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

Annotations already declare the tool as read-only, idempotent, non-destructive, and closed-world. The description adds substantial domain behavior: it explains the GVWR bands, year-specific caps, bonus depreciation treatment, and business-use scaling. It does not describe the return structure, but the annotations carry the safety profile.

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?

The description is front-loaded with the core purpose and then supplies dense, relevant detail. It is a long run-on sentence, but every clause contributes useful tax-rule context rather than filler.

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 read-only lookup tool with a fully described schema, the description is largely complete: it covers the key thresholds, years, caps, and business-use rule. Because there is no output schema, it could say more about the return shape, but the core behavior is sufficiently explained.

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 100%, so the schema already documents all six parameters. The description adds meaning beyond the schema by mapping GVWR ranges to specific cap regimes and by explaining how tax year, bonus eligibility, exempt status, and business use affect the result. It does not mention the cost parameter, but the schema covers it.

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 states a specific verb and resource: it returns first-year write-off limits for a business vehicle by GVWR. It is clear what the tool does, but it does not explicitly distinguish itself from sibling calculation tools such as calculate_section_179 or calculate_bonus_depreciation.

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 implied by the GVWR thresholds and the business-use rule, but the description does not say when to use this tool versus the sibling calculation tools. It also does not state exclusions or prerequisites beyond the more-than-50% business use rule.

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