pg_health

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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false. The description adds context about the type of data returned (server version, db size, etc.) but does not disclose any behavioral traits beyond those already in annotations. For example, it doesn't mention if the snapshot is a single database scope or all databases. The description adds marginal value.

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 two concise sentences. The first sentence states what the tool does, listing key elements. The second sentence gives usage context. Every word earns its place; no redundancy or fluff. It is front-loaded with the most important information.

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 the tool's simplicity (one optional parameter, read-only, no output schema) and the rich annotations, the description adequately covers use cases. It does not need to explain return values since none are specified. However, the tool is part of a large sibling set with many specific diagnostic tools; a brief mention of when to choose pg_health over others would improve completeness, but it is still satisfactory.

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 input schema has one parameter (activeQueryLimit) with 100% coverage in its description, which provides full semantics (range, default). The tool description mentions 'active queries' but does not add any additional meaning about the parameter beyond what is already in the schema. Since the schema is self-explanatory, baseline 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 returns a 'quick health snapshot' listing specific metrics (server version, database size, connection count, active queries, table count). It distinguishes itself from siblings by aggregating multiple health indicators rather than focusing on a single query or table. The verb 'snapshot' implies a non-modifying read operation.

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 explicitly says it is 'useful as a connection sanity check and to spot runaway queries,' providing clear use cases. However, it does not explicitly state when not to use it or mention alternative tools by name. The sibling list includes more specialized tools like pg_top_queries and pg_inspect_locks, but the description does not guide the agent to them for deeper investigation.

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