIR', () => {
-    assert.match(src, /const localPrefix\s*=\s*['"]\"\$CLAUDE_PROJECT_DIR['"]\s*\//,
-      'localPrefix should be defined using $CLAUDE_PROJECT_DIR');
+  test('localPrefix definition includes $CLAUDE_PROJECT_DIR for non-Gemini runtimes', () => {
+    // localPrefix is now a ternary — Gemini/Antigravity use bare dirName (#2557),
+    // all other runtimes use "$CLAUDE_PROJECT_DIR"/ to anchor hook paths.
+    assert.match(src, /const localPrefix\s*=[\s\S]*?"\$CLAUDE_PROJECT_DIR"/,
+      'localPrefix definition must include "$CLAUDE_PROJECT_DIR" branch for non-Gemini runtimes');
   });
 
   for (const hook of HOOKS) {

tests/bug-2557-gemini-local-hook-paths.test.cjs

@@ -0,0 +1,74 @@
+'use strict';
+
+/**
+ * Bug #2557: Gemini CLI local hook commands must NOT use $CLAUDE_PROJECT_DIR.
+ *
+ * $CLAUDE_PROJECT_DIR is a Claude Code-specific env variable. Gemini CLI does
+ * not set it. On Windows, Gemini's own variable-substitution + path-join logic
+ * produced a doubled path like `D:\Projects\GSD\'D:\Projects\GSD'`, causing
+ * every local project hook to fail at SessionStart.
+ *
+ * Fix: localPrefix is now runtime-conditional. Gemini/Antigravity use bare
+ * dirName (relative path) since they always run project hooks with the project
+ * dir as cwd. Claude Code and others still use "$CLAUDE_PROJECT_DIR"/ (#1906).
+ */
+
+const { describe, test, before } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const INSTALL_SRC = path.join(__dirname, '..', 'bin', 'install.js');
+
+describe('bug #2557: Gemini/Antigravity local hooks use relative paths (not $CLAUDE_PROJECT_DIR)', () => {
+  let src;
+
+  before(() => {
+    src = fs.readFileSync(INSTALL_SRC, 'utf-8');
+  });
+
+  test('localPrefix is a ternary that branches on Gemini/Antigravity', () => {
+    assert.match(
+      src,
+      /const localPrefix\s*=\s*\(runtime\s*===\s*['"]gemini['"]/,
+      'localPrefix must branch on runtime === "gemini"',
+    );
+  });
+
+  test('Gemini/Antigravity branch of localPrefix uses bare dirName (relative path)', () => {
+    // The ternary must assign `dirName` (not `"$CLAUDE_PROJECT_DIR"/` + dirName)
+    // for the Gemini branch so hooks use a relative path on all platforms.
+    assert.match(
+      src,
+      /const localPrefix\s*=\s*\(runtime\s*===\s*['"]gemini['"]\s*\|\|\s*runtime\s*===\s*['"]antigravity['"]\)\s*\n?\s*\?\s*dirName/,
+      'Gemini/Antigravity branch must resolve to bare dirName',
+    );
+  });
+
+  test('non-Gemini branch of localPrefix uses "$CLAUDE_PROJECT_DIR"/', () => {
+    // The else branch must still use "$CLAUDE_PROJECT_DIR"/ to fix #1906 for
+    // Claude Code and other runtimes that do set the variable.
+    assert.match(
+      src,
+      /:\s*['"]\"\$CLAUDE_PROJECT_DIR\"\//,
+      'non-Gemini branch must use "$CLAUDE_PROJECT_DIR"/ prefix',
+    );
+  });
+
+  test('Gemini/Antigravity hook commands do not contain "$CLAUDE_PROJECT_DIR" literal', () => {
+    // Since localPrefix is now dirName for Gemini/Antigravity, no command
+    // string built via `localPrefix` should contain the variable literal.
+    // We verify by checking that the only occurrence of $CLAUDE_PROJECT_DIR
+    // in the localPrefix definition is in the non-Gemini (else) branch.
+    const lines = src.split('\n');
+    const prefixDefIdx = lines.findIndex(l => /const localPrefix\s*=/.test(l));
+    assert.ok(prefixDefIdx >= 0, 'localPrefix definition not found');
+    // The Gemini (truthy) branch is the line right after the ternary condition.
+    // It must NOT contain $CLAUDE_PROJECT_DIR.
+    const geminiLine = lines[prefixDefIdx + 1] || '';
+    assert.ok(
+      !geminiLine.includes('$CLAUDE_PROJECT_DIR'),
+      'Gemini branch of localPrefix must not reference $CLAUDE_PROJECT_DIR',
+    );
+  });
+});