Full replace (PUT) a single record matching a filter. All columns must be specified including the primary key. Creates the record if it does not exist.
Part of the Postgrest server.
Free to start. No card required.
AI agents use pg_replace_record 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_replace_record repeatedly, creating or modifying resources faster than any human could review. PolicyLayer'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.
{
"version": "1",
"default": "deny",
"tools": {
"pg_replace_record": {
"limits": [
{
"counter": "pg_replace_record_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Postgrest policy for all 10 tools.
These attack patterns abuse exactly the kind of access pg_replace_record gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Full replace (PUT) a single record matching a filter. All columns must be specified including the primary key. Creates the record if it does not exist.. 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.
Register the Postgrest MCP server in PolicyLayer and add a rule for pg_replace_record: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Postgrest. Nothing to install.
pg_replace_record 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_replace_record rule in your PolicyLayer 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 PolicyLayer policy for pg_replace_record. 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_replace_record is provided by the Postgrest MCP server (@supabase/mcp-server-postgrest). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 10 Postgrest tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.