Resource not found (-32602, formerly -32002)

What it means

The client asked to read a resource URI the server does not know. We read greeting://nope from servers that only have greeting://hello:

Server	Error
TypeScript SDK v2 2.4.0	{"code":-32602,"message":"Resource not found: greeting://nope","data":{"uri":"greeting://nope"}}
TypeScript SDK v1 1.32.2	MCP error -32602: Resource greeting://nope not found
Python SDK 2.3.0	{"code":-32602,"message":"Unknown resource: greeting://nope","data":{"uri":"greeting://nope"}}

The 2025-11-25 specification recommended -32002 for this case. The 2026-07-28 changelog changes it to -32602 (Invalid Params) “to align with JSON-RPC specification”. All three current SDKs we tested already return -32602, on both 2025 and 2026 connections.

The URI is not one the server serves

• Compare the URI character by character with resources/list or resources/templates/list. Schemes, trailing slashes and percent-encoding matter.
• For a template such as file:///{path}, check that the server’s handler accepts the value the client filled in.
• A URI the model made up, rather than one from the list, is common. Describe resources clearly so the host offers real ones.

Your code checks for -32002

Client code written for 2025 that treats only -32002 as “not found” misses the new code and may show a generic error or retry. Check for both while servers of both generations are around, and prefer the error’s data.uri over parsing the message.

Related

• Tool … not found
• Migrating from 2025-11-25 to 2026-07-28