Improve User-Agent attribution for agentic callers

.changes/next-release/enhancement-UserAgent-78213.json

@@ -0,0 +1,5 @@
+{
+  "type": "enhancement",
+  "category": "User Agent",
+  "description": "Improve User-Agent attribution for agentic callers."
+}

awscli/botocore/useragent.py

@@ -104,7 +104,29 @@
     'FLEXIBLE_CHECKSUMS_REQ_XXHASH3': 'AG',
     'FLEXIBLE_CHECKSUMS_REQ_XXHASH64': 'AH',
     'FLEXIBLE_CHECKSUMS_REQ_XXHASH128': 'AI',
+    'AGENTIC_CALLER_CLAUDE_CODE': 'AN',
+    'AGENTIC_CALLER_GEMINI_CLI': 'AO',
+    'AGENTIC_CALLER_CODEX': 'AP',
+    'AGENTIC_CALLER_KIRO': 'AQ',
+    'AGENTIC_CALLER_OPENCODE': 'AR',
+    'AGENTIC_CALLER_ANTIGRAVITY': 'AS',
+    'AGENTIC_CALLER_AMP': 'AT',
+    'AGENTIC_CALLER_PI': 'AU',
+    'AGENTIC_CALLER_COPILOT_CLI': 'AV',
+    'AGENTIC_CALLER_CURSOR': 'AW',
 }
+_USERAGENT_AGENTIC_CALLER_ENV_VAR_MAPPINGS = (
+    ('CLAUDECODE', 'AGENTIC_CALLER_CLAUDE_CODE', '1'),
+    ('GEMINI_CLI', 'AGENTIC_CALLER_GEMINI_CLI', '1'),
+    ('CODEX_THREAD_ID', 'AGENTIC_CALLER_CODEX', None),
+    ('KIRO_SESSION_ID', 'AGENTIC_CALLER_KIRO', None),
+    ('OPENCODE', 'AGENTIC_CALLER_OPENCODE', None),
+    ('ANTIGRAVITY_AGENT', 'AGENTIC_CALLER_ANTIGRAVITY', None),
+    ('AMP_CURRENT_THREAD_ID', 'AGENTIC_CALLER_AMP', None),
+    ('PI_CODING_AGENT', 'AGENTIC_CALLER_PI', 'true'),
+    ('COPILOT_CLI', 'AGENTIC_CALLER_COPILOT_CLI', '1'),
+    ('CURSOR_AGENT', 'AGENTIC_CALLER_CURSOR', '1'),
+)
 
 
 def register_feature_id(feature_id):
@@ -136,6 +158,27 @@ def register_feature_ids(feature_ids):
         register_feature_id(feature_id)
 
 
+def _agentic_env_var_is_set(env_var, expected_value):
+    """
+    Returns true if an environment variable is set,
+    optionally with specific value
+    """
+    value = os.environ.get(env_var)
+    if expected_value is None:
+        return value not in (None, '')
+    return value == expected_value
+
+
+def _register_agentic_caller_env_features():
+    for (
+        env_var,
+        feature_id,
+        expected_value,
+    ) in _USERAGENT_AGENTIC_CALLER_ENV_VAR_MAPPINGS:
+        if _agentic_env_var_is_set(env_var, expected_value):
+            register_feature_id(feature_id)
+
+
 def sanitize_user_agent_string_component(raw_str, allow_hash):
     """Replaces all not allowed characters in the string with a dash ("-").
 
@@ -549,6 +592,7 @@ def _build_feature_metadata(self):
         Returns a single component with prefix "m" followed by a list of
         comma-separated metric values.
         """
+        _register_agentic_caller_env_features()
         ctx = get_context()
         context_features = set() if ctx is None else ctx.features
         client_features = self._client_features or set()

tests/functional/botocore/test_useragent.py

@@ -57,6 +57,27 @@ def captured_ua_string(self):
         return None
 
 
+_AGENTIC_CALLER_ENV_FEATURE_MAPPINGS = (
+    ('CLAUDECODE', '1', 'AN'),
+    ('GEMINI_CLI', '1', 'AO'),
+    ('CODEX_THREAD_ID', 'thread-id', 'AP'),
+    ('KIRO_SESSION_ID', 'session-id', 'AQ'),
+    ('OPENCODE', '1', 'AR'),
+    ('ANTIGRAVITY_AGENT', '1', 'AS'),
+    ('AMP_CURRENT_THREAD_ID', 'thread-id', 'AT'),
+    ('PI_CODING_AGENT', 'true', 'AU'),
+    ('COPILOT_CLI', '1', 'AV'),
+    ('CURSOR_AGENT', '1', 'AW'),
+)
+
+
+@pytest.fixture(autouse=True)
+def clear_agentic_caller_env(monkeypatch):
+    """Unset agentic tool env vars that could affect user-agent tests."""
+    for env_var, _, _ in _AGENTIC_CALLER_ENV_FEATURE_MAPPINGS:
+        monkeypatch.delenv(env_var, raising=False)
+
+
 @pytest.mark.parametrize(
     'sess_name, sess_version, sess_extra, cfg_extra, cfg_appid',
     # Produce every combination of User-Agent related config settings other
@@ -229,6 +250,22 @@ def test_user_agent_has_registered_feature_id(patched_session):
     assert 'C' in feature_list
 
 
+@pytest.mark.parametrize(
+    'env_var, env_value, expected_feature',
+    _AGENTIC_CALLER_ENV_FEATURE_MAPPINGS,
+)
+def test_user_agent_has_agentic_caller_feature_id(
+    patched_session, monkeypatch, env_var, env_value, expected_feature
+):
+    monkeypatch.setenv(env_var, env_value)
+    client_s3 = patched_session.create_client('s3')
+    with UACapHTTPStubber(client_s3) as stub_client:
+        client_s3.list_buckets()
+
+    feature_list = parse_registered_feature_ids(stub_client.captured_ua_string)
+    assert expected_feature in feature_list
+
+
 def test_registered_feature_ids_dont_bleed_between_requests(patched_session):
     client_s3 = patched_session.create_client('s3')
     with UACapHTTPStubber(client_s3) as stub_client:

tests/unit/botocore/test_useragent.py

@@ -26,6 +26,29 @@
     sanitize_user_agent_string_component,
 )
 
+_AGENTIC_CALLER_ENV_VARS = (
+    'CLAUDECODE',
+    'GEMINI_CLI',
+    'CODEX_THREAD_ID',
+    'KIRO_SESSION_ID',
+    'OPENCODE',
+    'ANTIGRAVITY_AGENT',
+    'AMP_CURRENT_THREAD_ID',
+    'PI_CODING_AGENT',
+    'COPILOT_CLI',
+    'CURSOR_AGENT',
+)
+
+
+@pytest.fixture(autouse=True)
+def clear_agentic_caller_env(monkeypatch):
+    """
+    Unset any env vars from agentic tools running the user-agent
+    tests which could influence the user-agent
+    """
+    for env_var in _AGENTIC_CALLER_ENV_VARS:
+        monkeypatch.delenv(env_var, raising=False)
+
 
 @pytest.mark.parametrize(
     'raw_str, allow_hash, expected_str',
@@ -259,4 +282,4 @@ def test_hash_in_user_agent_appid():
         'exec-env/AWS_Lambda_python3.8 '
         'app/fooapp#1.0.0'
     )
-    assert actual == expected
+    assert actual == expected