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

Annotations give destructiveHint=false and openWorldHint=false, so the safety profile is partly covered, and the parenthetical '(live product metric)' adds that the value is computed live rather than cached. However, readOnlyHint=false is left unexplained for what reads as a pure computation, and the description does not clarify this tension or the return shape.

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 front-loaded sentence with no waste. The trailing parenthetical is slightly vague but short enough to earn its place as a liveness hint.

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?

With no output schema, the description should say what is returned (e.g., a fraction or percentage of the year elapsed), but it never does. An agent can call it with the required timezone but cannot predict the response.

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?

There is only one parameter and schema coverage is 100%, with an IANA timezone example already documented in the schema. The description adds only that the timezone scopes the computation, which is the baseline expectation.

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+resource ('Compute calendar year progress') scoped to a timezone, which no sibling tool covers. Clear to an agent, though the exact output measure (percentage elapsed versus days remaining) is not specified.

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?

No guidance on when to call this versus alternatives, nor any prerequisites or exclusions. The sibling list contains nothing similar, but the description never states the use case or trigger condition.

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