diff --git a/packages/core/src/services/environmentSanitization.test.ts b/packages/core/src/services/environmentSanitization.test.ts
index cc26d7547d..6d035ac0d3 100644
--- a/packages/core/src/services/environmentSanitization.test.ts
+++ b/packages/core/src/services/environmentSanitization.test.ts
@@ -32,6 +32,28 @@ describe('sanitizeEnvironment', () => {
     expect(sanitized).toEqual(env);
   });
 
+  it('should allow TERM and COLORTERM environment variables', () => {
+    const env = {
+      TERM: 'xterm-256color',
+      COLORTERM: 'truecolor',
+    };
+    const sanitized = sanitizeEnvironment(env, EMPTY_OPTIONS);
+    expect(sanitized).toEqual(env);
+  });
+
+  it('should preserve TERM and COLORTERM even in strict sanitization mode', () => {
+    const env = {
+      GITHUB_SHA: 'abc123',
+      TERM: 'xterm-256color',
+      COLORTERM: 'truecolor',
+      SOME_OTHER_VAR: 'value',
+    };
+    const sanitized = sanitizeEnvironment(env, EMPTY_OPTIONS);
+    expect(sanitized['TERM']).toBe('xterm-256color');
+    expect(sanitized['COLORTERM']).toBe('truecolor');
+    expect(sanitized['SOME_OTHER_VAR']).toBeUndefined();
+  });
+
   it('should allow variables prefixed with GEMINI_CLI_', () => {
     const env = {
       GEMINI_CLI_FOO: 'bar',
diff --git a/packages/core/src/services/environmentSanitization.ts b/packages/core/src/services/environmentSanitization.ts
index dc9c92484d..dba3662513 100644
--- a/packages/core/src/services/environmentSanitization.ts
+++ b/packages/core/src/services/environmentSanitization.ts
@@ -71,6 +71,10 @@ export const ALWAYS_ALLOWED_ENVIRONMENT_VARIABLES: ReadonlySet<string> =
     'TMPDIR',
     'USER',
     'LOGNAME',
+    // Terminal capability variables (needed by editors like vim/emacs and
+    // interactive commands like top)
+    'TERM',
+    'COLORTERM',
     // GitHub Action-related variables
     'ADDITIONAL_CONTEXT',
     'AVAILABLE_LABELS',