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

Annotations already cover safety (readOnlyHint, destructiveHint, idempotentHint, openWorldHint). The description adds the caveat that data is 'indicative market data, not financial advice' and calls the data 'curated', providing useful context about data trustworthiness. However, it does not describe response structure or pagination (though an output schema exists), so it does not go beyond a moderate level of added transparency.

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 description is two sentences: the first clearly states the tool's purpose, and the second adds a necessary disclaimer. It is concise, front-loaded, and contains no fluff.

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?

Given the tool's simplicity (1 optional parameter, output schema present, strong annotations), the description covers the core purpose, currency scope, and data caveat. It lacks explicit sibling differentiation, but the tool name and description sufficiently convey the crypto-specific use case. This is nearly complete for a read-only list tool.

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 input schema fully describes the single 'symbols' parameter (100% coverage), so the description does not need to add parameter context. It neither repeats nor enhances the schema, thus the baseline score of 3 is appropriate.

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 clearly states the tool's function: 'Returns latest curated Arzbin crypto prices in Toman and USD.' It uses a specific verb ('returns'), specifies the resource ('crypto prices'), and includes currency details, distinguishing it from sibling tools like get_latest_fiat_rates or get_latest_gold_rates.

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 indirectly implies usage by stating 'crypto prices', which differentiates it from fiat and gold rate tools, but it does not explicitly mention alternatives or provide when/when-not guidance. The intended use is clear from context, but no exclusions or alternative tool references are given.

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