diff --git a/docs/cli/plan-mode.md b/docs/cli/plan-mode.md
index f5532a07ca..4d9c45ce17 100644
--- a/docs/cli/plan-mode.md
+++ b/docs/cli/plan-mode.md
@@ -327,8 +327,12 @@ Storage whenever Gemini CLI exits Plan Mode to start the implementation.
 
 ```bash
 #!/usr/bin/env bash
-# Extract the plan path from the tool input JSON
-plan_path=$(jq -r '.tool_input.plan_path // empty')
+# Extract the plan filename from the tool input JSON
+plan_filename=$(jq -r '.tool_input.plan_filename // empty')
+plan_filename=$(basename -- "$plan_filename")
+
+# Construct the absolute path using the GEMINI_PLANS_DIR environment variable
+plan_path="$GEMINI_PLANS_DIR/$plan_filename"
 
 if [ -f "$plan_path" ]; then
   # Generate a unique filename using a timestamp
diff --git a/docs/hooks/index.md b/docs/hooks/index.md
index 0d6ae6d447..0125a28eb2 100644
--- a/docs/hooks/index.md
+++ b/docs/hooks/index.md
@@ -138,6 +138,7 @@ multiple layers in the following order of precedence (highest to lowest):
 Hooks are executed with a sanitized environment.
 
 - `GEMINI_PROJECT_DIR`: The absolute path to the project root.
+- `GEMINI_PLANS_DIR`: The absolute path to the plans directory.
 - `GEMINI_SESSION_ID`: The unique ID for the current session.
 - `GEMINI_CWD`: The current working directory.
 - `CLAUDE_PROJECT_DIR`: (Alias) Provided for compatibility.
diff --git a/packages/core/src/hooks/hookRunner.test.ts b/packages/core/src/hooks/hookRunner.test.ts
index 9cee6575fe..5b155a8516 100644
--- a/packages/core/src/hooks/hookRunner.test.ts
+++ b/packages/core/src/hooks/hookRunner.test.ts
@@ -76,6 +76,9 @@ describe('HookRunner', () => {
       sanitizationConfig: {
         enableEnvironmentVariableRedaction: true,
       },
+      storage: {
+        getPlansDir: vi.fn().mockReturnValue('/test/project/plans'),
+      },
     } as unknown as Config;
 
     hookRunner = new HookRunner(mockConfig);
@@ -370,12 +373,51 @@ describe('HookRunner', () => {
             shell: false,
             env: expect.objectContaining({
               GEMINI_PROJECT_DIR: '/test/project',
+              GEMINI_PLANS_DIR: '/test/project/plans',
+              GEMINI_CWD: '/test/project',
+              GEMINI_SESSION_ID: 'test-session',
               CLAUDE_PROJECT_DIR: '/test/project',
             }),
           }),
         );
       });
 
+      it('should expand and escape GEMINI_PLANS_DIR in commands', async () => {
+        const configWithEnvVar: HookConfig = {
+          type: HookType.Command,
+          command: 'ls $GEMINI_PLANS_DIR',
+        };
+
+        // Change plans dir to one with spaces
+        vi.mocked(mockConfig.storage.getPlansDir).mockReturnValue(
+          '/test/project/plans with spaces',
+        );
+
+        mockSpawn.mockProcessOn.mockImplementation(
+          (event: string, callback: (code: number) => void) => {
+            if (event === 'close') {
+              setImmediate(() => callback(0));
+            }
+          },
+        );
+
+        await hookRunner.executeHook(
+          configWithEnvVar,
+          HookEventName.BeforeTool,
+          mockInput,
+        );
+
+        expect(spawn).toHaveBeenCalledWith(
+          expect.stringMatching(/bash|powershell/),
+          expect.arrayContaining([
+            expect.stringMatching(
+              /ls ['"]\/test\/project\/plans with spaces['"]/,
+            ),
+          ]),
+          expect.any(Object),
+        );
+      });
+
       it('should not allow command injection via GEMINI_PROJECT_DIR', async () => {
         const maliciousCwd = '/test/project; echo "pwned" > /tmp/pwned';
         const mockMaliciousInput: HookInput = {
diff --git a/packages/core/src/hooks/hookRunner.ts b/packages/core/src/hooks/hookRunner.ts
index 812deafcbe..4c199ebfc7 100644
--- a/packages/core/src/hooks/hookRunner.ts
+++ b/packages/core/src/hooks/hookRunner.ts
@@ -348,6 +348,9 @@ export class HookRunner {
       const env = {
         ...sanitizeEnvironment(process.env, this.config.sanitizationConfig),
         GEMINI_PROJECT_DIR: input.cwd,
+        GEMINI_PLANS_DIR: this.config.storage.getPlansDir(),
+        GEMINI_CWD: input.cwd,
+        GEMINI_SESSION_ID: input.session_id,
         CLAUDE_PROJECT_DIR: input.cwd, // For compatibility
         ...hookConfig.env,
       };
@@ -514,8 +517,17 @@ export class HookRunner {
   ): string {
     debugLogger.debug(`Expanding hook command: ${command} (cwd: ${input.cwd})`);
     const escapedCwd = escapeShellArg(input.cwd, shellType);
+    const escapedPlansDir = escapeShellArg(
+      this.config.storage.getPlansDir(),
+      shellType,
+    );
+    const escapedSessionId = escapeShellArg(input.session_id, shellType);
+
     return command
       .replace(/\$GEMINI_PROJECT_DIR/g, () => escapedCwd)
+      .replace(/\$GEMINI_CWD/g, () => escapedCwd)
+      .replace(/\$GEMINI_PLANS_DIR/g, () => escapedPlansDir)
+      .replace(/\$GEMINI_SESSION_ID/g, () => escapedSessionId)
       .replace(/\$CLAUDE_PROJECT_DIR/g, () => escapedCwd); // For compatibility
   }