Problem

When an LLM extracts relationship names containing hyphens (e.g. manages_via_low-cost_models), Neo4j throws a CypherSyntaxError because - is not a valid character in unquoted Cypher identifiers:

neo4j.exceptions.CypherSyntaxError: Invalid input '-': expected a parameter, '&', '*', ':', 'WHERE', ']', '{' or '|'
"MERGE (source)-[r:manages_via_low-cost_models]->(destination)"

Root Cause

sanitize_relationship_for_cypher() in mem0/memory/utils.py handles many special characters (/, @, !, etc.) but does not handle - (hyphen/minus).

Fix

Add "-": "_" to the character mapping in sanitize_relationship_for_cypher(), consistent with how other special characters are already handled.

Before: manages_via_low-cost_models → CypherSyntaxError
After: manages_via_low-cost_models → manages_via_low_cost_models ✅

Changes

• mem0/memory/utils.py: Add hyphen to sanitization char_map (1 line)
• tests/memory/test_neo4j_cypher_syntax.py: Add 5 test cases for the sanitization function

Testing

All 5 new tests pass:

tests/memory/test_neo4j_cypher_syntax.py::TestSanitizeRelationshipForCypher::test_hyphen_replaced_with_underscore PASSED
tests/memory/test_neo4j_cypher_syntax.py::TestSanitizeRelationshipForCypher::test_multiple_hyphens PASSED
tests/memory/test_neo4j_cypher_syntax.py::TestSanitizeRelationshipForCypher::test_no_special_chars_unchanged PASSED
tests/memory/test_neo4j_cypher_syntax.py::TestSanitizeRelationshipForCypher::test_spaces_not_handled_here PASSED
tests/memory/test_neo4j_cypher_syntax.py::TestSanitizeRelationshipForCypher::test_existing_chars_still_sanitized PASSED