MCP Server: Auto-expand subgroup queries when no group_ids specified

[LongSunnyDay]

Problem

When using hierarchical group_ids like evadenta:business, evadenta:procedures, etc., the MCP server's search functions (search_nodes, search_memory_facts, get_episodes) return no results when called without explicit group_ids.

Current Behavior

# Config: --group-id evadenta
# Data stored in: evadenta:business, evadenta:procedures, evadenta:architecture

search_nodes(query="deployment")  # Returns: No relevant nodes found

The enforce_group_scope() function returns ["evadenta"] when no group_ids are provided, but the search performs an exact match, missing all evadenta:* subgroups.

Expected Behavior

search_nodes(query="deployment")  # Returns: nodes from evadenta:business, evadenta:procedures, etc.

Proposed Solution

Add a helper function that queries the database for all group_ids matching the configured prefix:

async def get_matching_group_ids(prefix: str) -> list[str]:
    """Query database for all group_ids that equal prefix OR start with prefix:"""
    # Query: WHERE n.group_id = $prefix OR n.group_id STARTS WITH $prefix_colon
    # Returns: ["evadenta:business", "evadenta:procedures", "evadenta:architecture", ...]

Then modify search_nodes, search_memory_facts, and get_episodes to use this when no group_ids are explicitly provided.

Use Case

Multi-category knowledge storage where data is organized into subgroups:

• project:architecture - design decisions
• project:procedures - deployment/dev workflows
• project:debugging - troubleshooting lessons
• project:business - domain rules

Users expect default queries to search across all their subgroups, not require explicit enumeration.

Implementation

I have a working implementation (~50 lines) that:

1. Adds get_matching_group_ids() async function
2. Modifies the three search functions to auto-expand subgroups
3. Maintains backward compatibility (only affects queries with no explicit group_ids)
4. Preserves existing scope enforcement for security

Happy to submit a PR if this approach aligns with the project's direction.

Environment

• graphiti-core version: latest
• MCP server transport: stdio
• Database: Neo4j