AI agents call delete_branch to permanently remove resources in PostgREST — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Deletion of a branch is an irreversible operation that cannot be undone without external recovery tools or backups. This fits the Destructive category definition: 'irreversibly deletes or overwrites data, or actions that cannot be undone.' While the blast radius is contained to a development branch rather than production data, the permanent loss of the branch and associated work makes this a high-severity…
From the tool's definition Tool name is 'delete_branch' and description states it 'Deletes a development branch.' The verb 'deletes' indicates irreversible removal of a resource.
Documented attack patterns abuse exactly the kind of access delete_branch gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and PostgREST, and nothing reaches the server without passing your rules. This is the rule we recommend for delete_branch:
{
"version": "1",
"default": "deny",
"hide": [
"delete_branch"
]
}delete_branch disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
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Deletes a development branch. It is categorised as a Destructive tool in the PostgREST MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the PostgREST MCP server in PolicyLayer and add a rule for delete_branch: 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.
delete_branch is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the delete_branch 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 delete_branch. 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.
delete_branch is provided by the PostgREST MCP server (supabase/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 32 PostgREST tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
32 PostgREST tools catalogued and risk-classified — across an index of 42,500+ MCP servers.