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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds the output details (depreciation and remaining book value) and the 'for a given year' scope, but does not disclose edge cases or assumptions. No contradiction.

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 concise sentences front-load the method and output without any filler. Every phrase adds value.

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 simple calculator tool with well-documented schema and an output schema, the description is sufficient. It specifies the method, the year scope, and the return values. Missing explicit edge-case handling but not required.

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?

The input schema provides complete descriptions for all three parameters (value, ratePct, year) at 100% coverage. The description adds the conceptual context of 'fixed percent of reducing book value' but no additional syntax or format specifics.

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 clearly states the tool computes declining-balance depreciation using a fixed percentage of reducing book value for a specified year and returns both that year's depreciation and remaining book value. This specific method definition distinguishes it from sibling tools like straight-line or double-declining.

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?

The description implies usage by defining the method, but does not explicitly state when to choose this over alternatives such as straight-line-depreciation or double-declining-depreciation. It lacks explicit when/when-not guidance.

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