Call a stored function or RPC endpoint in Supabase by passing the function name and arguments.
Call a stored function or RPC endpoint in Supabase.
| Name | Required | Description | Default |
|---|---|---|---|
| args | No | Arguments to pass to the function | |
| function | Yes | Name of the stored function to call |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided, so the description carries full burden. It does not state whether calls are read-only or mutating, whether the function executes with elevated privileges, what errors look like, or any side-effect characteristics. For an RPC invocation tool this leaves substantial unknowns.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single efficient sentence with no waste and front-loaded verb. Slightly under-specified rather than verbose.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a mutation-capable RPC tool with no annotations, no output schema, and a free-form args object, the description should disclose side effects, privilege/auth requirements, and how it relates to sibling tools like supabase_execute_sql. None of that is present.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%: both 'function' (name) and 'args' (arguments object) are documented in the schema. The description adds no format or semantic detail beyond the schema, so baseline 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb (Call) and resource (stored function / RPC endpoint in Supabase). The dual phrasing 'stored function or RPC endpoint' is slightly ambiguous but the intent is clear. It does not differentiate from siblings like supabase_execute_sql, which is a meaningful gap given 12 siblings.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No when-to-use, when-not-to-use, or alternative guidance. An agent seeing both supabase_rpc and supabase_execute_sql has no description-level signal about which to pick.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.