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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, but the description adds behavior the schema and annotations cannot: results are summaries rather than full documents, matched sub-questions return inline with their answers, and coverage is limited to the United Kingdom. These are real operational facts an agent needs before calling.

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 purpose and the primary usage directive, and each paragraph carries a distinct fact (scope, follow-up tool, inline Q&A, geography). The closing two sentences about UK coverage slightly restate the opening scope, costing a little tightness.

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?

An output schema exists, so return structure need not be spelled out, and the description still covers the essentials: what the corpus contains, what results look like at a high level, the follow-up path, and the geographic boundary. Nothing needed to call it correctly is missing.

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%, so both the query and limit parameters are already documented in the schema, including 'plain words work best' and the 1-25 range. The description adds no syntax, format, or ranking detail beyond that, so the baseline 3 applies.

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?

Names a specific verb and resource ('Search the guides, articles and questions') and scopes the corpus to UK home energy subjects. It also distinguishes itself from the sibling get_document by stating that searching returns summaries and get_document reads one in full.

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 says to use this first before answering from memory, enumerates the question types it covers (sizing, standards, quotations, planning permission), and routes the agent to get_document as the follow-up. That is close to a complete when-to-use instruction.

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