Live crypto spot-price snapshots in USD for requested CoinGecko ids, with 24h change. Pass comma-separated ids (max 20); defaults to bitcoin,ethereum. [PAID: $0.015 USDC per call via x402]
| Name | Required | Description | Default |
|---|---|---|---|
| ids | No | Comma-separated CoinGecko ids, max 20 (e.g. bitcoin,ethereum,solana) |
Changes observed during successful MCP inspections.
Input schema / additionalPropertiesPrevious value: -trueNew value: +falseInput schema / properties / idsAdded value: +{
+ "description": "Comma-separated CoinGecko ids, max 20 (e.g. bitcoin,ethereum,solana)",
+ "type": "string"
+}Input schema / properties / promptRemoved value: -{
- "description": "Input prompt for this service.",
- "type": "string"
-}Input schema / requiredPrevious value: -[
- "prompt"
-]New value: +[]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does disclose two non-obvious traits: a hard cap of 20 ids and a paid model ($0.015 USDC per call via x402), which materially affects invocation. It does not cover error handling, rate limits, or freshness guarantees.
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 compact sentences: capability and payload first, then the calling convention and default, then the pricing tag in brackets. Every clause earns its place with no filler.
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 zero-required-param read tool with no output schema, the description conveys what is returned (USD spot price plus 24h change), the id format, the cap, the default, and the payment requirement. Only error/edge-case behavior is left unspecified, which is a minor gap.
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% for the single 'ids' parameter, so the baseline is 3. The description adds value beyond the schema by stating the default ('bitcoin,ethereum'), which the schema does not declare (required is empty and no default is specified), plus the same 20-id cap.
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+resource ('Live crypto spot-price snapshots in USD'), the data source ('CoinGecko ids'), and the payload detail ('with 24h change'). No sibling overlaps with this function, so differentiation is moot and the purpose is unambiguous.
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?
Gives the calling convention ('Pass comma-separated ids (max 20)') and the fallback behavior ('defaults to bitcoin,ethereum'), which is clear operational context. It stops short of explicit when-to-use/when-not guidance, though no sibling tool competes for this task.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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