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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds domain behavior beyond that: the agency exclusion rules for installment debts and utilization thresholds. It does not disclose what the simulation returns, time horizon assumed, or how ties between strategies are resolved.

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 dense sentence with no filler, front-loading the three compared strategies. The clause about thresholds is somewhat compressed and jargon-heavy, which slightly hurts readability, but nothing is redundant.

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 simulation with 6 well-documented parameters but no output schema, the description should say more about what the simulation produces (comparison table, months-to-payoff, DTI trajectory). It covers inputs and strategy choice adequately but leaves the result shape entirely unstated.

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 every parameter is already documented including defaults and enums. The description restates the targeting logic tied to the debts array and alludes to utilization/DTI inputs, but adds no syntax or interpretation guidance beyond the schema, so 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 a specific verb (simulates) and three concrete strategies (Avalanche, Snowball, DTI-First), plus the targeting rule (installment debts near <=10 remaining payments, revolving cards above 30%/10% utilization). It does not explicitly distinguish itself from siblings like calculate_mortgage_dti or evaluate_loan_readiness_score, so it falls short of a 5.

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 strategy names and the mortgage-readiness framing, and the debt-targeting thresholds hint at the scenario the tool is for. However, there is no explicit when-to-use or when-not-to-use statement, and no pointer to the sibling tools (e.g. use calculate_mortgage_dti for a single DTI snapshot vs this for multi-strategy payoff comparison).

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