GraphCare — Structural Database Health Scanner

Structural database health scanner. Audits schema topology for orphaned tables, missing indexes, nullable FKs, circular dependencies — without ever reading row data. Supports PostgreSQL, MySQL, SQLite.

The first structural antivirus for AI databases. Scans your schema topology for hidden problems — without ever touching your data.

Why

AI agents evolve schemas at speed. But nobody audits the structure. Over time:

• Foreign keys lose their indexes (JOINs slow to a crawl)
• Tables drift into isolation (orphaned, unreachable data)
• Primary keys go missing (replication breaks, ORMs fail)
• Nullable FKs create silent referential gaps
• Circular dependencies make inserts impossible
• Redundant indexes waste disk and slow writes

GraphCare catches all of this in one scan.

Zero-Trust by Design

GraphCare only queries metadata (information_schema, PRAGMA, pg_indexes). It is structurally impossible for it to read, leak, or mutate your row data.

• READ-ONLY: Zero writes, zero mutations
• NO ROW DATA: Only schema metadata is accessed
• STATELESS: Memory purged after every scan

Setup

GraphCare is an MCP server. Add it to your MCP client config:

{
  "mcpServers": {
    "graphcare": {
      "command": "node",
      "args": ["/path/to/graphcare/index.js"]
    }
  }
}

Or run via Docker:

docker build -t graphcare .
docker run -i graphcare

Or install from npm:

npm install -g graphcare-mcp
graphcare-mcp

Tools

audit_db_structure

Full structural scan. Pass a connection string, get a complete health report.

Parameters:

• connection_string (required) — Database URI: postgresql://, mysql://, sqlite:///path/to/db, or just file.db

Returns: JSON report with:

• db_type — Database engine detected
• tables[] — All tables found
• findings[] — Each structural issue with type, severity, table, and message
• metrics{} — Counts per finding type + computed health_score (0-100)

Example:

Use graphcare to audit my database at postgresql://localhost:5432/myapp

The agent calls audit_db_structure with the connection string and receives a structured JSON report.

explain_finding

Plain-language explanation of any finding type. Includes severity, impact, and recommended fix.

Parameters:

• finding_type (required) — One of: orphaned_table, missing_fk_index, duplicate_index, nullable_fk, no_primary_key, circular_dependency
• context (optional) — Table or column name for specific advice

What GraphCare Detects

Finding	Severity	Impact
Orphaned Tables	Warning	Structurally isolated dead weight
Missing FK Indexes	Critical	#1 cause of slow JOINs and DELETEs
No Primary Key	Critical	Breaks replication and ORMs
Nullable Foreign Keys	Warning	Hidden referential integrity gaps
Circular Dependencies	Warning	Makes clean inserts impossible
Duplicate Indexes	Info	Wasted disk, slower writes

Supported Databases

• PostgreSQL — Full 6-finding detection via information_schema + pg_indexes
• MySQL — Full detection via information_schema
• SQLite — Full detection via sqlite_master + PRAGMA

Security

This tool runs read-only queries against database metadata catalogs only. It never executes SELECT on user tables, never writes, and holds no state between invocations. Connection strings are received via MCP JSON-RPC over stdin — never exposed in process listings.

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