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

Annotations already establish the safe-read profile (readOnly, idempotent, non-destructive, closed-world), so the description needn't repeat it. It adds value by disclosing the actual content returned — parcel volumes, data freshness, open trades, proven signals — which is important since there is no output schema. It doesn't mention result size, pagination, or formatting.

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?

A single sentence that front-loads the resource and then the contents, ending with the call-first advice. Dense but every clause adds information; only minor trimming would improve it.

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?

With no parameters, no output schema, and annotations already covering safety, the description carries the return-value burden and does so by enumerating the fields an agent can expect. Missing only detail on output shape or size, which is a minor gap for a zero-arg discovery tool.

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?

There are zero input parameters, so there is nothing to disambiguate; baseline 4 applies. The description correctly implies the tool takes no arguments by framing itself as a global coverage inventory.

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 names the concrete resource (coverage of counties/cities in shinnslist) and enumerates what the listing reports: parcel counts, data freshness, open buyer trades, and proven signal counts. It's clearly a read-oriented inventory tool, distinguishable from siblings like find_parcels or list_signals, though it never names a sibling explicitly.

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?

Provides an explicit trigger: 'Call it first when unsure whether an area is covered.' That gives the agent a clear entry-point condition. It stops short of stating when NOT to use it or naming which sibling to use for specific lookups once coverage is confirmed.

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