Account holder

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds value beyond that by fixing the enumerable output domain and framing the tool as a router, though it does not say what happens when no holder exists or whether the call is cheap/cacheable.

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?

Two short sentences, zero filler, and the routing insight is placed after the return contract where it is most useful. Nothing could be removed without losing information.

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 carries the burden of explaining the return value and does so precisely (UID plus one of four type values), then tells the agent what to do with that result. Complete for a zero-parameter lookup of this scope.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; per the rubric a 0-parameter tool has a baseline of 4. The description correctly stays silent on inputs rather than inventing any.

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 ('Returns the account holder UID and type') and enumerates the exact return domain (INDIVIDUAL, JOINT, SOLE_TRADER, BUSINESS). This clearly separates it from close siblings like get_account_holder_name, which returns a name rather than an identity/type pair.

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 second sentence gives real routing guidance: the returned type determines which downstream details tool applies, implicitly pointing at get_individual_details / get_joint_account_details / get_business_details / get_sole_trader_details. It stops short of naming the specific tool per type value, so it is clear context rather than a fully explicit when-to-use rule.

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