Fetch Full Record from UK Due Diligence Register

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive. The description adds beyond this by disclosing the routing behavior across different registers and the exact ID format required. This helps the agent understand that one tool serves multiple backends, which is not inferable from annotations alone.

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 description is two sentences plus a concise bullet list of four route mappings. Every element earns its place: the first sentence states the action, and the list provides essential routing rules in a scannable format. No fluff or redundancy.

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?

Given that there is a single parameter, a rich output schema, and detailed annotations, the description covers the critical operational nuance—the prefix-based routing—that could otherwise be ambiguous. It is complete for an agent to correctly select and invoke the tool for any of the listed ID types.

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 coverage is 100%: the input schema already fully documents the 'id' parameter with the same format examples. The description's routing list essentially repeats the schema's parameter description, adding no new semantic detail. Thus the baseline of 3 is appropriate since the schema carries the heavy lifting.

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 clearly states 'Fetch the full record for an ID returned by search' and then details the routing by prefix, which both specifies the action and distinguishes it from the sibling-specific fetchers like dd_company_profile and dd_charity_profile. The explicit list of prefix mappings makes the tool's scope unambiguous.

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 description provides clear context for when to use this tool: after a search, with IDs in a specific prefixed format. It does not explicitly state alternatives or exclusions, but the routing list implies which IDs are valid and that this is a unified entry point. It could be stronger by mentioning when to prefer dedicated sibling tools, but it is not misleading.

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