List prewarmed relations

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

The description goes beyond the readOnlyHint annotation by detailing the extension dependency, the empty list scenario when the extension is missing, and the specific output fields. This adds valuable behavioral context that the annotation alone does not provide. No contradictions with annotations.

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 concise (three sentences plus an example), front-loaded with the purpose, and contains no extraneous information. Every sentence adds value.

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 description covers the core functionality, extension requirement, and return fields (output schema exists, so returns need not be fully listed). It is fairly complete for a list tool, though it could mention the database parameter's role in multi-database setups more explicitly.

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?

Only the database parameter has a description in the schema. The main description only shows an example usage for schema and limit without explaining their semantics. With 33% schema description coverage, the description should compensate more but only partially does so via the example.

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 clearly states the tool reports 'current shared-buffer residency per relation, ranked by blocks-cached descending.' It specifically mentions the required extension and empty list behavior. However, it does not explicitly differentiate from similar sibling tools like read_pg_buffercache_relations, though the name 'prewarmed' and the extension requirement imply a distinct focus.

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 description provides an example call (filtering by schema and limit) and notes the extension requirement, which gives some usage context. However, it lacks explicit guidance on when to use this tool versus alternatives (e.g., read_pg_buffercache_relations) and does not outline prerequisites or side effects beyond the extension.

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