CoinGecko MCP Server

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

The annotation readOnlyHint=true already indicates this is a safe read operation. The description adds useful context about what data is returned (metadata and market data from CoinGecko) and the specific lookup method (contract address + platform), which goes beyond the annotation. However, it doesn't disclose behavioral traits like rate limits, authentication needs, or pagination. With annotations covering safety, a 3 is appropriate as the description adds some value but not comprehensive behavioral context.

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, well-structured sentence that efficiently conveys the tool's purpose, scope, and key parameters. It uses bolding for emphasis without being excessive. While it could be slightly more concise by removing 'This endpoint allows you to', the information density is high with zero wasted words.

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 moderate complexity (2 required parameters, no output schema, read-only operation), the description adequately covers the what and how but has gaps. It explains the data returned and lookup method, but doesn't address parameter formats, error conditions, or response structure. With no output schema and 0% schema coverage, the description should do more to compensate, making it minimally viable but incomplete.

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 schema description coverage is 0%, meaning neither parameter (id, contract_address) has descriptions in the schema. The description mentions 'asset platform and a particular token contract address', which partially explains the parameters but doesn't specify that 'id' corresponds to the asset platform or provide format examples. It adds some meaning but doesn't fully compensate for the complete lack of schema documentation.

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 explicitly states the verb 'query' and specifies the resources: 'metadata (image, websites, socials, description, contract address, etc.) and market data (price, ATH, exchange tickers, etc.) of a coin'. It clearly distinguishes this tool from siblings by focusing on contract-based coin data retrieval, unlike tools like get_coins_markets (general market data) or get_id_coins (ID-based queries).

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 provides clear context for usage: 'based on an asset platform and a particular token contract address'. It implies this tool is for contract-specific queries, but does not explicitly state when NOT to use it or name alternatives like get_id_coins for non-contract-based queries. The context is sufficient but lacks explicit exclusions or named alternatives.

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