diff --git a/.github/workflows/e2e.yml b/.github/workflows/e2e.yml
index 5b20345e3..bc705df72 100644
--- a/.github/workflows/e2e.yml
+++ b/.github/workflows/e2e.yml
@@ -54,7 +54,7 @@ jobs:
           - group: features
             files: "tests/e2e/scenarios/test_skills.py tests/e2e/scenarios/test_tool_approval.py tests/e2e/scenarios/test_webhook.py"
           - group: extensions
-            files: "tests/e2e/scenarios/test_extensions.py tests/e2e/scenarios/test_extension_oauth.py tests/e2e/scenarios/test_telegram_token_validation.py tests/e2e/scenarios/test_telegram_hot_activation.py tests/e2e/scenarios/test_wasm_lifecycle.py tests/e2e/scenarios/test_tool_execution.py tests/e2e/scenarios/test_pairing.py tests/e2e/scenarios/test_mcp_auth_flow.py tests/e2e/scenarios/test_oauth_credential_fallback.py tests/e2e/scenarios/test_routine_oauth_credential_injection.py"
+            files: "tests/e2e/scenarios/test_extensions.py tests/e2e/scenarios/test_extension_oauth.py tests/e2e/scenarios/test_oauth_url_parameters.py tests/e2e/scenarios/test_telegram_token_validation.py tests/e2e/scenarios/test_telegram_hot_activation.py tests/e2e/scenarios/test_wasm_lifecycle.py tests/e2e/scenarios/test_tool_execution.py tests/e2e/scenarios/test_pairing.py tests/e2e/scenarios/test_mcp_auth_flow.py tests/e2e/scenarios/test_oauth_credential_fallback.py tests/e2e/scenarios/test_routine_oauth_credential_injection.py"
           - group: routines
             files: "tests/e2e/scenarios/test_owner_scope.py tests/e2e/scenarios/test_routine_event_batch.py"
     steps:
diff --git a/tests/e2e/scenarios/test_oauth_url_parameters.py b/tests/e2e/scenarios/test_oauth_url_parameters.py
new file mode 100644
index 000000000..0dae3e535
--- /dev/null
+++ b/tests/e2e/scenarios/test_oauth_url_parameters.py
@@ -0,0 +1,249 @@
+"""OAuth URL parameter validation e2e tests.
+
+Tests for bug #992: Google OAuth URL broken when initiated from Telegram.
+Specifically verifies that OAuth query parameters are correctly formatted:
+- "client_id" (with underscore) NOT "clientid" (without underscore)
+- All standard OAuth parameters are present and correctly encoded
+- URLs are consistent across channels (web, Telegram, etc.)
+
+The test verifies:
+1. OAuth URL is generated with correct parameters
+2. URL works with the OAuth provider (Google)
+3. Extra parameters (access_type, prompt) are preserved
+"""
+
+from urllib.parse import parse_qs, urlparse
+import pytest
+
+from helpers import api_post, api_get
+
+
+async def _extract_oauth_params(auth_url: str) -> dict:
+    """Extract and validate OAuth query parameters from auth_url.
+
+    Returns dict with parsed parameters:
+    {
+        'client_id': '...',
+        'redirect_uri': '...',
+        'response_type': 'code',
+        'scope': '...',
+        'state': '...',
+        'access_type': '...',
+        'prompt': '...',
+        ...
+    }
+    """
+    parsed = urlparse(auth_url)
+    qs = parse_qs(parsed.query)
+
+    # Convert lists to single values for easier testing
+    params = {k: v[0] if len(v) > 0 else v for k, v in qs.items()}
+    return params
+
+
+async def _get_extension(ironclaw_server, name):
+    """Get a specific extension from the extensions list, or None."""
+    r = await api_get(ironclaw_server, "/api/extensions")
+    for ext in r.json().get("extensions", []):
+        if ext["name"] == name:
+            return ext
+    return None
+
+
+@pytest.fixture
+async def installed_gmail(ironclaw_server):
+    """Installs the 'gmail' extension before a test and removes it after.
+
+    This fixture handles the setup and teardown of the Gmail extension,
+    ensuring a clean state for each test.
+    """
+    # Ensure Gmail is not installed before test
+    ext = await _get_extension(ironclaw_server, "gmail")
+    if ext:
+        r = await api_post(ironclaw_server, "/api/extensions/gmail/remove", timeout=30)
+        assert r.status_code == 200
+
+    # Install Gmail
+    r = await api_post(
+        ironclaw_server,
+        "/api/extensions/install",
+        json={"name": "gmail"},
+        timeout=180,
+    )
+    assert r.status_code == 200, f"Gmail install failed: {r.text}"
+    assert r.json().get("success") is True, f"Install failed: {r.json().get('message', '')}"
+
+    yield
+
+    # Teardown: remove gmail
+    r = await api_post(ironclaw_server, "/api/extensions/gmail/remove", timeout=30)
+    assert r.status_code == 200, f"Gmail removal failed: {r.text}"
+
+
+@pytest.fixture
+async def auth_url(ironclaw_server, installed_gmail):
+    """Generate and return an OAuth auth URL.
+
+    Requires Gmail to be installed (depends on installed_gmail fixture).
+    """
+    r = await api_post(
+        ironclaw_server,
+        "/api/extensions/gmail/setup",
+        json={"secrets": {}},
+        timeout=30,
+    )
+    assert r.status_code == 200
+    data = r.json()
+    assert data.get("success") is True, f"Setup failed: {data.get('message', '')}"
+
+    url = data.get("auth_url")
+    assert url is not None, f"Expected auth_url in response: {data}"
+    assert "accounts.google.com" in url, f"auth_url should point to Google: {url}"
+
+    return url
+
+
+@pytest.fixture
+async def oauth_params(auth_url):
+    """Extract and return OAuth parameters from auth_url.
+
+    Depends on auth_url fixture.
+    """
+    return await _extract_oauth_params(auth_url)
+
+
+# ─ OAuth URL parameter validation tests ────────────────────────────────
+
+async def test_oauth_url_has_client_id_not_clientid(oauth_params, auth_url):
+    """Verify OAuth URL has 'client_id' (with underscore), NOT 'clientid'.
+
+    Bug #992: Ensure the parameter name is correct across all channels.
+    """
+    params = oauth_params
+
+    # The bug: "clientid" appears instead of "client_id"
+    # Verify the CORRECT parameter name exists
+    assert "client_id" in params, (
+        f"OAuth URL missing 'client_id' parameter. "
+        f"URL: {auth_url}\nParams: {params}"
+    )
+    assert params["client_id"], "client_id should have a value"
+
+    # Verify the INCORRECT parameter name does NOT exist
+    assert "clientid" not in params, (
+        f"OAuth URL should NOT have 'clientid' (without underscore). "
+        f"Bug #992: URL: {auth_url}\nParams: {params}"
+    )
+
+
+async def test_oauth_url_has_required_parameters(oauth_params):
+    """Verify all required OAuth 2.0 parameters are present."""
+    params = oauth_params
+
+    # Required OAuth 2.0 parameters
+    required = ["client_id", "response_type", "redirect_uri", "scope", "state"]
+    for param in required:
+        assert param in params, (
+            f"Missing required OAuth parameter: {param}. "
+            f"Params: {params}"
+        )
+        assert params[param], f"Parameter '{param}' should have a non-empty value"
+
+    # Validate specific values
+    assert params["response_type"] == "code", "Should use authorization_code flow"
+    assert "oauth" in params["redirect_uri"], "Redirect URI should be an OAuth callback"
+
+
+async def test_oauth_url_has_extra_params(oauth_params):
+    """Verify extra_params from capabilities.json are included."""
+    params = oauth_params
+
+    # Google-specific extra_params from gmail-tool.capabilities.json
+    assert "access_type" in params, (
+        "Should include 'access_type' from extra_params"
+    )
+    assert params["access_type"] == "offline", (
+        "access_type should be 'offline' for Gmail"
+    )
+
+    assert "prompt" in params, (
+        "Should include 'prompt' from extra_params"
+    )
+    assert params["prompt"] == "consent", (
+        "prompt should be 'consent' for Gmail"
+    )
+
+
+async def test_oauth_url_is_valid_google_oauth(auth_url):
+    """Verify the URL is a valid Google OAuth 2.0 authorization URL."""
+    # Verify scheme and host
+    parsed = urlparse(auth_url)
+    assert parsed.scheme == "https", "OAuth URL must use HTTPS"
+    assert "accounts.google.com" in parsed.netloc, "Must be Google's OAuth endpoint"
+    assert parsed.path == "/o/oauth2/v2/auth", "Must use Google OAuth 2.0 endpoint"
+
+
+async def test_oauth_url_state_is_unique(ironclaw_server, installed_gmail, oauth_params, auth_url):
+    """Verify CSRF state is present and unique per request."""
+    # Get a new OAuth URL
+    r = await api_post(
+        ironclaw_server,
+        "/api/extensions/gmail/setup",
+        json={"secrets": {}},
+        timeout=30,
+    )
+    assert r.status_code == 200
+    new_auth_url = r.json().get("auth_url")
+    assert new_auth_url is not None
+
+    # Extract state from both URLs
+    original_params = oauth_params
+    new_params = await _extract_oauth_params(new_auth_url)
+
+    original_state = original_params.get("state")
+    new_state = new_params.get("state")
+
+    assert original_state is not None, "Should have state parameter"
+    assert new_state is not None, "New request should have state parameter"
+    assert original_state != new_state, (
+        "CSRF state should be unique per request (for security)"
+    )
+
+
+async def test_oauth_url_escaping(auth_url):
+    """Verify URL query parameters are properly escaped."""
+    # Verify special characters in values are URL-encoded
+    # For example, scopes contain spaces which should be %20
+    assert "%20" in auth_url or "+" in auth_url or "%2B" in auth_url or " " not in auth_url, (
+        "OAuth URL should properly encode special characters in parameters"
+    )
+
+
+# ─ Telegram-specific tests (when Telegram channel is available) ──────────
+
+class TestOAuthURLViaTelegram:
+    """Test OAuth URL generation specifically via Telegram channel.
+
+    These tests would verify that the same OAuth URL works correctly when
+    transmitted through the Telegram WASM channel (as opposed to web gateway).
+
+    Currently marked as xfail pending Telegram channel setup in E2E tests.
+    """
+
+    @pytest.mark.skip(reason="Telegram channel E2E setup not yet implemented")
+    async def test_telegram_oauth_url_has_correct_parameters(self):
+        """Verify OAuth URL sent via Telegram has correct parameter names."""
+        # This test would:
+        # 1. Send a message via Telegram that triggers OAuth
+        # 2. Capture the status update sent to Telegram
+        # 3. Extract the auth_url from the message
+        # 4. Verify it has "client_id" not "clientid"
+        pass
+
+    @pytest.mark.skip(reason="Telegram channel E2E setup not yet implemented")
+    async def test_telegram_oauth_url_can_be_regenerated(self):
+        """Verify OAuth URL can be regenerated when requested via Telegram."""
+        # This test would verify that the bug #992 symptom
+        # "URL cannot be regenerated when asked" is fixed.
+        # If the URL is cached incorrectly, regeneration would fail.
+        pass