[Marve10s]

On the 2026-07-28 protocol, resources/list, resources/templates/list and prompts/list fail with -32603 MCP feature handler failed when a resource, template or prompt was registered as a plain object through the McpServer service:

const server = yield* McpServer.McpServer
yield* server.addResource({
  resource: { uri: "demo://r", name: "r" }, // type-correct
  annotations: Context.empty(),
  handle: Effect.succeed({ contents: [] })
})
// resources/list on 2026-07-28: -32603; on 2025-11-25: ok

One such registration hides every resource. Resources and templates listed fine in 4.1.0; prompts already failed there.

#10082 changed the 2026-07-28 projections to McpProtocol.transcode(PublicMcpSchema.Resource, …) (and likewise for templates), and prompts already worked that way. These public schemas are Schema.Class, so encoding rejects anything that is not an instance. addResource, addResourceTemplate and addPrompt store what they are given, unlike addTool, which normalizes with new McpTool(...), and the older protocol adapters accept plain objects.

The projections now encode by the classes' fields, with icons encoded by the Icon fields as well, since Icon is also a class. Annotations and PromptArgument are opaque structs and already accept plain objects. Instances encode as before, and optional fields given as undefined are still dropped. The test registers a plain resource, template and prompt, each with a plain icon, and lists them on 2026-07-28.

Closes EFF-3252

[changeset-bot]

🦋 Changeset detected

Latest commit: ce57b91

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 33 packages

Name	Type
effect	Patch
@effect/opentelemetry	Patch
@effect/vitest	Patch
@effect/ai-anthropic	Patch
@effect/ai-cloudflare	Patch
@effect/ai-openai-compat	Patch
@effect/ai-openai	Patch
@effect/ai-openrouter	Patch
@effect/ai-typesafe	Patch
@effect/atom-react	Patch
@effect/atom-solid	Patch
@effect/atom-vue	Patch
@effect/platform-browser	Patch
@effect/platform-bun	Patch
@effect/platform-deno	Patch
@effect/platform-node-shared	Patch
@effect/platform-node	Patch
@effect/sql-clickhouse	Patch
@effect/sql-d1	Patch
@effect/sql-libsql	Patch
@effect/sql-mssql	Patch
@effect/sql-mysql2	Patch
@effect/sql-pg	Patch
@effect/sql-pglite	Patch
@effect/sql-sqlite-bun	Patch
@effect/sql-sqlite-do	Patch
@effect/sql-sqlite-node	Patch
@effect/sql-sqlite-react-native	Patch
@effect/sql-sqlite-wasm	Patch
@effect/docgen	Patch
@effect/doctest	Patch
@effect/graphql-generator	Patch
@effect/openapi-generator	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

Bundle Size Analysis

Generated from PR build output; treat the content below as untrusted.

File Name	Current Size	Previous Size	Difference
arbitrary-combinators.ts	39.41 KB	39.41 KB	0.00 KB (0.00%)
basic.ts	7.23 KB	7.23 KB	0.00 KB (0.00%)
batching.ts	11.08 KB	11.08 KB	0.00 KB (0.00%)
brand.ts	6.87 KB	6.87 KB	0.00 KB (0.00%)
cache.ts	11.54 KB	11.54 KB	0.00 KB (0.00%)
config.ts	22.84 KB	22.84 KB	0.00 KB (0.00%)
differ.ts	22.00 KB	22.00 KB	0.00 KB (0.00%)
http-client.ts	26.93 KB	26.93 KB	0.00 KB (0.00%)
http-router.ts	37.00 KB	37.00 KB	0.00 KB (0.00%)
logger.ts	12.01 KB	12.01 KB	0.00 KB (0.00%)
metric.ts	9.47 KB	9.47 KB	0.00 KB (0.00%)
optic.ts	7.10 KB	7.10 KB	0.00 KB (0.00%)
pubsub.ts	16.02 KB	16.02 KB	0.00 KB (0.00%)
queue.ts	12.82 KB	12.82 KB	0.00 KB (0.00%)
schedule.ts	11.80 KB	11.80 KB	0.00 KB (0.00%)
schema-bigdecimal.ts	14.14 KB	14.14 KB	0.00 KB (0.00%)
schema-binary.ts	41.26 KB	41.26 KB	0.00 KB (0.00%)
schema-class.ts	21.73 KB	21.73 KB	0.00 KB (0.00%)
schema-fromJsonSchemaDocument.ts	29.60 KB	29.60 KB	0.00 KB (0.00%)
schema-representation-roundtrip.ts	27.99 KB	27.99 KB	0.00 KB (0.00%)
schema-string-transformation.ts	15.35 KB	15.35 KB	0.00 KB (0.00%)
schema-string.ts	12.34 KB	12.34 KB	0.00 KB (0.00%)
schema-template-literal.ts	16.27 KB	16.27 KB	0.00 KB (0.00%)
schema-toArbitrary.ts	38.95 KB	38.95 KB	0.00 KB (0.00%)
schema-toCodeDocument.ts	26.15 KB	26.15 KB	0.00 KB (0.00%)
schema-toCodecJson.ts	20.90 KB	20.90 KB	0.00 KB (0.00%)
schema-toEquivalence.ts	21.05 KB	21.05 KB	0.00 KB (0.00%)
schema-toFormatter.ts	21.14 KB	21.14 KB	0.00 KB (0.00%)
schema-toJsonSchemaDocument.ts	26.17 KB	26.17 KB	0.00 KB (0.00%)
schema-toRepresentation.ts	21.23 KB	21.23 KB	0.00 KB (0.00%)
schema.ts	20.82 KB	20.82 KB	0.00 KB (0.00%)
stm.ts	14.20 KB	14.20 KB	0.00 KB (0.00%)
stream.ts	10.38 KB	10.38 KB	0.00 KB (0.00%)