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

With no annotations, the description carries full burden. It discloses the cost model and source, but omits behavioral traits like rate limits, caching, error handling for invalid IDs, or explanation of the 'confidence' field. The cost disclosure is valuable, but overall transparency is moderate.

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 a single, front-loaded sentence that efficiently conveys purpose and cost. No unnecessary words, though a slightly more structured format (e.g., listing fields separately) could improve readability.

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 simple tool (one optional param, no output schema), the description is functional but lacks completeness. It doesn't explain the return format or provide an example call. The tool's simplicity reduces the need for extensive detail, but the description could still be more helpful.

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 coverage is 100% with the 'coins' param well-documented. The description adds marginal value by restating 'CoinGecko ids' but doesn't elaborate on default behavior or format beyond what the schema already provides. 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 it provides live spot token prices with specific fields (price, change_24h, etc.) for CoinGecko IDs from DefiLlama. While it distinguishes the tool as a full prices tool, it does not explicitly differentiate from the sibling 'crypto_prices_preview', missing an opportunity to clarify when to use each.

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 mentions the cost ($0.005 per call) but provides no guidance on when to use this tool versus alternatives like 'crypto_prices_preview'. No exclusions or context for optimal use are given, leaving the agent to guess.

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