prototype: fastmcp 4.x tasks extension (SEP-2663) against wait_for_text

pyproject.toml

@@ -41,7 +41,8 @@ include = [
 
 dependencies = [
   "libtmux>=0.62.0,<1.0",
-  "fastmcp>=3.4.2,<4.0.0",
+  "fastmcp==4.0.0a2",
+  "fastmcp-tasks==4.0.0a2",
 ]
 
 [project.urls]
@@ -111,7 +112,24 @@ lint = [
 requires = ["hatchling"]
 build-backend = "hatchling.build"
 
+[tool.uv]
+# SPIKE ONLY (branch `tasks`). fastmcp 4.x is published as an alpha, so
+# resolution needs pre-releases enabled. Declaring it here rather than
+# relying on UV_PRERELEASE in the environment: uv records the mode it
+# resolved under in uv.lock, so without this every `uv sync` / `uv lock`
+# that forgot the variable fails the lockfile check.
+prerelease = "allow"
+
 [tool.uv.exclude-newer-package]
+# SPIKE ONLY (branch `tasks`): the fastmcp 4.x alpha is younger than the
+# 3-day cooldown. Exempted here so this throwaway worktree can evaluate it;
+# this must never reach a shipping branch.
+fastmcp = false
+fastmcp-slim = false
+fastmcp-tasks = false
+mcp-types = false
+mcp = false
+pydocket = false
 # git-pull packages release in lockstep with their workspaces, so a
 # fresh release blocking on the 3-day cooldown blocks every
 # contributor's `uv sync` until it clears. `false` exempts each

src/libtmux_mcp/middleware.py

@@ -40,7 +40,7 @@
 from fastmcp.server.middleware.response_limiting import ResponseLimitingMiddleware
 from fastmcp.tools.base import ToolResult
 from libtmux import exc as libtmux_exc
-from mcp.types import CallToolRequestParams, TextContent
+from mcp_types import CallToolRequestParams, TextContent
 from pydantic import ValidationError as PydanticValidationError
 
 from libtmux_mcp._utils import (

tests/test_middleware.py

@@ -12,7 +12,7 @@
 from fastmcp.exceptions import ToolError
 from fastmcp.server.middleware import MiddlewareContext
 from libtmux import exc as libtmux_exc
-from mcp.types import CallToolRequestParams
+from mcp_types import CallToolRequestParams
 
 from libtmux_mcp._utils import TAG_DESTRUCTIVE, TAG_MUTATING, TAG_READONLY
 from libtmux_mcp.middleware import (
@@ -592,7 +592,7 @@ def test_audit_middleware_redacts_sensitive_args(
 
 def test_tail_preserving_truncation_keeps_tail() -> None:
     """Over-sized text is truncated from the head, tail is preserved."""
-    from mcp.types import TextContent
+    from mcp_types import TextContent
 
     from libtmux_mcp.middleware import TailPreservingResponseLimitingMiddleware
 
@@ -615,7 +615,7 @@ def test_tail_preserving_truncation_keeps_tail() -> None:
 
 def test_tail_preserving_passthrough_when_under_cap() -> None:
     """Text within the cap passes through unchanged."""
-    from mcp.types import TextContent
+    from mcp_types import TextContent
 
     from libtmux_mcp.middleware import TailPreservingResponseLimitingMiddleware
 
@@ -1560,14 +1560,14 @@ def test_unexpected_argument_suggestion(
     and flags ``wait_for_previous`` as a client scheduling leak, naming
     the client from the MCP initialize handshake when available.
     """
-    import mcp.types
+    import mcp_types
     from fastmcp import Client
 
     probe = _error_probe_server()
 
     client_kwargs: dict[str, t.Any] = {}
     if client_name is not None:
-        client_kwargs["client_info"] = mcp.types.Implementation(
+        client_kwargs["client_info"] = mcp_types.Implementation(
             name=client_name, version="9.9"
         )