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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is clear. The description adds valuable context beyond annotations: the data source (CoinGecko), exact return structure, and rate limit. It does not cover error handling or unsupported symbols, but for a simple read-only tool, this is sufficient.

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 dense but well-structured: it starts with purpose, then lists supported assets, gives a use case, presents the return format, and ends with the rate limit. It is longer than necessary because the return format duplicates the output schema, but each sentence contributes useful information. 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?

The tool is simple with only three optional parameters, and an output schema exists. The description adds the key usage tip, supported assets, and rate limit, covering most practical needs. It could mention error behavior or offline handling, but given the low complexity and rich annotations, it is sufficiently complete.

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%, setting a baseline of 3. The description enhances this by noting that any CoinGecko ID is accepted, not just the listed symbols, and by clarifying the query parameter's flexibility. This adds semantic meaning beyond the schema's syntax-focused descriptions.

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 opens with a specific verb and resource: 'Live crypto price feed via CoinGecko. Returns real-time USD price and 24h change.' It clearly defines the tool's function and lists supported assets, differentiating it from other tools like x711_get_latest_gas_station and x711_tx_simulate.

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 a concrete usage context: 'Use before tx_simulate to get current gas cost in USD.' It also mentions the free tier limit (10 calls/day) and no API key needed, providing practical constraints. However, it does not explicitly compare with alternative price-related tools or state when not to use it.

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