Retrieve column definitions, data types, and primary key for a specified table in the demo database to inspect its schema.
Describe one table in the demo database, including columns, types, and primary key.
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | Table name. Use schema-qualified form if needed (e.g. "public.users"). |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden. It usefully discloses the shape of the return (columns, types, primary key), but says nothing about failure modes for a nonexistent table, required permissions, or whether it is strictly read-only beyond the implication of 'describe'.
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 sentence with zero padding, front-loading the action and resource before listing the returned fields. Nothing in it is redundant.
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 simple one-parameter read tool with no output schema, the description compensates by naming the returned fields. Only minor gaps remain around error behavior and permissions, which are not critical for invocation.
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% and there is a single parameter, so the schema already documents the name argument and its schema-qualified syntax. The description adds no format or naming detail beyond what the schema provides, making the baseline of 3 correct.
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?
The description states a specific verb (describe), a scoped resource (one table in the demo database), and enumerates what is returned (columns, types, primary key), so the agent knows exactly what the tool produces. It stops short of naming or contrasting with its siblings list_tables and query, which is the only thing keeping it from a 5.
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?
Usage is only implied: 'one table' hints that list_tables covers enumeration and query covers data retrieval, but neither alternative nor any when-to-use condition is stated. The agent must infer the routing from the sibling names alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.