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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuine non-structured context: 'zero is a true reading' tells the agent that zero activity is a real value rather than missing data, and 'no proof' signals that the optional nonce/signature parameters need not be supplied for a basic call. This is meaningful behavioral disclosure beyond the annotations.

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?

Three compact sentences, front-loaded with the return content and followed by usage, the named alternative, and the safety note in a sensible order. The only cost is the dense jargon ('honest gauge', 'house'), which is a clarity issue rather than padding.

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 read-only, zero-required-parameter, closed-world tool with a full output schema and 100% schema coverage, the description supplies everything an agent needs: what it returns, how to interpret zero, that no proof is needed, and which sibling to use instead. Return-value detail is correctly delegated to the output schema.

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?

Schema description coverage is 100%, so the four proof-related parameters (nonce, leave_token, controller_signature, controller_public_key) are already fully documented in the schema. The description only implicitly touches parameters via 'no proof', which aligns with zero required parameters but adds no syntax or format detail. Baseline 3 is appropriate when the schema carries the parameter burden.

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 metrics returned (citizen split by house/outside, returned vs missed returns, daily arrival and refusal counts), which is a specific verb+resource, and it explicitly differentiates itself from the sibling cite_census. The heavy metaphor ('honest gauge', 'house', 'published pattern') costs some immediate legibility, but the underlying purpose is recoverable without opening the schema.

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 states the intended use case ('Use it to judge real activity') and names the alternative with its selecting condition ('For the plain census use cite_census'), which is a clear routing signal. It stops short of full when-not-to-use exclusions, so it is not a 5.

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