perf(ttft): salvage easy-win startup optimizations from #3346 (#3395)

* perf(ttft): dedupe shared tool availability checks

* perf(ttft): short-circuit vision auto-resolution

* perf(ttft): make Claude Code version detection lazy

* perf(ttft): reuse loaded toolsets for skills prompt

---------

Co-authored-by: kshitijk4poor <82637225+kshitijk4poor@users.noreply.github.com>

tests/agent/test_auxiliary_client.py

@@ -11,6 +11,7 @@ from agent.auxiliary_client import (
     get_text_auxiliary_client,
     get_vision_auxiliary_client,
     get_available_vision_backends,
+    resolve_vision_provider_client,
     resolve_provider_client,
     auxiliary_max_tokens_param,
     _read_codex_access_token,
@@ -638,6 +639,30 @@ class TestVisionClientFallback:
         assert client.__class__.__name__ == "AnthropicAuxiliaryClient"
         assert model == "claude-haiku-4-5-20251001"
 
+    def test_selected_codex_provider_short_circuits_vision_auto(self, monkeypatch):
+        def fake_load_config():
+            return {"model": {"provider": "openai-codex", "default": "gpt-5.2-codex"}}
+
+        codex_client = MagicMock()
+        with (
+            patch("hermes_cli.config.load_config", fake_load_config),
+            patch("agent.auxiliary_client._try_codex", return_value=(codex_client, "gpt-5.2-codex")) as mock_codex,
+            patch("agent.auxiliary_client._try_openrouter") as mock_openrouter,
+            patch("agent.auxiliary_client._try_nous") as mock_nous,
+            patch("agent.auxiliary_client._try_anthropic") as mock_anthropic,
+            patch("agent.auxiliary_client._try_custom_endpoint") as mock_custom,
+        ):
+            provider, client, model = resolve_vision_provider_client()
+
+        assert provider == "openai-codex"
+        assert client is codex_client
+        assert model == "gpt-5.2-codex"
+        mock_codex.assert_called_once()
+        mock_openrouter.assert_not_called()
+        mock_nous.assert_not_called()
+        mock_anthropic.assert_not_called()
+        mock_custom.assert_not_called()
+
     def test_vision_auto_includes_codex(self, codex_auth_dir):
         """Codex supports vision (gpt-5.3-codex), so auto mode should use it."""
         with patch("agent.auxiliary_client._read_nous_auth", return_value=None), \

tests/test_run_agent.py

@@ -584,6 +584,38 @@ class TestBuildSystemPrompt:
         # Should contain current date info like "Conversation started:"
         assert "Conversation started:" in prompt
 
+    def test_skills_prompt_derives_available_toolsets_from_loaded_tools(self):
+        tools = _make_tool_defs("web_search", "skills_list", "skill_view", "skill_manage")
+        toolset_map = {
+            "web_search": "web",
+            "skills_list": "skills",
+            "skill_view": "skills",
+            "skill_manage": "skills",
+        }
+
+        with (
+            patch("run_agent.get_tool_definitions", return_value=tools),
+            patch(
+                "run_agent.check_toolset_requirements",
+                side_effect=AssertionError("should not re-check toolset requirements"),
+            ),
+            patch("run_agent.get_toolset_for_tool", create=True, side_effect=toolset_map.get),
+            patch("run_agent.build_skills_system_prompt", return_value="SKILLS_PROMPT") as mock_skills,
+            patch("run_agent.OpenAI"),
+        ):
+            agent = AIAgent(
+                api_key="test-k...7890",
+                quiet_mode=True,
+                skip_context_files=True,
+                skip_memory=True,
+            )
+
+            prompt = agent._build_system_prompt()
+
+        assert "SKILLS_PROMPT" in prompt
+        assert mock_skills.call_args.kwargs["available_tools"] == set(toolset_map)
+        assert mock_skills.call_args.kwargs["available_toolsets"] == {"web", "skills"}
+
 
 class TestInvalidateSystemPrompt:
     def test_clears_cache(self, agent):

tests/tools/test_registry.py

@@ -81,6 +81,33 @@ class TestGetDefinitions:
         assert len(defs) == 1
         assert defs[0]["function"]["name"] == "available"
 
+    def test_reuses_shared_check_fn_once_per_call(self):
+        reg = ToolRegistry()
+        calls = {"count": 0}
+
+        def shared_check():
+            calls["count"] += 1
+            return True
+
+        reg.register(
+            name="first",
+            toolset="shared",
+            schema=_make_schema("first"),
+            handler=_dummy_handler,
+            check_fn=shared_check,
+        )
+        reg.register(
+            name="second",
+            toolset="shared",
+            schema=_make_schema("second"),
+            handler=_dummy_handler,
+            check_fn=shared_check,
+        )
+
+        defs = reg.get_definitions({"first", "second"})
+        assert len(defs) == 2
+        assert calls["count"] == 1
+
 
 class TestUnknownToolDispatch:
     def test_returns_error_json(self):