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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description is not required to restate it. It adds genuinely useful behavior: output is text-only/non-interactive, and partial preference input is tolerated rather than required. It stops short of describing result content, but an output schema exists to cover that.

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?

Three sentences, front-loaded with the core behavior before the routing rules. Every clause carries decision-relevant content; the final sentence is slightly redundant with the second but serves as a useful guard against a specific mis-selection.

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 a 13-parameter, all-optional tool with an output schema and rich annotations, the agent has everything needed: what it returns, what input it accepts, and precisely when to choose it over the sibling. Nothing material 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% with enum values and per-field descriptions, so the baseline is 3. The description adds real meaning by clarifying that all 13 fields are optional and the tool will recommend based on whatever subset is known — semantics the schema's 'required: []' implies but does not state as intent.

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 and resource ('Returns a quick, text-only boat type recommendation') and explicitly declares its scope: works with however many preferences are known, all fields optional. It directly names and contrasts with the sibling boat-quiz, so an agent can distinguish the two without opening 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?

Gives explicit when-to-use conditions (user asks for a fast non-interactive answer, or the client cannot render interactive content), a when-not with a named alternative (prefer boat-quiz in every other case), and even pre-empts a likely misuse ('having fully known preferences is not by itself a reason to use this tool'). This is exemplary routing guidance.

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