API Error: MCP tool names from plugins can exceed 64-character limit

Description

MCP tools from plugins can generate tool names that exceed the Anthropic API's 64-character limit for tool_name fields, causing API validation errors.

Error Message

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.63.content.0.tool_result.content.0.tool_reference.tool_name: String should have at most 64 characters"}}

Root Cause

The MCP tool naming convention for plugins follows this pattern:

mcp__plugin_{plugin-name}_{server-name}__{tool-name}

For plugins with moderately long names, this can exceed 64 characters. Example:

mcp__plugin_jenkins-mcp-plugin_jenkins__jenkins_get_build_console

This is 65 characters - one over the API limit.

Reproduction Steps

1. Install a plugin with a long name (e.g., jenkins-mcp-plugin) that has an MCP server
2. Use ToolSearch to find tools from that plugin
3. Attempt to use one of the returned tools
4. The API returns a 400 error because the tool name exceeds 64 characters

Expected Behavior

Tool names should always be within the API's 64-character limit, regardless of plugin or server naming.

Suggested Fix

Options to consider:

1. Shorten the prefix scheme (e.g., mcp_p_{plugin}_{server}__{tool})
2. Hash or truncate long segments while maintaining uniqueness
3. Validate tool name length during plugin loading and warn/error if exceeded

Environment

• Claude Code CLI
• Plugin: jenkins-mcp-plugin (custom MCP server plugin)
• The issue affects any plugin where plugin-name + server-name + tool-name creates a combined length > 64 chars