Gold and coin prices

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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds real behavioral context beyond that: the period semantics of gold18_day_change_pct vs gold18_period_change_pct/low/high, and critically that a null coin price means 'not for sale right now'. That null-value meaning is not something annotations would convey.

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 sentences, front-loaded with the core purpose and scope, then field semantics. Every sentence carries information. The second sentence is dense with field names, but nothing is filler or redundant.

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?

An output schema exists, so return structure needn't be spelled out. The description nonetheless supplies interpretation rules (change_pct period undocumented for coins, null = unavailable) that an agent needs to read the output correctly. Missing only explicit usage/routing guidance and any freshness/cadence note beyond 'live'.

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?

Zero parameters, so by the rubric this is a baseline 4. The description does define the meaning of returned fields (day vs period change, null price semantics), which is beyond the no-parameter schema and helps interpretation, though these are response fields rather than inputs.

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: 'Get Digikala's live 18k gold price per gram and gold coin prices, in Toman.' No sibling tool in the list deals with gold/coins, so it is trivially distinguishable from dk_search, dk_product, dk_price_history etc. An agent knows exactly what this returns.

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 agent infers 'call this for gold/coin prices' from the purpose statement. There is no explicit when-to-use or when-not-to-use guidance, nor a pointer to dk_price_history as the historical alternative for other assets. The implicit '~3-month chart' reference hints at the covered window but does not route the agent anywhere.

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