Postgres Explain

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the behavioral disclosure burden and does state the key trait: it runs EXPLAIN without ANALYZE and without executing side effects. It omits details like connection/auth, but the safety-critical distinction is present.

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?

The description is a single front-loaded sentence with no filler. Every phrase contributes: the command variant, the query type, and the no-execution guarantee.

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?

The core behavior and no-side-effect guarantee are clear, and an output schema covers return values. However, because the schema has zero property descriptions, the optional params field is left completely unexplained, leaving a real completeness gap for a tool with two parameters.

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 0%, so the description must explain both parameters. It only implies that sql holds a SELECT statement and says nothing about params, such as whether params supplies bind values for placeholders like $1 or how they are passed. This is a significant gap.

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 names a specific operation (EXPLAIN with FORMAT TEXT) and the target resource (a SELECT). It also differentiates itself from executing the query by explicitly noting no ANALYZE / executing side effects, so an agent can distinguish it from postgres_query_readonly.

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 'without ANALYZE / executing side effects' phrase gives clear context that this tool is for obtaining query plans rather than running the query. It does not explicitly name postgres_query_readonly as the execution alternative or list exclusions, but the intended use is evident.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.