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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, destructiveHint=false, so the safety profile is covered. The description adds the non-obvious behavioral constraint that at least one filter must be supplied, which is not derivable from the annotations and prevents a wasted call. It does not discuss rate limits or pagination semantics beyond what the schema states.

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 tight sentences: the first leads with purpose and scope, the second with the invocation constraint and return shape. No filler, no restatement of the title, and the most decision-relevant facts are front-loaded.

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 usefully enumerates the returned fields (certificate number, address, postcode, council, constituency, efficiency band, registration date), which is exactly the gap structured data leaves open. Combined with the mandatory-filter rule and full schema coverage, an agent has everything needed to call this 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 every parameter is already documented in the schema, establishing the baseline of 3. The description adds only the meta-statement that the filter set matches search_domestic_epc and that one is required; it contributes no per-parameter syntax or format detail beyond the schema.

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 (Search) plus the precise resource (UK Energy Performance Certificate register) and narrows scope to NON-DOMESTIC (commercial) buildings in England and Wales. This directly differentiates it from the sibling search_domestic_epc without needing to open either schema.

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?

Explicitly states the key usage constraint: 'Same filters as search_domestic_epc — at least one is required.' That tells the agent the tools share a filter surface and that an empty call will fail. It doesn't spell out when to prefer this over search_domestic_epc or get_certificate beyond the implicit domestic/non-domestic split, so it stops short of full alternative routing.

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