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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is fully covered. The description adds genuinely useful behavior (results sorted by date, default 90-day lookback, no upper bound), but says nothing about result volume, pagination, or how far ahead 'upcoming' extends.

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?

One front-loaded sentence states what the tool returns and how it is ordered, followed by a tight per-argument block. No filler, no restatement of the tool name, and the most decision-relevant information comes first.

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 three-parameter, read-only list tool with no output schema, the description covers purpose, filtering, sort order, and defaults adequately. The main gap is that it does not hint at the returned shape (e.g. whether rule identifiers are included for follow-up get_rule calls), which matters given there is no output schema to fall back on.

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 0%, so the description carries the burden and largely discharges it: it documents all three parameters, gives the sector enum values, the YYYY-MM-DD format, and the defaults for since and until. Only minor ambiguity remains (whether since/until are inclusive, and what happens if until precedes since).

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 gives a concrete verb-and-resource ('Dated changes in the register: rules that recently came into force and upcoming changes, sorted by date'), so an agent knows this lists time-bound regulatory changes rather than searching rule text. It does not explicitly distinguish itself from the sibling find_rules/get_rule, which is the only thing keeping it from a 5.

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?

Usage is only implied: an agent can infer you call this to see recent and upcoming regulatory dates, and the defaults (90 days back, no upper limit) tell it the default window. There is no statement of when to prefer this over find_rules or get_rule, and no prerequisites or exclusions.

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