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

Annotations already declare readOnly/idempotent/non-destructive, and the description goes further: library size (~500 plans), per-plan contents (floor plan image, room sizes, free PDF/DXF/IFC/GLB downloads), and the return shape (plan cards linking to the plan page and CAD studio). It also advises that filters are optional, adding behavioral context beyond structured fields.

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 trigger condition, followed by library/return details and a filter-usage note; every sentence carries information. The download-format enumeration is slightly dense but still earns its place by telling the agent what users get.

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?

For an 8-parameter filtered search with an output schema already present, the description covers purpose, trigger, result shape, and filter behavior – more than enough for correct invocation. Nothing an agent needs 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 88%, so the schema documents nearly every parameter, and the description correctly doesn't repeat those details. It does add one useful semantic point – that all filters are optional and should only be applied when the user asked – which is guidance the schema cannot convey.

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+resource (search a library of ~500 free house plans) and adds concrete examples of query intent plus what each plan contains. An agent can distinguish this from get_house_plan (single plan) and from the CAD-drawing siblings without opening any 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?

Opens with an explicit trigger ('Use this when the user wants ready-made house plans...') and gives illustrative example queries, so the when-to-use condition is unambiguous. The one gap is it never names a sibling alternative or a when-not-to-use case (e.g., fetching a known plan via get_house_plan), which keeps it short of a 5.

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