Insert or update records (upsert). Uses "merge-duplicates" (update existing) or "ignore-duplicates" (skip existing) resolution. Conflict detection uses primary key by default, or specify on_conflict column.
Part of the Postgrest MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.
AI agents use pg_upsert_records to create or modify resources in Postgrest. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call pg_upsert_records repeatedly, creating or modifying resources faster than any human could review. Intercept's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Postgrest.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
tools:
pg_upsert_records:
rules:
- action: allow
rate_limit:
max: 30
window: 60See the full Postgrest policy for all 10 tools.
Agents calling write-class tools like pg_upsert_records have been implicated in these attack patterns. Read the full case and prevention policy for each:
Other tools in the Write risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.
Insert or update records (upsert). Uses "merge-duplicates" (update existing) or "ignore-duplicates" (skip existing) resolution. Conflict detection uses primary key by default, or specify on_conflict column.. It is categorised as a Write tool in the Postgrest MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Add a rule in your Intercept YAML policy under the tools section for pg_upsert_records. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Postgrest MCP server.
pg_upsert_records is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the pg_upsert_records rule in your Intercept policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the Intercept policy for pg_upsert_records. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
pg_upsert_records is provided by the Postgrest MCP server (@supabase/mcp-server-postgrest). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Open source. One binary. Zero dependencies.
npx -y @policylayer/intercept