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

With no annotations, the description carries the burden well: it discloses that the rate applies forward from effective_from (default now) and that already-kept time retains its original rate, which is the non-obvious, quasi-immutable behavior an agent must know before mutating. It omits whether the call is idempotent or whether a write scope beyond see_costs is required, so it falls short of a 5.

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 compact sentences with the scoping suffix ('Owner or office') front-loaded and no filler. The forward-application sentence is slightly tangled in phrasing ('to time kept after that') but every clause carries information.

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 values need not be described; the description instead covers the mutation's effect on existing time, permission requirements, and default/reset semantics. Minor gaps remain around units and whether payroll reporting consumes the new rate.

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%, so the description must compensate, and it explains the two non-obvious parameters: person_id omission targets the shop default, and null cost_per_hour_minor resets a worker to that default. effective_from's default and forward-only application are stated. It leaves shop_id and the minor-unit/range semantics (min 0, max 100000000) unaddressed.

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: set the hourly cost rate (wage plus burden) for a worker, or the shop default when person_id is omitted. It clearly separates the per-person case from the shop-default case, which lets an agent distinguish it from the read-only sibling timesheets_listRates.

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 the caller role (owner or office) and a hard precondition (needs see_costs), plus the rule that omitting person_id edits the shop default. It does not name timesheets_listRates as the way to inspect current rates, so routing to the alternative is left implicit.

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