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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely useful behavioral content beyond that: the report is produced in both cash and accrual views and covers both hours/earnings and invoice issuance/payment status, which tells the agent what the call will and won't include.

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?

It is a single front-loaded sentence with no filler, and the breakdown dimensions are listed compactly. The colon-fragment style is dense but readable; nothing needs to be cut.

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 one required parameter, an output schema to describe the return shape, and annotations covering the safety profile, the description only needs to convey scope — which it does (dimensions, both accounting bases). The lack of explicit routing guidance against sibling aggregation tools is the only real gap.

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 a single parameter and schema description coverage is 100%, with the schema already giving the calendar-year meaning, the 2000-2100 range and an example. The description adds no additional semantics for 'year' beyond what the schema supplies, so the baseline 3 applies.

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?

The description names the resource (one calendar year) and enumerates exactly what it reports: hours and earnings broken down by quarter, month, client and project, plus invoice status. That is specific enough to distinguish it from aggregate siblings like project_totals, though it never names an alternative explicitly.

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?

Usage is only implied by the title 'Year summary for taxes' and the annual scope of the description; there is no statement of when to choose this over project_totals or list_entries, and no exclusions or prerequisites. An agent can infer the tax/annual-reporting context but must guess the boundary against sibling aggregation tools.

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