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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds meaningful extras beyond the annotations: 'Live', 'no local context', and 'Paid per call' — useful behavioral context for an agent deciding whether to invoke it.

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?

Two short sentences front-load the core behavior and then add only non-redundant, decision-relevant traits: live data, CoinGecko source, read-only, no local context, and paid per call. No filler or repetition of schema details.

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?

For a simple read-only tool with two fully documented parameters and no required fields, the description plus annotations are sufficient. The lack of an output schema is slightly mitigated by the phrase 'prices', which communicates roughly what the tool returns, though an explicit return-structure note would make it 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%, with clear parameter descriptions and an example for ids. The description mostly restates what the schema already says about vs_currency and multi-coin support, without adding new syntax, defaults, or format details. Baseline 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 uses a specific verb ('get prices') and a specific resource ('crypto token prices via CoinGecko'), clarifying that it returns live market prices for one or more coins. It is clearly distinct from siblings like paid_convert or paid_model_price because it narrows scope to token price quotes.

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 implies the use case: fetch live crypto prices in a chosen quote currency. However, it does not explicitly say when not to use it or point to alternatives, such as paid_convert for conversions. The usage context is clear but not fully differentiated from related tools.

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