comments: support both mcp majors in the MCP server

.github/workflows/ci.yaml

@@ -40,3 +40,28 @@ jobs:
     - name: Test
       run: |
         uv run pytest tests
+
+  mcp:
+    # The mcp extra is not part of `uv sync`, so the build job above never
+    # imports it. Without this, novem.comments.MCP() can break against either
+    # major and the suite stays green.
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        mcp-version: ["mcp>=1,<2", "mcp>=2,<3"]
+
+    steps:
+    - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+    - name: Set up Python
+      uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+      with:
+        python-version: "3.12"
+    - name: Install uv
+      uses: astral-sh/setup-uv@c771a70e6277c0a99b617c7a806ffedaca235ff9 # v9.0.0
+    - name: Install dependencies
+      run: |
+        uv sync
+    - name: Test against ${{ matrix.mcp-version }}
+      run: |
+        uv run --with '${{ matrix.mcp-version }}' pytest tests/test_mcp_compat.py -v

examples/mcp_mention_responder.py

@@ -64,6 +64,17 @@ def _log(msg: Any, text: str) -> None:
     print(f"[{msg.ts}] {text}", file=sys.stderr)
 
 
+def _tool_content(result: Any) -> Any:
+    """The content list from a call_tool result, across mcp v1 and v2.
+
+    v1 returns the list itself, or a (list, dict) tuple when the tool declares
+    structured output. v2 returns a CallToolResult, which is not subscriptable.
+    """
+    if hasattr(result, "content"):
+        return result.content
+    return result[0] if isinstance(result, tuple) else result
+
+
 async def _handle(msg: Any) -> None:
     _log(msg, f"event: {msg.event_type} from @{msg.actor} -> {msg.fqnp}")
 
@@ -107,7 +118,7 @@ def on_reply(text: str) -> str:
     if msg.actor != my_username:
         _log(msg, "posting 'On it!' acknowledgement")
         ack_result = await mcp.call_tool("novem_reply", {"text": "On it!"})
-        ack_text = ack_result[0][0].text if isinstance(ack_result, tuple) else ack_result[0].text
+        ack_text = _tool_content(ack_result)[0].text
         _log(msg, f"  ack result: {ack_text}")
     else:
         _log(msg, "actor is us, skipping acknowledgement")
@@ -170,14 +181,18 @@ def on_reply(text: str) -> str:
                 _log(msg, f"  tool {block.name} error: {e}")
                 results.append({"type": "tool_result", "tool_use_id": block.id, "content": str(e), "is_error": True})
                 continue
-            content = result[0] if isinstance(result, tuple) else result
+            content = _tool_content(result)
             result_content: List[Any] = []
             for item in content:
                 if item.type == "image":
                     result_content.append(
                         {
                             "type": "image",
-                            "source": {"type": "base64", "media_type": item.mimeType, "data": item.data},
+                            "source": {
+                                "type": "base64",
+                                "media_type": getattr(item, "mime_type", None) or item.mimeType,
+                                "data": item.data,
+                            },
                         }
                     )
                 else:

novem/comments.py

@@ -7,6 +7,7 @@
 """
 
 import asyncio
+import importlib
 import json
 import time
 from dataclasses import dataclass, field
@@ -661,13 +662,25 @@ def _do_reply(self, text: str, title: Optional[str] = None) -> str:
 # ---------------------------------------------------------------------------
 
 
-def _check_mcp_deps() -> Any:
-    try:
-        from mcp.server.fastmcp import FastMCP  # type: ignore[import-untyped,import-not-found]
+def _import_mcp(symbol: str) -> Any:
+    """Resolve an mcp symbol across the v1/v2 module split.
+
+    mcp 2.x moved mcp.server.fastmcp to mcp.server.mcpserver and renamed
+    FastMCP to MCPServer. Both spellings are tried so an installed 2.x is not
+    reported as a missing dependency, which is what a bare ImportError here
+    used to claim -- ModuleNotFoundError is an ImportError.
+    """
+    v2_name = {"FastMCP": "MCPServer"}.get(symbol, symbol)
+    for module, name in (("mcp.server.fastmcp", symbol), ("mcp.server.mcpserver", v2_name)):
+        try:
+            return getattr(importlib.import_module(module), name)
+        except (ImportError, AttributeError):
+            continue
+    raise ImportError('The "mcp" extra is required. Install with: pip install novem[mcp]')
+
 
-        return FastMCP
-    except ImportError:
-        raise ImportError('The "mcp" extra is required. Install with: pip install novem[mcp]')
+def _check_mcp_deps() -> Any:
+    return _import_mcp("FastMCP")
 
 
 def _fmt_comment(c: Comment, indent: int = 0) -> str:
@@ -805,7 +818,8 @@ async def api_tools() -> List[Dict[str, Any]]:
             {
                 "name": t.name,
                 "description": t.description or "",
-                "input_schema": t.inputSchema,
+                # mcp 2.x renamed the field to input_schema
+                "input_schema": getattr(t, "input_schema", None) or t.inputSchema,
             }
             for t in mcp_tools
         ]
@@ -884,7 +898,7 @@ def novem_get_vis_screenshot() -> Any:
         are looking at.  Only available when the FQNP points to a
         visualization (plot, grid, mail, …).
         """
-        from mcp.server.fastmcp import Image  # type: ignore[import-untyped,import-not-found]
+        Image = _import_mcp("Image")
 
         if not parsed.is_vis:
             return "This FQNP does not reference a visualization."

pyproject.toml

@@ -28,10 +28,10 @@ compute = [
     "aiohttp>=3.9",
 ]
 mcp = [
-    # novem.comments.MCP() targets the v1 API (mcp.server.fastmcp.FastMCP,
-    # Tool.inputSchema).  mcp 2.0 removed both, so keep the extra on 1.x
-    # until the migration lands -- see the tracking issue.
-    "mcp>=1.0.0,<2",
+    # novem.comments.MCP() resolves both spellings: v1's
+    # mcp.server.fastmcp.FastMCP/Tool.inputSchema and v2's
+    # mcp.server.mcpserver.MCPServer/Tool.input_schema.
+    "mcp>=1.0.0,<3",
 ]
 
 [project.urls]

tests/test_mcp_compat.py

@@ -0,0 +1,47 @@
+"""The mcp extra is optional, so nothing else in the suite imports it.
+
+mcp 2.x renamed FastMCP to MCPServer and moved it out of mcp.server.fastmcp,
+and renamed Tool.inputSchema to input_schema. These pin the surface
+novem.comments.MCP() actually touches, against whichever major is installed.
+"""
+
+import asyncio
+
+import pytest
+
+pytest.importorskip("mcp", reason="the mcp extra is not installed")
+
+from novem.comments import _import_mcp  # noqa: E402
+
+
+def test_server_symbol_resolves_on_either_major():
+    assert _import_mcp("FastMCP").__name__ in {"FastMCP", "MCPServer"}
+
+
+def test_image_symbol_resolves_on_either_major():
+    assert _import_mcp("Image").__name__ == "Image"
+
+
+def test_missing_symbol_reports_the_extra():
+    with pytest.raises(ImportError, match="mcp"):
+        _import_mcp("NoSuchSymbolAnywhere")
+
+
+def test_server_exposes_the_api_the_helper_uses():
+    server = _import_mcp("FastMCP")("novem-comments (probe)")
+    for attr in ("tool", "list_tools", "run"):
+        assert hasattr(server, attr), f"server has no {attr}()"
+
+
+def test_tool_input_schema_is_reachable():
+    """Mirrors the api_tools() lookup in novem/comments.py."""
+    server = _import_mcp("FastMCP")("novem-comments (probe)")
+
+    @server.tool()
+    def hello(name: str) -> str:
+        """Say hello."""
+        return f"hi {name}"
+
+    tool = asyncio.run(server.list_tools())[0]
+    assert tool.name == "hello"
+    assert getattr(tool, "input_schema", None) or tool.inputSchema