Return one table's columns, types, row count and byte count, without running a query -- how an agent discovers its own table shape.
| Name | Required | Description | Default |
|---|---|---|---|
| table | Yes | Name of the declared table to describe. | |
| tenant_key | No | The key `signup` returned. Required only when this connection carries no Authorization: Bearer header -- when both are present, the header wins. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the full disclosure burden. It usefully signals a cheap metadata read with no query execution and enumerates the returned metrics, but it says nothing about permission requirements, behavior for a missing/unauthorized table, or whether row/byte counts are exact or estimated.
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 dense sentence with the resource and the differentiator front-loaded and zero filler. Every clause (what is returned, no query execution, use case) earns its place.
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?
With no output schema, the description correctly enumerates the return shape (columns, types, row count, byte count), and auth semantics live in the schema. It is nearly complete for a simple introspection tool, missing only error/failure behavior.
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 coverage is 100% and the tenant_key description already explains the Authorization-header precedence rule in detail, so the schema does the heavy lifting. The description only adds the implicit 'one table' scope for the table parameter, which is baseline-level value.
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 (return) and resource (one table's columns, types, row count, byte count), and the clause 'without running a query' explicitly differentiates it from query-based siblings such as host.table.query. An agent knows exactly what it gets without opening the schema.
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?
The phrase 'how an agent discovers its own table shape' gives clear context for when to reach for it (introspection instead of querying), which is useful routing against host.table.query. It stops short of naming alternatives or stating when-not-to-use (e.g. host.table.list for enumerating all tables), so it is clear but not exhaustive.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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