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

Annotations already declare readOnlyHint, idempotentHint, and closed-world behavior, so the safety profile is covered. The description contributes beyond that by disclosing that results include document counts, which is the only return-shape information available since no output schema exists.

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 short sentences with the resource first and the routing guidance second; no filler and nothing duplicated from the schema or annotations.

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?

For a no-parameter, read-only list tool with no output schema, the description covers what comes back (collections with counts) and why you'd call it. Minor gaps such as ordering or pagination are not addressed but are unlikely to matter at this scale.

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 means there is little to document, so the baseline is high. The description still adds value by tying the tool's output to a parameter on another tool (the collection filter on search_records), clarifying how the data is consumed.

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?

Specific verb-resource pair ('The collections in this server') plus a statement of what the response contains ('with document counts'). It is clearly distinguishable from siblings like archive_stats or search_records because it returns the collection vocabulary rather than statistics or records.

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?

Gives two concrete use cases: browsing what the archive holds, and obtaining valid values for the collection filter on search_records. This is real routing guidance, though it never says when to prefer archive_stats over this for a high-level overview.

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