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

Annotations already declare read-only, idempotent and non-destructive behavior, so the bar is lower; the description still adds real value beyond them — the cost (1 request unit), plan availability including free, Turkish-language JSON, and the presence of source and 'guncelleme' timestamp fields. Only the response shape itself is left unspecified.

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 tight sentences: the payoff (what you get) is front-loaded, and the endpoint/cost/language details follow compactly. No filler or repetition 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 no output schema, the description carries the burden of explaining returns, and it does — classes, effective date, source and update fields, language. A brief note on the response envelope structure would close the remaining gap, but an agent has enough to call it 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?

The tool takes zero parameters, so the baseline is 4; the description nonetheless clarifies what the returned data is sliced by (vehicle classes 1–6, effective date, class definitions), which compensates for the absent output schema.

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 ('Returns current toll prices in TRY by vehicle class') plus the exact scope: 22 motorway routes, the Bosphorus bridges and the Eurasia Tunnel. The vehicle-class enumeration and the endpoint path make it immediately distinguishable from the fuel-price, FX and other sibling tools.

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 gives context (all plans including free, 1 request unit per call) but never says when an agent should reach for this tool versus the many other data siblings, nor any exclusions. Usage is implied by the subject matter alone rather than stated.

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