create_branch
Creates a development branch on a Supabase project. This will apply all migrations from the main project to a fresh branch database. Note that production data will not carry over. The branch will get its own project_id via the resulting project_ref. Use this ID to execute queries and migrations o...
This record as markdown: /tools/supabase/create-branch.md
What create_branch does on Supabase
AI agents use create_branch to create or update resources in Supabase, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Supabase environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
name | string | — | Name of the branch to create |
project_id | string | — | |
confirm_cost_id | string | — | The cost confirmation ID. Call `confirm_cost` first. |
Parameters from the server's own tool schema.
Why create_branch is rated Medium
This tool creates a new development branch within a Supabase project, which is a reversible write operation. The branch can be deleted (as evidenced by the sibling tool delete_branch), making it non-destructive. It doesn't execute arbitrary code or delete data irreversibly.
From the tool's definition Tool description states it "Creates a development branch on a Supabase project" and "will apply all migrations from the main project to a fresh branch database." This is explicitly a creation operation that modifies the project structure.
Attacks that exploit this kind of access
The rule that runs create_branch safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Supabase, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For create_branch, this is the rule to start with:
create_branch stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Supabase, apply this rule, and every create_branch call is checked against it from then on.
Questions about create_branch
Creates a development branch on a Supabase project. This will apply all migrations from the main project to a fresh branch database. Note that production data will not carry over. The branch will get its own project_id via the resulting project_ref. Use this ID to execute queries and migrations on the branch. It is categorised as a Write tool in the Supabase MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
create_branch accepts 3 parameters: name, project_id, confirm_cost_id. The full parameter table on this page comes from the server's own tool schema.
Register the Supabase MCP server in PolicyLayer and add a rule for create_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 Supabase. Nothing to install.
create_branch 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 create_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 create_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.
create_branch is provided by the Supabase MCP server (@modelcontextprotocol/server-supabase). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
More on Supabase, and thousands of servers like it.
This server
Across the catalogue