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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false. The description adds real value beyond them: it discloses the admin authorization requirement and clarifies that the change only affects users without their own preference, so it implicitly reassures that existing personal choices are untouched.

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?

Two short sentences, front-loaded with the action and effect, with no filler. Density is appropriate, though the brevity comes at the cost of documenting the parameters.

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 mutation tool with four parameters, no output schema, and zero schema description coverage, the description leaves significant gaps: the meaning of message_type and its enum, the role of idempotency_key/request_id, and what the response looks like are all undocumented.

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 description coverage is 0% with 4 parameters, so the description must compensate. It mentions only the channel concept; message_type, request_id, and idempotency_key are never explained, and the description does not say whether channel applies per message_type or globally.

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: setting the default notification channel at the organization level. The scope ('for people who have not chosen their own') distinguishes it conceptually from a personal preference setter, though it never names the sibling yardstick_notifications_set or yardstick_notifications_org_defaults_get.

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?

'Admins only' gives the permission prerequisite and the phrase 'for people who have not chosen their own' implies when the default applies. However, there is no explicit routing guidance versus yardstick_notifications_set or yardstick_notifications_org_defaults_get, leaving the agent to infer which tool to use.

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