spec/docs: specify tool name format SEP-986 (modelcontextprotocol#1603)

Co-authored-by: Kent C. Dodds <[email protected]>

Author: alexhancock

docs/docs/develop/build-client.mdx

@@ -392,6 +392,10 @@ When you submit a query:
    - Validate server responses
    - Be cautious with tool permissions
 
+4. **Tool Names**
+   - Tool names can be validated according to the format specified [here](/specification/draft/server/tools#tool-names)
+   - If a tool name conforms to the specified format, it should not fail validation by an MCP client
+
 ## Troubleshooting
 
 ### Server Path Issues

docs/docs/develop/build-server.mdx

@@ -59,6 +59,7 @@ Writing to stdout will corrupt the JSON-RPC messages and break your server.
 ### Best Practices
 
 1. Use a logging library that writes to stderr or files.
+1. Tool names should follow the format specified [here](/specification/draft/server/tools#tool-names).
 
 ### Quick Examples
 

docs/specification/draft/server/tools.mdx

@@ -204,6 +204,19 @@ tool annotations to be untrusted unless they come from trusted servers.
 
 </Warning>
 
+#### 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 (\_), dash (-), 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
+
 ### Tool Result
 
 Tool results may contain [**structured**](#structured-content) or **unstructured** content.