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

Annotations already declare read-only, idempotent, open-world and non-destructive, so the safety profile is covered. The description adds substantial context beyond that: the data source and freshness (a daily copy of the SRA register), the matching precedence (Companies House number, then registered/former names, then SRA number), the enumerable outcomes (authorised, authorised with conditions, ceased, revoked, intervened), and the coverage window since 8 October 2026.

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 answerable question is front-loaded, followed by source, matching logic, returned fields and scope limits as compact clauses. It is dense and mostly waste-free, though the enumerations of statuses and returned fields make it longer than strictly necessary for a one-parameter lookup.

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?

There is no output schema, so the description carries the full burden of describing returns, and it does: statuses with dates, kind of firm, work areas, offices and head office, trading and former names, and recorded changes. Combined with the source, freshness and entity scope, an agent has everything needed to call and interpret this tool.

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?

With a single parameter at 100% schema coverage, the baseline is 3, but the description goes further by explaining the resolution order the single string is matched against — register Companies House number first, then registered/former names, then SRA number. That materially changes how an agent should populate the field, which the schema description alone does not convey.

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 opens with a concrete question it answers — whether a firm is SRA-authorised, what kind, since when, and whether that changed — naming the verb, resource and the register it draws from. An agent can distinguish it at a glance from siblings like cqc_check, charity_check or sponsor_licence, which cover entirely different registers.

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 clear applicability (law firms regulated by the SRA) and an explicit boundary: 'Firms only, never individuals.' That exclusion is useful routing guidance. It stops short of naming a sibling to use for individuals or other regulated-entity checks, so it is clear context rather than fully prescriptive when/when-not guidance.

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