Explain: track usage in telemetry and keyserver (when possible)

explain/agents.py

@@ -25,6 +25,9 @@ class BaseAgent(ABC):
     name: ClassVar[str]
     program_name: ClassVar[str]
     display_name: ClassVar[str]
+    # Name reported to the keyserver for usage tracking. Override in subclasses if the
+    # agent name doesn't match the `SupportedAgent` enum in UDB.
+    usage_name: ClassVar[str | None] = None
 
     def __init_subclass__(cls, **kwargs):
         super().__init_subclass__(**kwargs)

explain/claude_agent.py

@@ -26,6 +26,7 @@ class ClaudeAgent(BaseAgent):
     name: ClassVar[str] = "claude"
     program_name: ClassVar[str] = "claude"
     display_name: ClassVar[str] = "Claude Code"
+    usage_name: ClassVar[str] = "claude-code"
 
     @classmethod
     def find_binary(cls) -> Path | None:

explain/copilot_cli_agent.py

@@ -28,6 +28,7 @@ class CopilotCLIAgent(BaseAgent):
     name: ClassVar[str] = "copilot"
     program_name: ClassVar[str] = "copilot"
     display_name: ClassVar[str] = "Copilot CLI"
+    usage_name: ClassVar[str] = "github-copilot-cli"
 
     async def _handle_messages(self, stdout: asyncio.StreamReader) -> str:
         """

explain/explain.py

@@ -81,6 +81,24 @@ def _validate_log_level(level: str) -> LogLevel:
 agent: BaseAgent | None = None
 """Agent instance for the current session."""
 
+_ai_usage_tracked_in_keyserver = False
+
+
+def _track_ai_usage(udb: udb_base.Udb, usage_name: str) -> None:
+    """
+    Track AI Gen 1 usage in telemetry and keyserver.
+
+    Errors are silently ignored so that tracking failures never prevents the command from running.
+    """
+    with contextlib.suppress(Exception):
+        udb.telemetry_session.data.licensing.used_licensable_features.ai_gen1 = True
+
+    global _ai_usage_tracked_in_keyserver
+    with contextlib.suppress(Exception):
+        _ai_usage_tracked_in_keyserver = udb.keyclient_communicator.log_session_meta(
+            "ai_gen1", usage_name
+        )
+
 
 @contextlib.contextmanager
 def temporary_gdb_settings(udb: udb_base.Udb) -> Iterator[None]:
@@ -971,6 +989,7 @@ def uexperimental__mcp__serve(udb: udb_base.Udb, args: Any) -> None:
     """
     Start an MCP server for this UDB instance.
     """
+    _track_ai_usage(udb, "mcp-serve")  # We don't know the agent name when used as an MCP server.
     gateway = UdbMcpGateway(udb)
     with temporary_gdb_settings(udb):
         run_server(gateway, args.port)
@@ -1052,6 +1071,8 @@ def explain(udb: udb_base.Udb, args: Any) -> None:
     if not event_loop:
         event_loop = asyncio.new_event_loop()
 
+    _track_ai_usage(udb, agent.usage_name or agent.name)
+
     # Don't allow debuggee standard streams or user breakpoints, they will confuse the LLM.
     with temporary_gdb_settings(udb):
         explanation = event_loop.run_until_complete(explain_query(agent, gateway, why))