docs: fix stale docstrings and export DEFAULT_MAX_* constants

match() docstring: qualified the round-trip claim with the RFC
section 1.4 caveat that values containing their operator's separator
unencoded do not round-trip (e.g. {.ext} with 'tar.gz').

resource() decorator docstring: removed the 'or the function has
parameters' clause which commit 674783f made stale; template/static
is now decided purely by URI variables.

Added DEFAULT_MAX_TEMPLATE_LENGTH, DEFAULT_MAX_EXPRESSIONS, and
DEFAULT_MAX_URI_LENGTH to __all__ to match the stated intent that
these are part of the public API.

Moved DEFAULT_MAX_URI_LENGTH import in test file from function body
to top-level per repo convention.

Author: maxisbey

src/mcp/server/mcpserver/server.py

@@ -644,8 +644,9 @@ def resource(
         - bytes for binary content
         - other types will be converted to JSON
 
-        If the URI contains parameters (e.g. "resource://{param}") or the function
-        has parameters, it will be registered as a template resource.
+        If the URI contains parameters (e.g. "resource://{param}"), it is
+        registered as a template resource. Otherwise it is registered as a
+        static resource; function parameters on a static URI raise an error.
 
         Args:
             uri: URI for the resource (e.g. "resource://my-resource" or "resource://{param}")

src/mcp/shared/uri_template.py

@@ -41,7 +41,15 @@
 from typing import Literal, cast
 from urllib.parse import quote, unquote
 
-__all__ = ["InvalidUriTemplate", "Operator", "UriTemplate", "Variable"]
+__all__ = [
+    "DEFAULT_MAX_EXPRESSIONS",
+    "DEFAULT_MAX_TEMPLATE_LENGTH",
+    "DEFAULT_MAX_URI_LENGTH",
+    "InvalidUriTemplate",
+    "Operator",
+    "UriTemplate",
+    "Variable",
+]
 
 Operator = Literal["", "+", "#", ".", "/", ";", "?", "&"]
 
@@ -387,8 +395,12 @@ def match(self, uri: str, *, max_uri_length: int = DEFAULT_MAX_URI_LENGTH) -> di
 
         This is the inverse of :meth:`expand`. The URI is matched against
         a regex derived from the template and captured values are
-        percent-decoded. For any value ``v``, ``match(expand({k: v}))``
-        returns ``{k: v}``.
+        percent-decoded. The round-trip ``match(expand({k: v})) == {k: v}``
+        holds when ``v`` does not contain its operator's separator
+        unencoded: ``{.ext}`` with ``ext="tar.gz"`` expands to
+        ``.tar.gz`` but matches back as ``ext="tar"`` since the ``.``
+        pattern stops at the first dot. RFC 6570 §1.4 notes this is an
+        inherent reversal limitation.
 
         Matching is structural at the URI level only: a simple ``{name}``
         will not match across a literal ``/`` in the URI (the regex stops

tests/shared/test_uri_template.py

@@ -2,7 +2,7 @@
 
 import pytest
 
-from mcp.shared.uri_template import InvalidUriTemplate, UriTemplate, Variable
+from mcp.shared.uri_template import DEFAULT_MAX_URI_LENGTH, InvalidUriTemplate, UriTemplate, Variable
 
 
 def test_parse_literal_only():
@@ -567,8 +567,6 @@ def test_match_accepts_uri_within_custom_limit():
 
 
 def test_match_default_uri_length_limit():
-    from mcp.shared.uri_template import DEFAULT_MAX_URI_LENGTH
-
     t = UriTemplate.parse("{+var}")
     # Just at the limit: should match
     assert t.match("x" * DEFAULT_MAX_URI_LENGTH) is not None