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

Annotations only declare readOnly and openWorld, so the description usefully adds real behavioral contract: granularity boundaries (monthly from Oct 2024, quarterly FY2017–FY2024 Q2, never mixed or interpolated), oldest-first ordering, and that unreadable or blank periods surface as gaps with a reason. It does not say what happens with an unmatched status value, which is the main remaining gap.

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 sentences, front-loaded with the question the tool answers, then the output contract with the key constraints. Dense but each clause (granularity, ordering, gaps) conveys a distinct behavioral fact; only the 'Give status and optionally...' clause is 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?

With an output schema present, return formatting need not be explained, and the description still covers granularity, ordering, gap reporting, and optional dimensions. Nothing an agent needs in order to call this correctly and interpret the series is 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?

Schema description coverage is 100% and includes enum values and examples, so the schema already carries this load. The description merely restates required/optional status and omits any enumeration or format guidance beyond the schema; baseline 3 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 states a specific resource and scope: historical average processing time series for a given status of residence, broken out by procedure and measure. An agent can distinguish this from residence_processing_latest by the explicit 'changed over time' / 'Returns series' framing, though the sibling is never named.

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?

'Give status and optionally procedure and measure' implies how to call it, and the time-series framing implies when to use it, but there is no explicit when-to-use statement or routing to alternatives. It never says to use residence_processing_latest for current figures or residence_processing_statuses to resolve keys — the latter hint lives only in the schema.

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