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

Annotations already declare non-read-only, idempotent, non-destructive, closed-world, but the description adds substantial context beyond them: partial-update semantics, the fact that list fields are replaced wholesale, that unrecognized skills are silently dropped, and that the response echoes what was kept. The auth requirement (personal access token) is also called out. It stops short of describing error behavior if the token is missing.

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?

Four tight sentences, front-loaded with the mutation model before the validation caveat and the usage constraint. Dense but every clause carries information; the final permission sentence is slightly orphaned from the rest.

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 explained, and the description still notes the response reports retained values. With 10 optional parameters, the description supplies the two things that matter most: partial-update behavior and the read-before-write workflow.

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 80%, so field meanings and formats are largely handled by the schema. The description nonetheless adds the crucial semantic the schema omits: providing a list field replaces rather than appends, which changes how an agent should construct the call. It does not clarify interactions between digest_day, digest_time, and cadence.

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: change the user's search preferences. It also implicitly separates itself from the read sibling by telling the agent to read get_preferences first, though it does not explicitly name update_alert as the alternative for alert configuration.

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 an explicit prerequisite (read get_preferences first), a scoping rule for when it should fire (only when the user asks), and the condition that selects a different tool for inspection versus mutation. Nothing is left to inference.

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