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

No annotations are present, so the description carries the full burden. 'Report' implies a read-only operation, and it enumerates the data categories, but it does not disclose whether results are cached, how ingestion timing is determined, or any operational characteristics such as data source or latency. This is a minimal behavioral disclosure.

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 a single sentence that starts with the verb and packs the key output categories without filler. It is appropriately concise for a zero-parameter tool.

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 zero-parameter reporting tool, the description covers the essential return areas, but it leaves 'local' under-specified: it never explains how the local market is determined. Since there is no output schema, a bit more detail about the returned values would improve completeness.

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 zero parameters and 100% schema coverage by definition, so there is no parameter semantics for the description to add. The baseline of 4 applies.

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 uses the verb 'Report' and names concrete resources: local data coverage across apps, reviews, chart snapshots, and the last ingest run. This clearly differentiates it from siblings like explain_method or validate_paying_market, which address different concerns.

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?

No explicit guidance is given on when to use market_stats versus alternative tools. The description only states what it reports, so an agent must infer from the sibling names that this is the coverage/ingest-status tool.

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