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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false, destructiveHint=false). The description adds only the word 'Estimate', implying an approximate result, but omits details such as whether taxes, fees, or insurance are included.

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 sentence, front-loaded with the purpose, followed by a compact list of inputs. There is no filler or repetition, and every element helps identify the calculation.

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 with full schema coverage and no output schema, the description states the return value (monthly payment) and the major inputs. Minor gaps remain, such as not mentioning the default term of 60 months or that the estimate excludes taxes/fees, but these are largely covered by the schema.

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 fully documents each parameter. The description merely lists parameter names (price, down, trade, term, APR) without adding format, constraints, or defaults beyond what the schema already provides.

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 ('Estimate') and resource ('monthly auto-loan payment'), and lists the relevant inputs. It clearly distinguishes this tool from sibling loan calculators like boat_loan and mortgage_payment.

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?

Provides no when-to-use or when-not-to-use guidance, and does not name alternatives such as boat_loan or mortgage_payment. The agent must infer usage solely from the tool name and the auto-loan framing.

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