Please add dbcode-disconnect / dbcode-connect MCP tools for file-based database lock management

[IainColledge]

What

Add dbcode-disconnect and dbcode-connect MCP tools that allow agents to programmatically disconnect and reconnect named database connections.

Why (problem/use case)

DuckDB uses exclusive file locking — only one process can hold a write connection at a time. When an AI agent uses dbcode-execute-query to inspect data (e.g., validating a dbt model output), DBCode holds the connection open. Any subsequent build tool (dbt, DuckDB CLI) that needs write access fails with:

IO Error: Cannot open file "...duckdb": The process cannot access the file because it is being used by another process.

Today the only workaround is asking the user to manually click disconnect in the DBCode panel — breaking the agent's autonomous workflow. With dbcode-disconnect / dbcode-connect, an agent could:

1. Connect → query to validate results → disconnect
2. Run dbt build / DuckDB CLI commands
3. Reconnect → query to verify

This is a common pattern in data engineering workflows where agents alternate between querying results and running build pipelines against the same database file.

Additional Context

• This only affects file-based databases with exclusive locking (DuckDB, SQLite). Server-based databases like Fabric/Postgres are unaffected — multiple concurrent connections work fine.
• The existing dbcode-get-connections tool already returns connection IDs, so dbcode-disconnect / dbcode-connect could accept those same IDs.
• Suggested signatures:
  • dbcode-disconnect(connectionId) — close the connection, release file lock
  • dbcode-connect(connectionId) — reopen a previously configured connection
• Ideally dbcode-execute-query could also accept an autoDisconnect: true parameter that closes the connection after returning results, for fire-and-forget validation queries.

[IainColledge]

Thank you Mike.

[mikeburgh]

Released in 1.29.4

[IainColledge]

This is what happened when I tried with 1.29.4, let me know what I can do to help debug this.

Connection used: DuckDB connection named database_name
What worked: DBCode connection discovery and query execution worked as expected
What failed: Disconnect through the DBCode tool API failed
Error returned: Tool dbcode-disconnect does not have an implementation registered.

[mikeburgh]

Fixed in 1.29.5