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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the overwrite semantics are partly conveyed structurally. The description adds scope ('only the user's own') and bounds (at most 168), but does not state that it replaces any prior capacity, whether the change is reversible, or auth requirements.

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?

A single dense sentence with the core action front-loaded and constraints following; no filler or repetition.

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 one-parameter tool whose annotations already cover the safety profile, the description supplies scope, valid values and limits. No output schema exists so return-value explanation is not required; only minor gaps like invalid-input behavior remain.

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%, so baseline is 3, but the description adds real meaning beyond the schema: canonical example values (40, 37.5, 37:30), the special case 0 meaning away, and the upper bound of 168. This enriches the single 'hours' parameter meaningfully.

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 precise verb+resource: setting the user's own weekly capacity hours, and explains its downstream purpose (comparison against planned work in the workload view). The line 'Only the user's own: there is no way to set another person's' effectively carves it out from team/member-management siblings.

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?

Provides value-context guidance ('0 for someone who is away, at most 168') that helps an agent pick an appropriate input, and ties the field to the workload view. However, it never states when to call this versus alternatives such as update_member, nor any prerequisites.

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