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

With no annotations, the description carries the burden for behavior. It frames the tool as a calculator that 'sees' savings, implying a read-only computation, but does not disclose assumptions or side effects. Since calculators are inherently non-mutating, it is adequate but lacks explicit detail.

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 state the purpose and key inputs without redundancy. The description is front-loaded and 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?

With 6 required parameters, no output schema, and no annotations, the description is too brief to fully specify behavior. It does not explain calculation assumptions, output format, or the role of all parameters, making it incomplete for an agent to invoke correctly.

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 has 0% description coverage, so description must explain parameters. It mentions fee, promo months, and planned payment, corresponding to transferFeePct, promoMonths, and monthlyPayment, but omits balance, currentAprPct, and revertAprPct. The mappings are not explicit, and key inputs like revertAprPct are left unexplained.

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 compares 0% balance transfer savings versus current APR, with specific inputs. It distinguishes from sibling calculators like credit_card_payoff_calculator by focusing on balance transfer scenarios.

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 the use case: evaluating a balance transfer offer versus keeping current APR. It provides context but does not explicitly mention alternatives or exclusions, so 4.

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