pg_inspect_locks

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

Annotations indicate read-only, idempotent, non-destructive behavior. The description adds important behavioral context: it shows current lock contention, returns multiple rows per blocked session, and includes a caveat that 'relation' is a best-effort hint for non-relation waits. No contradiction 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 appropriately sized and front-loaded: it starts with the core purpose, then details row shape and caveats. Every sentence adds value, and there is no redundancy or filler.

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?

Despite no output schema, the description thoroughly explains return values (blocked PID, blocking PID, etc.), row shape, and a critical caveat about 'relation'. For a simple tool with one parameter, this is complete and actionable.

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?

The single parameter 'limit' is fully documented in the schema (default 50, max 100, min 1). The description does not add significant meaning beyond the schema, but given 100% schema coverage, a score of 3 is appropriate.

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 shows lock contention, specifically which sessions are blocked and blocking, with fields like blocked PID, blocking PID, lock types, relation, and queries. This distinguishes it from sibling tools like pg_health or pg_query, which do not focus on locks.

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 advises using this tool first when a tool call hangs or the app feels stuck, as it is the fastest way to identify long-held transactions holding locks. It also explains row shape and caveats, helping the agent decide when to use it.

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