location_coverage

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

There are no annotations, so the description carries full burden. It discloses that the tool returns coverage metadata (table-by-table, spans, gaps) rather than location data, and warns about the interpretive pitfall. This provides meaningful behavioral context beyond simply stating 'shows coverage.'

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 two sentences long and front-loaded: the first sentence states the tool's output directly, and the second provides a concise usage warning. Every word earns its place; 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?

For a zero-parameter tool with no output schema, the description covers purpose, output scope, and usage context. It could optionally include an example of the response structure, but the current content is sufficient for an agent to decide when to use it and what to expect.

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, and the schema confirms this with 100% coverage. The description adds context about the output (tables, spans, gaps) but no parameter details are needed. Per the rubric, 0 params yields a baseline of 4, and the description aligns well with that.

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 what the tool does: it reports what the archive holds, table by table, including the span each source covers and gaps of two weeks or more. It uses a specific resource ('the archive') and distinguishes itself from sibling location-query tools by focusing on data coverage rather than location data itself.

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?

The second sentence explicitly instructs when to use this tool: 'Check this before concluding someone was never somewhere.' It also explains the critical distinction between 'no record' and 'was not there,' which is valuable guidance. While it doesn't name specific alternative tools, the context makes the usage clear.

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