MCP tool name exceeds 64 character limit with UUID-based server IDs

Description

When using MCP connectors from Claude.ai (cloud-based integrations like Slack, Notion), the tool names exceed the 64 character API limit, causing API errors.

Error Message

API Error: 400 {"type":"error","error":
{"type":"invalid_request_error","message":"messages.2.content.0.tool_result.content.0.tool_reference.tool_name: String should have at most 64 characters"},"request_id":"req_011CXWWw5WiR2TpNWUDMzcdK"}

Root Cause

MCP connectors from Claude.ai use UUID-based server IDs, resulting in tool names like:

mcp__5b72495d-5e79-4584-8012-2bb5911c8de1__slack_search_public_and_private

This tool name is 72 characters, exceeding the 64 character limit by 8 characters.

Affected Tools

Any MCP connector with longer tool names combined with UUID server IDs:

• mcp__5b72495d-....__slack_search_public_and_private (72 chars)
• mcp__14607fe6-....__notion-get-comments
• mcp__2eca0918-....__getJiraIssueTypeMetaWithFields

Expected Behavior

MCP tool names should stay within the 64 character limit.

Suggested Fixes

1. Use shorter server identifiers instead of full UUIDs (e.g., first 8 chars: mcp__5b72495d__slack_search...)
2. Use hash-based short IDs
3. Allow users to set custom short aliases for MCP connectors

Workaround

Currently, users can work around this by setting up local MCP servers in ~/.claude/settings.local.json with short server names instead of using Claude.ai MCP connectors.

Environment

• Claude Code CLI
• MCP connectors configured via Claude.ai web interface