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

Annotations already establish that this is read-only, idempotent, and non-destructive. The description adds meaningful context beyond those annotations: what each result contains, the meaning of pre-approval, and that results include an external link with a free test fit. It does not mention pagination or error behavior, but those are minor for a search tool.

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 front-loaded with the tool's purpose, then gives usage context, an alternative, and a concrete example. Every sentence adds value, and the example is especially helpful for an agent constructing valid query parameters. Despite its length, it remains well-structured and focused.

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 correctly explains what each result carries and routes detail retrieval to `fetch`. It avoids needing to document return values as a separate schema. However, it does not explicitly state the response container shape or pagination behavior, which an agent might need to handle cursor-based result sets.

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 57%, so the description needs to compensate. It adds a useful example for `bedrooms_min`, `max_sqft`, and `pre_approved_in`, and explains how to filter by city. However, `min_sqft`, `max_sqft`, and `bedrooms_min` are not described in prose, and the description only partially compensates for the uncovered parameters.

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 states a specific verb ('Search'), a specific resource ('A-du Build, the marketplace of ADU plan sets'), and enumerates the result fields. This clearly distinguishes it from sibling tools like `fetch`, which is explicitly routed to for single-plan details.

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 gives explicit natural-language use cases such as 'find me an ADU plan' and 'what pre-approved plans exist for <city>'. It also directly tells the agent when to call the sibling tool `fetch` instead, providing a clear alternative with the required identifier format.

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