fix: MCP error -32603: Cannot read properties of undefined (reading 'toLowerCase')

[caizhiqiangzeyuan]

fix the bug 2044

Description

1.Safer Query Handling: Since query is typed as string, we skip unnecessary safety checks and directly process it with lowerQuery = query.trim().toLowerCase()

2.Extracted Matching Logic: Created reusable checkMatch helper that encapsulates: Type checking (typeof text === 'string') Normalization (trim()+toLowerCase()) Search logic (includes())

3.Performance Optimizations: Pre-computes lowerQuery once instead of per-filter iteration Eliminates repeated arrow function creation in array operations

4.Improved Readability: Flattened nested conditions Clear separation of concerns between filtering steps More descriptive variable names

Server Details

• Server: The search_nodes function in the MCP memory server fails with a JavaScript error when attempting to search the knowledge graph. The error indicates that the search function is trying to call .toLowerCase() on an undefined value without proper input validation.
• Changes to: Map to safe lower case

Motivation and Context

bug address

How Has This Been Tested?

Yes, Cursor and Claude.

Breaking Changes

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Documentation update

Checklist

• [x] I have read the MCP Protocol Documentation
• [x] My changes follows MCP security best practices
• [ ] I have updated the server's README accordingly
• [x] I have tested this with an LLM client
• [x] My code follows the repository's style guidelines
• [x] New and existing tests pass locally
• [x] I have added appropriate error handling
• [ ] I have documented all environment variables and configuration options

Additional context