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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description earns credit for disclosing a non-obvious data trait: the Toman figures are computed from the ounce and dollar rate and omit Tehran market premium/making charges, with an explicit instruction to disclose this to users. Freshness and update cadence are not mentioned.

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 English sentence front-loads the data scope, then the critical computed-vs-market caveat, then the disclosure instruction — a sensible priority order. The bilingual restatement adds tokens but serves a real audience; otherwise there is no filler.

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 input params, no nested objects and no output schema, the description carries the burden of describing returns, and it does enumerate the units and instruments (ounce/USD, per-gram 18k Toman, mesghal, coins). It stops short of stating freshness, whether values are cached, or the exact response shape, which an agent quoting live prices would want.

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, which is the baseline-4 case; there is nothing to disambiguate. The description correctly implies a single no-argument snapshot call rather than a filtered query.

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 the exact resources returned: global gold and silver ounce in USD plus Toman values for 18k gold per gram, mesghal and coins. That is far more specific than the title, which merely says 'Gold and silver'. It does not explicitly contrast with siblings like get_rate or convert, but the precious-metals scope is self-evidently distinct.

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 only implied — the reader infers this is the tool for gold/silver quotes. The one concrete directive, 'say so when you quote them', tells the agent how to present results rather than when to pick this tool over get_rate or convert. No exclusions or prerequisites are stated.

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