Test Fixes for draft SEP-1319 changes - modelcontextprotocol/modelcontextprotocol#1770 needed first #1084

ccreighton-apptio · 2025-11-05T22:09:27Z

SEP-1319 breaks out params into individual types. Arbitrary parameters were fixed for several types in the process.

Motivation and Context

Tests are failing

How Has This Been Tested?

Tests are passing

Breaking Changes

From draft schema changes, yes

Types of changes

Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to change)
Documentation update

Checklist

I have read the MCP Documentation
My code follows the repository's style guidelines
New and existing tests pass locally
I have added appropriate error handling
I have added or updated documentation as needed

Additional context

This is incomplete - modelcontextprotocol/modelcontextprotocol#1770 must be merged first and then the fetch:spec-types change must be reverted.

This does not implement SEP-1319 here, only:

Adjusts types for the breaking changes (removal of arbitrary params)
Ignores the new types

If there is a desire to implement SEP-1319 here, the params types would need separate definitions and test coverage. I do not intend to complete that refactor. These changes will unblock the current build failures pending a complete implementation.

ccreighton-apptio

The 18 new types have been ignored in tests, rather than implementing SEP-1319 in this PR.

ccreighton-apptio · 2025-11-05T22:09:59Z

package.json

    ],
    "scripts": {
-        "fetch:spec-types": "curl -o spec.types.ts https://raw.githubusercontent.com/modelcontextprotocol/modelcontextprotocol/refs/heads/main/schema/draft/schema.ts",
+        "fetch:spec-types": "curl -o spec.types.ts https://raw.githubusercontent.com/ccreighton-apptio/modelcontextprotocol/refs/heads/fix/tool-call-arguments-regression/schema/draft/schema.ts",


This is a temporary change until modelcontextprotocol/modelcontextprotocol#1770 is merged to fix a regression.

ccreighton-apptio · 2025-11-05T22:10:28Z

src/spec.types.test.ts

        expect(specTypes).toContain('JSONRPCNotification');
        expect(specTypes).toContain('ElicitResult');
-        expect(specTypes).toHaveLength(94);
+        expect(specTypes).toHaveLength(112);


New tests and types are still needed... tests currently fail without them.

ccreighton-apptio · 2025-11-05T22:11:19Z

src/types.ts

-const BaseRequestParamsSchema = z
-    .object({
-        _meta: z.optional(RequestMetaSchema)
-    })
-    .passthrough();
+const BaseRequestParamsSchema = z.object({
+    _meta: z.optional(RequestMetaSchema)
+});


passthrough() behavior on base params has been removed from the spec.

ccreighton-apptio · 2025-11-05T22:12:50Z

src/types.ts

 export const RequestSchema = z.object({
    method: z.string(),
-    params: z.optional(BaseRequestParamsSchema)
+    params: z.optional(z.record(z.any()))
 });


base classes in the spec enable new extensions of RequestSchema by NOT using the broken-out types in their param definitions

ccreighton-apptio · 2025-11-05T22:14:02Z

src/types.ts

-        _meta: z.optional(z.object({}).passthrough())
-    })
-    .passthrough();
+const NotificationsMetaSchema = z.object({}).passthrough();


Not sure if splitting this out will be necessary in the end, but was following the style set by having RequestMetaSchema defined separately from BaseRequestParamsSchema

ccreighton-apptio · 2025-11-05T22:14:28Z

src/types.ts

 export const NotificationSchema = z.object({
    method: z.string(),
-    params: z.optional(BaseNotificationParamsSchema)
+    params: z.optional(z.record(z.any()))
 });


base classes in the spec enable new extensions of NotificationSchema by NOT using the broken-out types in their param definitions

ccreighton-apptio · 2025-11-05T22:15:21Z

src/types.ts

 export const InitializedNotificationSchema = NotificationSchema.extend({
-    method: z.literal('notifications/initialized')
+    method: z.literal('notifications/initialized'),
+    params: z.optional(BaseNotificationParamsSchema)
 });


Individual types are now where Base params are applied, where previously they were included from extending

ccreighton-apptio · 2025-11-05T22:15:57Z

src/types.ts

-export const ProgressSchema = z
-    .object({
-        /**
-         * The progress thus far. This should increase every time progress is made, even if the total is unknown.
-         */
-        progress: z.number(),
-        /**
-         * Total number of items to process (or total progress required), if known.
-         */
-        total: z.optional(z.number()),
-        /**
-         * An optional message describing the current progress.
-         */
-        message: z.optional(z.string())
-    })
-    .passthrough();
+export const ProgressSchema = z.object({
+    /**
+     * The progress thus far. This should increase every time progress is made, even if the total is unknown.
+     */
+    progress: z.number(),
+    /**
+     * Total number of items to process (or total progress required), if known.
+     */
+    total: z.optional(z.number()),
+    /**
+     * An optional message describing the current progress.
+     */
+    message: z.optional(z.string())
+});


this is from lint:fix

E: Actually, looks like I removed a passthrough() here (resulting in the lint change) because it causes ServerNotification not to be spec-compliant.

ccreighton-apptio · 2025-11-05T23:02:29Z

src/spec.types.test.ts

+    // Params types are not exported as standalone types in the SDK (they're inferred from Zod schemas):
+    'RequestParams',
+    'NotificationParams',
+    'CancelledNotificationParams',
+    'InitializeRequestParams',
+    'ProgressNotificationParams',
+    'PaginatedRequestParams',
+    'ResourceRequestParams',
+    'ReadResourceRequestParams',
+    'SubscribeRequestParams',
+    'UnsubscribeRequestParams',
+    'SetLevelRequestParams',
+    'GetPromptRequestParams',
+    'CompleteRequestParams',
+    'CallToolRequestParams',
+    'CreateMessageRequestParams',
+    'LoggingMessageNotificationParams',
+    'ResourceUpdatedNotificationParams',
+    'ElicitRequestParams',
+


Alternatively, if the path @ksinder was taking is acceptable, then the only pending change here is getting modelcontextprotocol/modelcontextprotocol#1770 merged so that the fetch:spec-types change can be reverted.

KKonstantinov · 2025-11-07T00:08:42Z

Hi, FYI have opened #1086, which resolves the spec issues (apart from modelcontextprotocol/modelcontextprotocol#1770). However, it contains removal of .passthrough() as well and needs review/acceptance. Depending on decisions, could open it without the passthrough removals.

ccreighton-apptio · 2025-11-07T01:08:33Z

Cool! At a glance, that looks like a much more complete implementation of the SEP. I can't speak to the desires of the typescript-sdk maintainers, but note that in this PR I've only removed passthrough behavior from the specific places it needed to be to comply with the removal of passthrough behavior in the draft spec.

package.json

Partial fixes for SEP-1319 changes

a752696

ccreighton-apptio requested a review from a team as a code owner November 5, 2025 22:09

ccreighton-apptio commented Nov 5, 2025

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ccreighton-apptio mentioned this pull request Nov 5, 2025

SEP-1319: Decouple Request Payloads + _meta erasure fix (#1284) + "breaking" arbitrary params fix modelcontextprotocol/modelcontextprotocol#1692

Merged

9 tasks

In the meantime, steal the list of param types from @ksinder

50e3f3a

ccreighton-apptio commented Nov 5, 2025

View reviewed changes

ccreighton-apptio changed the title ~~Partial fixes for SEP-1319 changes~~ Test Fixes for draft SEP-1319 changes - modelcontextprotocol/modelcontextprotocol#1770 needed first Nov 6, 2025

pcarleton reviewed Nov 7, 2025

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Update package.json

7411b91

ccreighton-apptio closed this Nov 7, 2025

Test Fixes for draft SEP-1319 changes - modelcontextprotocol/modelcontextprotocol#1770 needed first #1084

Test Fixes for draft SEP-1319 changes - modelcontextprotocol/modelcontextprotocol#1770 needed first #1084

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KKonstantinov commented Nov 7, 2025

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ccreighton-apptio commented Nov 7, 2025

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