pg_unused_indexes

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

Provides key behavioral detail: relies on statistics reset. No annotations exist, so description carries full burden. Lacks mention of permissions, freshness of stats, or any non-obvious side effects.

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?

Two sentences, front-loaded with purpose and condition, then use case. No fluff.

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?

No output schema and description omits return value format (e.g., columns returned like index name, table, size). Without this, agent lacks full understanding of tool's output.

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% for both parameters (schema, connectionId). Description adds no additional parameter meaning beyond schema, meeting baseline.

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?

Clearly states 'Find indexes that have never been used' with specific condition (zero scans since last stats reset) and target action (identify candidates to DROP). Distinguishes from siblings like pg_list_indexes and pg_index_usage.

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?

Explicitly states the use case: identifying indexes to drop to save space and reduce write overhead. Does not provide when-not-to-use or alternative tools, but context is clear enough.

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