Make the per-version wire packages private (mcp_types._v*)

.github/workflows/shared.yml

@@ -51,7 +51,7 @@ jobs:
       - name: mcp-types installs and imports standalone
         run: |
           uv run --isolated --no-project --with ./src/mcp-types python -c \
-            "import mcp_types, mcp_types.jsonrpc, mcp_types.methods, mcp_types.version, mcp_types.v2025_11_25, mcp_types.v2026_07_28"
+            "import mcp_types, mcp_types.jsonrpc, mcp_types.methods, mcp_types.version, mcp_types._v2025_11_25, mcp_types._v2026_07_28"
 
   test:
     name: test (${{ matrix.python-version }}, ${{ matrix.dep-resolution.name }}, ${{ matrix.os }})

docs/migration.md

@@ -175,6 +175,11 @@ continues to re-export the type names at the top level, so `from mcp import Tool
 unchanged. Only the `mcp.types` submodule and `mcp.shared.version` were removed. The
 package's API reference is at [`mcp_types`](api/mcp_types/index.md).
 
+The supported import surface is `mcp_types`, `mcp_types.jsonrpc`, `mcp_types.methods`, and
+`mcp_types.version`. Underscore-prefixed submodules (`mcp_types._types`, and the generated
+per-protocol-version packages `mcp_types._v2025_11_25` / `mcp_types._v2026_07_28`) are internal
+validators with unstable class names; don't import from them.
+
 **Why:** keeping the wire types in their own package lets tooling and lightweight clients
 depend on the protocol schema without pulling in `httpx2`, `starlette`, `uvicorn`, and the
 rest of the server/transport stack.

pyproject.toml

@@ -218,7 +218,7 @@ max-complexity = 24 # Default is 10
 [tool.ruff.lint.per-file-ignores]
 "__init__.py" = ["F401"]
 # Generated by scripts/gen_surface_types.py: raw datamodel-codegen output (TID251 lifts the repo-wide RootModel ban for these generated validators).
-"src/mcp-types/mcp_types/v*/__init__.py" = ["D212", "E501", "I001", "TID251", "UP007", "UP037"]
+"src/mcp-types/mcp_types/_v*/__init__.py" = ["D212", "E501", "I001", "TID251", "UP007", "UP037"]
 "tests/server/mcpserver/test_func_metadata.py" = ["E501"]
 "tests/shared/test_progress_notifications.py" = ["PLW0603"]
 

scripts/gen_surface_types.py

@@ -1,8 +1,9 @@
 """Regenerate the per-version wire-shape surface packages from vendored schemas.
 
 Runs `datamodel-code-generator` over each `schema/PINNED.json` entry and
-writes the result to `src/mcp-types/mcp_types/v<version>/__init__.py` with only the
-fixes the raw output needs: a small JSON pre-patch for the known
+writes the result to `src/mcp-types/mcp_types/_v<version>/__init__.py` (the
+underscore marks these as internal validators, not public API) with only
+the fixes the raw output needs: a small JSON pre-patch for the known
 `number`-as-`integer` schema.json defect, a header, full URLs for the spec's
 site-absolute doc links, and per-version epilogue aliases. Run with
 `uv run --frozen --group codegen python scripts/gen_surface_types.py [--check]`.
@@ -270,7 +271,7 @@
 
     drift = False
     for entry in load_pinned():
-        target = TYPES_DIR / ("v" + entry["protocol_version"].replace("-", "_")) / "__init__.py"
+        target = TYPES_DIR / ("_v" + entry["protocol_version"].replace("-", "_")) / "__init__.py"
         candidate = build(entry)
         if not args.check:
             target.parent.mkdir(parents=True, exist_ok=True)

src/mcp-types/mcp_types/_types.py

@@ -3,7 +3,7 @@
 One model per protocol construct, carrying every field from every supported
 protocol version, so application code sees a single set of types regardless of
 the negotiated version. Per-field docstrings note version availability. The
-`mcp_types.v*` surface packages carry the schema-exact wire shapes.
+`mcp_types._v*` surface packages carry the schema-exact wire shapes.
 """
 
 from __future__ import annotations

src/mcp-types/mcp_types/_wire_base.py

@@ -1,4 +1,4 @@
-"""Shared pydantic base for the generated `mcp_types.v*` wire-shape packages."""
+"""Shared pydantic base for the generated `mcp_types._v*` wire-shape packages."""
 
 from pydantic import BaseModel, ConfigDict
 

src/mcp-types/mcp_types/methods.py

@@ -1,6 +1,6 @@
 """Per-version method maps and parse/serialize functions for MCP traffic.
 
-This module is supported public API; the `mcp_types.v*` packages it draws on
+This module is supported public API; the `mcp_types._v*` packages it draws on
 are internal validators and not for direct import.
 
 Surface maps key `(method, version)` to per-version wire types (key absence is
@@ -18,8 +18,8 @@
 from pydantic import BaseModel, TypeAdapter
 
 import mcp_types as types
-import mcp_types.v2025_11_25 as v2025
-import mcp_types.v2026_07_28 as v2026
+import mcp_types._v2025_11_25 as v2025
+import mcp_types._v2026_07_28 as v2026
 from mcp_types.version import KNOWN_PROTOCOL_VERSIONS
 
 __all__ = [

src/mcp/server/elicitation.py

@@ -7,7 +7,7 @@
 from mcp_types import RequestId
 
 # Internal surface package; imported as the gate's source of truth for spec-valid property schemas.
-from mcp_types.v2025_11_25 import PrimitiveSchemaDefinition
+from mcp_types._v2025_11_25 import PrimitiveSchemaDefinition
 from pydantic import BaseModel, ValidationError
 from pydantic.json_schema import GenerateJsonSchema, JsonSchemaValue
 from pydantic_core import core_schema

tests/types/test_methods.py

@@ -6,8 +6,8 @@
 from typing import Any, get_args
 
 import mcp_types as types
-import mcp_types.v2025_11_25 as v2025
-import mcp_types.v2026_07_28 as v2026
+import mcp_types._v2025_11_25 as v2025
+import mcp_types._v2026_07_28 as v2026
 import pydantic
 import pytest
 from mcp_types import methods
@@ -295,11 +295,11 @@
 
 # Pre-2026 versions share the 2025-11-25 surface package.
 PACKAGE_BY_VERSION = {
-    "2024-11-05": "mcp_types.v2025_11_25",
-    "2025-03-26": "mcp_types.v2025_11_25",
-    "2025-06-18": "mcp_types.v2025_11_25",
-    "2025-11-25": "mcp_types.v2025_11_25",
-    "2026-07-28": "mcp_types.v2026_07_28",
+    "2024-11-05": "mcp_types._v2025_11_25",
+    "2025-03-26": "mcp_types._v2025_11_25",
+    "2025-06-18": "mcp_types._v2025_11_25",
+    "2025-11-25": "mcp_types._v2025_11_25",
+    "2026-07-28": "mcp_types._v2026_07_28",
 }
 
 # The reserved `params._meta` entries the 2026 surface accepts on every request.

tests/types/test_parity.py

@@ -7,8 +7,8 @@
 
 import mcp_types as monolith
 import mcp_types._types as _types
-import mcp_types.v2025_11_25 as v2025_11_25
-import mcp_types.v2026_07_28 as v2026_07_28
+import mcp_types._v2025_11_25 as v2025_11_25
+import mcp_types._v2026_07_28 as v2026_07_28
 import pytest
 from pydantic import BaseModel
 
@@ -19,116 +19,116 @@
 
 # Surface classes whose monolith counterpart has a different name (key: "<surface_tail>.<ClassName>").
 NAME_MAP: dict[str, type[BaseModel]] = {
-    # v2025_11_25
-    "v2025_11_25.Argument": monolith.CompletionArgument,
-    "v2025_11_25.Context": monolith.CompletionContext,
-    "v2025_11_25.Data": monolith.ElicitationRequiredErrorData,
-    "v2025_11_25.Elicitation": monolith.ElicitationCapability,
-    "v2025_11_25.Elicitation1": monolith.TasksElicitationCapability,
-    "v2025_11_25.ElicitationCompleteNotification": monolith.ElicitCompleteNotification,
-    "v2025_11_25.Params": monolith.CancelTaskRequestParams,
-    "v2025_11_25.Params1": monolith.ElicitCompleteNotificationParams,
-    "v2025_11_25.Params2": monolith.GetTaskPayloadRequestParams,
-    "v2025_11_25.Params3": monolith.GetTaskRequestParams,
-    "v2025_11_25.Error": monolith.ErrorData,
-    "v2025_11_25.JSONRPCErrorResponse": monolith.JSONRPCError,
-    "v2025_11_25.JSONRPCResultResponse": monolith.JSONRPCResponse,
-    "v2025_11_25.Prompts": monolith.PromptsCapability,
-    "v2025_11_25.Requests": monolith.ClientTasksRequestsCapability,
-    "v2025_11_25.Requests1": monolith.ServerTasksRequestsCapability,
-    "v2025_11_25.Resources": monolith.ResourcesCapability,
-    "v2025_11_25.Roots": monolith.RootsCapability,
-    "v2025_11_25.Sampling": monolith.SamplingCapability,
-    "v2025_11_25.Sampling1": monolith.TasksSamplingCapability,
-    "v2025_11_25.Tasks": monolith.ClientTasksCapability,
-    "v2025_11_25.Tasks1": monolith.ServerTasksCapability,
-    "v2025_11_25.Tools": monolith.TasksToolsCapability,
-    "v2025_11_25.Tools1": monolith.ToolsCapability,
-    # v2026_07_28
-    "v2026_07_28.Argument": monolith.CompletionArgument,
-    "v2026_07_28.Context": monolith.CompletionContext,
-    "v2026_07_28.Data": monolith.MissingRequiredClientCapabilityErrorData,
-    "v2026_07_28.Data1": monolith.UnsupportedProtocolVersionErrorData,
-    "v2026_07_28.Elicitation": monolith.ElicitationCapability,
-    "v2026_07_28.Error": monolith.ErrorData,
-    "v2026_07_28.JSONRPCErrorResponse": monolith.JSONRPCError,
-    "v2026_07_28.JSONRPCResultResponse": monolith.JSONRPCResponse,
-    "v2026_07_28.Prompts": monolith.PromptsCapability,
-    "v2026_07_28.Resources": monolith.ResourcesCapability,
-    "v2026_07_28.Sampling": monolith.SamplingCapability,
-    "v2026_07_28.Tools": monolith.ToolsCapability,
+    # _v2025_11_25
+    "_v2025_11_25.Argument": monolith.CompletionArgument,
+    "_v2025_11_25.Context": monolith.CompletionContext,
+    "_v2025_11_25.Data": monolith.ElicitationRequiredErrorData,
+    "_v2025_11_25.Elicitation": monolith.ElicitationCapability,
+    "_v2025_11_25.Elicitation1": monolith.TasksElicitationCapability,
+    "_v2025_11_25.ElicitationCompleteNotification": monolith.ElicitCompleteNotification,
+    "_v2025_11_25.Params": monolith.CancelTaskRequestParams,
+    "_v2025_11_25.Params1": monolith.ElicitCompleteNotificationParams,
+    "_v2025_11_25.Params2": monolith.GetTaskPayloadRequestParams,
+    "_v2025_11_25.Params3": monolith.GetTaskRequestParams,
+    "_v2025_11_25.Error": monolith.ErrorData,
+    "_v2025_11_25.JSONRPCErrorResponse": monolith.JSONRPCError,
+    "_v2025_11_25.JSONRPCResultResponse": monolith.JSONRPCResponse,
+    "_v2025_11_25.Prompts": monolith.PromptsCapability,
+    "_v2025_11_25.Requests": monolith.ClientTasksRequestsCapability,
+    "_v2025_11_25.Requests1": monolith.ServerTasksRequestsCapability,
+    "_v2025_11_25.Resources": monolith.ResourcesCapability,
+    "_v2025_11_25.Roots": monolith.RootsCapability,
+    "_v2025_11_25.Sampling": monolith.SamplingCapability,
+    "_v2025_11_25.Sampling1": monolith.TasksSamplingCapability,
+    "_v2025_11_25.Tasks": monolith.ClientTasksCapability,
+    "_v2025_11_25.Tasks1": monolith.ServerTasksCapability,
+    "_v2025_11_25.Tools": monolith.TasksToolsCapability,
+    "_v2025_11_25.Tools1": monolith.ToolsCapability,
+    # _v2026_07_28
+    "_v2026_07_28.Argument": monolith.CompletionArgument,
+    "_v2026_07_28.Context": monolith.CompletionContext,
+    "_v2026_07_28.Data": monolith.MissingRequiredClientCapabilityErrorData,
+    "_v2026_07_28.Data1": monolith.UnsupportedProtocolVersionErrorData,
+    "_v2026_07_28.Elicitation": monolith.ElicitationCapability,
+    "_v2026_07_28.Error": monolith.ErrorData,
+    "_v2026_07_28.JSONRPCErrorResponse": monolith.JSONRPCError,
+    "_v2026_07_28.JSONRPCResultResponse": monolith.JSONRPCResponse,
+    "_v2026_07_28.Prompts": monolith.PromptsCapability,
+    "_v2026_07_28.Resources": monolith.ResourcesCapability,
+    "_v2026_07_28.Sampling": monolith.SamplingCapability,
+    "_v2026_07_28.Tools": monolith.ToolsCapability,
 }
 
 # Surface classes with no monolith equivalent (envelope wrappers, JSON-Schema fragments modelled as `dict`).
 SKIP: frozenset[str] = frozenset(
     {
-        # v2025_11_25
-        "v2025_11_25.AnyOfItem",
-        "v2025_11_25.BooleanSchema",
-        "v2025_11_25.Error1",
-        "v2025_11_25.Icons",
-        "v2025_11_25.InputSchema",
-        "v2025_11_25.Items",
-        "v2025_11_25.Items1",
-        "v2025_11_25.LegacyTitledEnumSchema",
-        "v2025_11_25.Meta",
-        "v2025_11_25.NumberSchema",
-        "v2025_11_25.OneOfItem",
-        "v2025_11_25.OutputSchema",
-        "v2025_11_25.RequestedSchema",
-        "v2025_11_25.ResourceRequestParams",
-        "v2025_11_25.StringSchema",
-        "v2025_11_25.TaskAugmentedRequestParams",
-        "v2025_11_25.TitledMultiSelectEnumSchema",
-        "v2025_11_25.TitledSingleSelectEnumSchema",
-        "v2025_11_25.URLElicitationRequiredError",
-        "v2025_11_25.UntitledMultiSelectEnumSchema",
-        "v2025_11_25.UntitledSingleSelectEnumSchema",
-        # v2026_07_28
-        "v2026_07_28.AnyOfItem",
-        "v2026_07_28.BooleanSchema",
-        "v2026_07_28.CallToolResultResponse",
-        "v2026_07_28.ClientNotification",
-        "v2026_07_28.CompleteResultResponse",
-        "v2026_07_28.DiscoverResultResponse",
-        "v2026_07_28.Error1",
-        "v2026_07_28.Error2",
-        "v2026_07_28.Error3",
-        "v2026_07_28.GetPromptResultResponse",
-        "v2026_07_28.HeaderMismatchError",
-        "v2026_07_28.Icons",
-        "v2026_07_28.InputSchema",
-        "v2026_07_28.InternalError",
-        "v2026_07_28.InvalidParamsError",
-        "v2026_07_28.InvalidRequestError",
-        "v2026_07_28.Items",
-        "v2026_07_28.Items1",
-        "v2026_07_28.LegacyTitledEnumSchema",
-        "v2026_07_28.ListPromptsResultResponse",
-        "v2026_07_28.ListResourceTemplatesResultResponse",
-        "v2026_07_28.ListResourcesResultResponse",
-        "v2026_07_28.ListToolsResultResponse",
-        "v2026_07_28.MetaObject",
-        "v2026_07_28.MethodNotFoundError",
-        "v2026_07_28.MissingRequiredClientCapabilityError",
-        "v2026_07_28.NotificationMetaObject",
-        "v2026_07_28.NumberSchema",
-        "v2026_07_28.OneOfItem",
-        "v2026_07_28.OutputSchema",
-        "v2026_07_28.Params",
-        "v2026_07_28.ParseError",
-        "v2026_07_28.ReadResourceResultResponse",
-        "v2026_07_28.RequestMetaObject",
-        "v2026_07_28.RequestedSchema",
-        "v2026_07_28.ResourceRequestParams",
-        "v2026_07_28.ResultMetaObject",
-        "v2026_07_28.StringSchema",
-        "v2026_07_28.SubscriptionsListenResultMeta",
-        "v2026_07_28.TitledMultiSelectEnumSchema",
-        "v2026_07_28.TitledSingleSelectEnumSchema",
-        "v2026_07_28.UnsupportedProtocolVersionError",
-        "v2026_07_28.UntitledMultiSelectEnumSchema",
-        "v2026_07_28.UntitledSingleSelectEnumSchema",
+        # _v2025_11_25
+        "_v2025_11_25.AnyOfItem",
+        "_v2025_11_25.BooleanSchema",
+        "_v2025_11_25.Error1",
+        "_v2025_11_25.Icons",
+        "_v2025_11_25.InputSchema",
+        "_v2025_11_25.Items",
+        "_v2025_11_25.Items1",
+        "_v2025_11_25.LegacyTitledEnumSchema",
+        "_v2025_11_25.Meta",
+        "_v2025_11_25.NumberSchema",
+        "_v2025_11_25.OneOfItem",
+        "_v2025_11_25.OutputSchema",
+        "_v2025_11_25.RequestedSchema",
+        "_v2025_11_25.ResourceRequestParams",
+        "_v2025_11_25.StringSchema",
+        "_v2025_11_25.TaskAugmentedRequestParams",
+        "_v2025_11_25.TitledMultiSelectEnumSchema",
+        "_v2025_11_25.TitledSingleSelectEnumSchema",
+        "_v2025_11_25.URLElicitationRequiredError",
+        "_v2025_11_25.UntitledMultiSelectEnumSchema",
+        "_v2025_11_25.UntitledSingleSelectEnumSchema",
+        # _v2026_07_28
+        "_v2026_07_28.AnyOfItem",
+        "_v2026_07_28.BooleanSchema",
+        "_v2026_07_28.CallToolResultResponse",
+        "_v2026_07_28.ClientNotification",
+        "_v2026_07_28.CompleteResultResponse",
+        "_v2026_07_28.DiscoverResultResponse",
+        "_v2026_07_28.Error1",
+        "_v2026_07_28.Error2",
+        "_v2026_07_28.Error3",
+        "_v2026_07_28.GetPromptResultResponse",
+        "_v2026_07_28.HeaderMismatchError",
+        "_v2026_07_28.Icons",
+        "_v2026_07_28.InputSchema",
+        "_v2026_07_28.InternalError",
+        "_v2026_07_28.InvalidParamsError",
+        "_v2026_07_28.InvalidRequestError",
+        "_v2026_07_28.Items",
+        "_v2026_07_28.Items1",
+        "_v2026_07_28.LegacyTitledEnumSchema",
+        "_v2026_07_28.ListPromptsResultResponse",
+        "_v2026_07_28.ListResourceTemplatesResultResponse",
+        "_v2026_07_28.ListResourcesResultResponse",
+        "_v2026_07_28.ListToolsResultResponse",
+        "_v2026_07_28.MetaObject",
+        "_v2026_07_28.MethodNotFoundError",
+        "_v2026_07_28.MissingRequiredClientCapabilityError",
+        "_v2026_07_28.NotificationMetaObject",
+        "_v2026_07_28.NumberSchema",
+        "_v2026_07_28.OneOfItem",
+        "_v2026_07_28.OutputSchema",
+        "_v2026_07_28.Params",
+        "_v2026_07_28.ParseError",
+        "_v2026_07_28.ReadResourceResultResponse",
+        "_v2026_07_28.RequestMetaObject",
+        "_v2026_07_28.RequestedSchema",
+        "_v2026_07_28.ResourceRequestParams",
+        "_v2026_07_28.ResultMetaObject",
+        "_v2026_07_28.StringSchema",
+        "_v2026_07_28.SubscriptionsListenResultMeta",
+        "_v2026_07_28.TitledMultiSelectEnumSchema",
+        "_v2026_07_28.TitledSingleSelectEnumSchema",
+        "_v2026_07_28.UnsupportedProtocolVersionError",
+        "_v2026_07_28.UntitledMultiSelectEnumSchema",
+        "_v2026_07_28.UntitledSingleSelectEnumSchema",
     }
 )