feat(mcp): support sse and streamable-http transports

src/reqstool/command.py

@@ -5,7 +5,7 @@
 import logging
 import os
 import sys
-from typing import Optional, TextIO, Union
+from typing import Literal, Optional, TextIO, Union, cast
 
 if __package__ is None or len(__package__) == 0:
     _script_dir = os.path.abspath(os.path.dirname(__file__))
@@ -360,10 +360,27 @@ class ComboRawTextandArgsDefaultUltimateHelpFormatter(
         mcp_parser = subparsers.add_parser(
             "mcp",
             help=(
-                "Start the Model Context Protocol server (stdio). "
+                "Start the Model Context Protocol server. "
                 "With no source, auto-detects the dataset from .reqstool-ai.yaml in cwd or an ancestor directory."
             ),
         )
+        mcp_parser.add_argument(
+            "--transport",
+            choices=["stdio", "sse", "streamable-http"],
+            default="stdio",
+            help="Transport to use (default: %(default)s)",
+        )
+        mcp_parser.add_argument(
+            "--host",
+            default="127.0.0.1",
+            help="Host for HTTP transports (default: %(default)s)",
+        )
+        mcp_parser.add_argument(
+            "--port",
+            type=int,
+            default=8000,
+            help="Port for HTTP transports (default: %(default)s)",
+        )
         mcp_source_subparsers = mcp_parser.add_subparsers(dest="source", required=False)
         self._add_subparsers_source(mcp_source_subparsers, include_report_options=False, include_filter_options=False)
 
@@ -511,7 +528,12 @@ def command_mcp(self, mcp_args: argparse.Namespace):
             location = self._get_initial_source(mcp_args)
 
         try:
-            start_server(location=location)
+            start_server(
+                location=location,
+                transport=cast(Literal["stdio", "sse", "streamable-http"], mcp_args.transport),
+                host=mcp_args.host,
+                port=mcp_args.port,
+            )
         except Exception as exc:
             logging.fatal("reqstool MCP server crashed: %s", exc)
             sys.exit(1)

src/reqstool/mcp/server.py

@@ -2,6 +2,7 @@
 
 
 import logging
+from typing import Literal
 
 from reqstool.common.project_session import ProjectSession
 from reqstool.common.enrichment.enricher import BUILT_IN_PRESETS, enrich_text
@@ -21,7 +22,12 @@
 logger = logging.getLogger(__name__)
 
 
-def start_server(location: LocationInterface) -> None:  # noqa: C901
+def start_server(  # noqa: C901
+    location: LocationInterface,
+    transport: Literal["stdio", "sse", "streamable-http"] = "stdio",
+    host: str = "127.0.0.1",
+    port: int = 8000,
+) -> None:
     try:
         from mcp.server.fastmcp import FastMCP
     except ImportError as exc:
@@ -39,6 +45,11 @@ def start_server(location: LocationInterface) -> None:  # noqa: C901
     urn_source_paths = session.urn_source_paths
 
     mcp = FastMCP("reqstool")
+    mcp.settings.host = host
+    mcp.settings.port = port
+    if transport == "streamable-http":
+        mcp.settings.json_response = True
+        mcp.settings.stateless_http = True
 
     @mcp.tool()
     def list_requirements(urn: str | None = None, lifecycle_state: str | None = None) -> list[dict]:
@@ -147,6 +158,7 @@ def enrich_document(content: str, preset: str) -> str:
         return enrich_text(content, repo.get_all_requirements(), repo.get_all_svcs(), repo.get_all_mvrs(), config)
 
     try:
-        mcp.run()
+        logger.info("Starting reqstool MCP server (transport=%s, host=%s, port=%s)", transport, host, port)
+        mcp.run(transport=transport)
     finally:
         session.close()