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

Annotations already cover safety (readOnly, idempotent, non-destructive), and the description adds genuinely new behavioral context: the OR logic of the test, that primary residence equity is INCLUDED, that pension is included by default (overridable via include_pension_in_test), joint vs single handling, and the return contents including a routing recommendation and private bank list.

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?

Front-loaded with the verb, the tool's purpose and the thresholds, then supporting detail. Some content (firm attribution and FRN) is marketing-flavored, but it also establishes regulatory authority and is short enough not to obscure the operational content.

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 no output schema, the description explicitly enumerates what is returned (verdict, per-applicant breakdown, joint aggregate, routing recommendation, bank list), and the required vs optional applicant shape is clear from the schema plus the applicant_2 note. An agent has enough to call it correctly.

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 baseline 3 applies. The description goes beyond the schema by explaining the default treatment of pension in the net assets test and the per-individual vs joint household semantics, though it does not walk through the asset/debt netting inputs.

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 whether a UK mortgage applicant qualifies as a high net worth mortgage customer under FCA MCOB 3A') and gives the exact pass thresholds (GBP 300k income OR GBP 3m net assets). This is clearly distinguishable from the sibling calculators/analysers, which are numeric tools rather than regulatory qualification tests.

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?

The closing 'Use when a user asks whether they qualify... about MCOB 3A... private bank mortgages' clause gives concrete triggering contexts. It does not, however, state when-not to use it or name an alternative tool, so it stops short of a 5.

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