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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds genuinely non-obvious context: jurisdiction limits, the 1 May 2026 commencement boundary, and the negative scope on rent fairness. It doesn't discuss how 'unknown' history or 'unsure' prescribed form are handled, which is the remaining behavioral 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?

A single front-loaded sentence naming the resource and scope first, then the outputs, with zero filler. The colon-and-comma construction makes it dense to parse in one pass, which keeps it just short of ideal structure.

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, the description needn't explain returns, and annotations carry the safety profile; what remains is scope and limits, which are covered. The only omission is guidance on how uncertain inputs (history 'unknown', prescribedForm 'unsure') affect the result, which an agent might want before calling.

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 all seven parameters, including the three enum-constrained ones, are documented in the schema itself. The description adds no parameter-level meaning beyond what the schema already says, so the 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?

States a specific verb and resource ("Check a section 13 rent increase notice") and pins the scope precisely: assured periodic tenancy, England, served from 1 May 2026. It also enumerates the three things it evaluates, so an agent knows exactly what answer shape to expect and can distinguish it from the employment/other-tenancy siblings.

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?

Gives clear applicability conditions (England only, assured periodic tenancy, notices served on or after 1 May 2026) and one explicit exclusion ("does not judge whether the new rent is fair"). It does not name a sibling or alternative tool for the excluded question, so routing for fairness checks is left to inference.

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