New-car market prices

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

Annotations already declare read-only, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds real context beyond that: currency (Toman), daily refresh cadence, and a coverage caveat that only variants Karnameh currently prices appear. It stops short of describing how results are ordered or how the price-source field looks, so it is strong but not exhaustive.

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?

Three short sentences, front-loaded with the resource and source URL, then usage, then routing to alternatives. No filler and no restatement of the title.

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 nine optional params, no output schema and no required fields, the description supplies what the schema cannot: what a row represents, units, freshness, and coverage limits. Pagination is left to the schema's `page` description, so the remaining gap is minor.

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 one of the nine parameters is already documented in the schema and the baseline of 3 applies. The description adds only the unit confirmation (Toman) and the note that rows carry a `name` usable with kn_price_history, without new syntax or filter-interaction guidance.

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 and resource ("list today's market prices of new zero-km cars") and names the data source (karnameh.com/car-price). It also scopes the output shape (each row is a variant plus production year with price sources), which lets an agent distinguish it from kn_latest_prices and kn_price_history 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?

Gives explicit when-to-use phrasing ("how much is a new X", compare models) and names both alternatives with the condition that selects each: kn_latest_prices for discontinued/older models, kn_price_history for movement over time. It also states an exclusion (no Peugeot Pars or 405), which prevents a wrong call.

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