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

Annotations already declare the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description only needs to add context beyond that. It does so usefully by disclosing the data source (the central bank's price index), the legal basis, and unit conventions, though it says nothing about edge cases such as partial payments or index revisions.

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 definition is compact, front-loaded with the legal term and rule, and every sentence carries information. The first sentence is dense but not padded, and the trailing conventions sentence is terse.

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 calculation tool with full schema coverage, the description supplies what the schema cannot: the legal basis, the index source, the meaning of the result, and the instruction to rely on the tool rather than computing manually. No output schema exists, but the description's phrasing ("what ... comes to") makes the return value clear enough.

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 five parameters, including the default for payment_year/payment_month. The description's unit note (rial, Jalali calendar) restates conventions already present in the schema, adding only marginal value. Baseline 3 is appropriate.

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 operation (calculating خسارت تأخیر تأدیه on a debt), cites the governing rule (مادهٔ ۵۲۲), and defines the computation precisely as the loss of purchasing power between the due month and the payment month. It is clearly distinguishable from the other topic-specific calculators (mehrieh, stamp duty) without opening any schema.

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?

"Call it for any question about what a late debt is worth today, and never work the figure out yourself" gives both a clear trigger condition and an explicit prohibition on doing the math manually. It stops short of naming an alternative tool or stating when-not-to-use (e.g., debts not subject to Art. 522), so it is strong but not fully exhaustive.

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