[TRACKING] non compliance with SEP-986 / tool name validation

[mattzcarey]

Using this issue to track non compliance by LLM providers / MCP Clients with tool name spec validation.

For context this is the current spec:

- Tool names SHOULD be between 1 and 128 characters in length (inclusive).
- Tool names SHOULD be considered case-sensitive.
- The following SHOULD be the only allowed characters: uppercase and lowercase ASCII letters (A-Z, a-z), digits (0-9), underscore (_), hyphen (-), and dot (.)
- Tool names SHOULD NOT contain spaces, commas, or other special characters.
- Tool names SHOULD be unique within a server.
- Example valid tool names: getUser, DATA_EXPORT_v2, admin.tools.list

Please report compliance issues below.

[drewbuschhorn]

Thanks @mattzcarey. I think the spec documentation in https://github.com/modelcontextprotocol/modelcontextprotocol/blob/main/docs/specification/2025-11-25/server/tools.mdx#tool-names:

Tool Names
Tool names SHOULD be between 1 and 128 characters in length (inclusive).
Tool names SHOULD be considered case-sensitive.
The following SHOULD be the only allowed characters: uppercase and lowercase ASCII letters (A-Z, a-z), digits (0-9), underscore (_), hyphen (-), and dot (.)
Tool names SHOULD NOT contain spaces, commas, or other special characters.
Tool names SHOULD be unique within a server.
Example valid tool names:
getUser
DATA_EXPORT_v2
admin.tools.list

doesn't match the actual final issue of SEP-986 from @kentcdodds:

Tool names SHOULD be between 1 and 64 characters in length (inclusive).
Tool names are case-sensitive.
Allowed characters: uppercase and lowercase ASCII letters (A-Z, a-z), digits
(0-9), underscore (_), dash (-), dot (.), and forward slash (/).
Tool names SHOULD NOT contain spaces, commas, or other special characters.
Tool names SHOULD be unique within their namespace.
Example valid tool names:
getUser
user-profile/update
DATA_EXPORT_v2
admin.tools.list

It looks like the SEP-986 adjustments occurred on:

• [+]1–64[/+][-] 1–128[/-] , 2025-09-29
• [+]characters, underscores (_), dashes (-), dots (.), and forward slashes (/).[/+][-] unique within their namespace. This change aims to improve clarity, 2025-07-16

and SEP-986 was moved to final on 2025-10-29.

It looks like on Oct 14, modelcontextprotocol/modelcontextprotocol#1603 was created, but didn't have the changes made to the proposal's definition in the issue ticket.

Maybe it's just a case of changes being made to SEP-986 (#986) not being propagated to alexhancock:SEP-986 (branch), @kentcdodds?