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

With no annotations, the description carries the full burden, and it discloses key traits: that it is free, processes no data (read-only, no side effects), and that it reveals ordering and limits for diff_rows. It does not describe output format beyond high-level content, but for a metadata/introspection tool the disclosure is strong.

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 tight sentences, front-loaded with what it returns, followed by the when-to-call guidance and a closing note on cost. Zero 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?

Covers what is returned, when to call it, and that it is cheap/read-only – sufficient for an agent to decide whether to invoke it. The only minor gap is the absence of output schema, but the description enumerates the content well enough.

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?

Zero parameters, so baseline is 4. Nothing to document and no schema gaps to compensate for.

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?

States a specific verb (Returns) and enumerates exactly what resource is returned: matching/comparison rules, output row shape and order, max rows per call. It also names the sibling diff_rows whose behavior it describes, distinguishing itself clearly.

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 says 'Call this first if you are unsure how values are compared' – a precise when-to-use condition tied to the single sibling tool. No ambiguity about its role relative to diff_rows.

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