Read PG buffercache relations

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

Beyond the readOnlyHint annotation, the description discloses that the extension must be installed and that it returns available=false if not, adding significant behavioral context not present in 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?

Three sentences, each adding crucial information: purpose, filtering, and requirements. No wasted words, front-loaded with primary action.

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?

Given an output schema exists, the description covers purpose, filtering capability, required extension, and behavior when extension is missing. No gaps for this tool's complexity.

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?

With only 33% schema description coverage, the description adds meaning for the 'schema' parameter by stating it allows filtering. However, it does not describe 'limit' or add to 'database' beyond the schema description. Partial compensation.

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 it reads the list of relations in the PostgreSQL shared buffer cache with specific fields (buffered size, percentage, etc.), distinguishing it from the sibling 'read_pg_buffercache_summary' which likely provides aggregate statistics.

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 mentions filtering by schema and the requirement for the pg_buffercache extension, but does not explicitly compare to sibling tools or state when not to use. It provides clear context on prerequisites and fallback behavior.

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