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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds two genuinely new behavioral facts not in the annotations: a paid subscription is required and each call consumes 2 request credits, plus the underlying endpoint GET /v1/altin. That cost/quota disclosure is exactly the kind of context annotations cannot express.

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 short and front-loads the identity of the resource, then the endpoint and billing constraints. The only inefficiency is the opening line duplicating the tool title verbatim, which spends a sentence without adding information.

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 one-optional-parameter read tool with annotations and no output schema, the cost and endpoint disclosures cover the most important unknowns. Still missing are the set of acceptable 'tur' values, the default when the parameter is absent, and any indication of how this differs from altin_gecmis, leaving the agent to guess on the only input it must supply.

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 single 'tur' parameter is already documented as a comma-separated list of types (e.g. gram, ceyrek). The description adds nothing further and, notably, gives no enumeration of valid types and no default behavior when 'tur' is omitted — but with full schema coverage the baseline of 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 states the resource ('Altın fiyatları' with alış/satış/değişim), so an agent knows it returns current gold buy/sell prices and change values. However, the first sentence is a verbatim restatement of the title, and nothing distinguishes it from the sibling altin_gecmis (historical gold prices), which is the main ambiguity an agent faces here.

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?

There is no explicit when-to-use or when-not guidance, and no routing to altin_gecmis for historical data. The only conditional information is a prerequisite ('Ücretli paket gerekir'), which is helpful but is a cost gate, not selection guidance.

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