Database MCP

MCP write proposals

A write tool creates an evidence-backed proposal; it does not directly change Postgres or MySQL.

Overview

A Synapsor proposal tool reads the current authorized row, derives before from the database, derives patch from reviewed fixed values or validated arguments, calculates after, attaches evidence, and stores the exact proposal.

For external Postgres/MySQL, source_database_changed remains false during proposal creation. The source changes only after approval and trusted runner writeback.

Review required is a successful tool result. It means the model asked for a risky state change and Synapsor kept it reviewable.

Developer notes

Do not present proposal creation as a database write.
Show exact before/proposed values to the reviewer.
Attach evidence and query audit to the proposal.
Use Approve for writeback for external DBs, not merge.

Proposal result

proposal.json

{
  "status": "review_required",
  "proposal_id": "wrp_123",
  "target": {
    "type": "invoice",
    "id": "INV-3001"
  },
  "diff": {
    "late_fee_cents": {
      "before": 5500,
      "proposed": 0
    }
  },
  "source_database_changed": false
}