search_epc_by_postcode

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

With no annotations, the description carries full burden. It states that it searches and returns energy ratings and property details, but fails to disclose any behavioral traits such as authentication requirements, rate limits, or how invalid postcodes are handled. This is minimal transparency.

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 very concise: two sentences plus an args line, with no fluff. It is front-loaded with the purpose. However, it could be slightly more structured (e.g., bullet points) for readability, but it's efficient.

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?

The tool has one simple parameter and an existing output schema, so the description need not detail return values. It mentions 'energy ratings (A-G) and property details', which is adequate. However, it does not clarify if multiple certificates are returned or pagination exists, leaving some ambiguity. A 3 is appropriate.

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 description says 'postcode: UK postcode' but adds little beyond the schema's type string. It does not specify format (e.g., spacing), expected length, or any validation rules. With 0% schema coverage, the description should compensate but barely does.

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 'Search for Energy Performance Certificates by postcode', specifying the verb and resource. It distinguishes itself from sibling tools (e.g., search_companies, search_charities) by focusing on EPCs, and the name itself is explicit.

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 no guidance on when to use this tool versus alternatives (e.g., lookup_postcode for general postcode info). No exclusions or prerequisites are mentioned, leaving the agent without context for selection.

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