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

Beyond the readOnlyHint annotation, the description discloses important behavioral context: the index may or may not exist, searches become live S3 walks without it, and it explains staleness and several field meanings including datetime_suspect, quarantined_future_count, and unique_captures. This is substantive context that helps an agent interpret the tool's output and trade-offs.

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 front-loaded with the core purpose and then adds useful field semantics. It is somewhat long because it explains return fields that may already be documented in the output schema, but every sentence remains informative and there is no 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?

Given zero parameters, a readOnly annotation, and an output schema, the description provides everything an agent needs: what the tool reports, why to use it, and how to interpret key fields. No critical context appears to be missing.

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 tool has zero parameters, so the baseline is 4. The description correctly does not invent parameter details, and the input schema is empty and fully covered.

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 a specific verb and resource: 'Report on the local catalog index'. It also explains what the report is for, but does not explicitly contrast the tool with the sibling search_catalog or other stats tools, so it falls short of full sibling differentiation.

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?

It gives a clear usage context: 'Lets a long-running agent decide whether searches will be instant (index present) or pay a live S3 walk, and how stale the snapshot is.' This tells the agent when the tool is valuable, but does not name an alternative tool or state when not to use it.

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