REI Crypto MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states it's a GET operation for historical data, implying read-only behavior, but doesn't cover important aspects like rate limits, authentication needs, data freshness, pagination, or error handling. For a data retrieval tool with zero annotation coverage, this is insufficient.

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 very concise with just two lines: the endpoint path and a brief explanation. It's front-loaded with the key information (GET operation and historical AUM focus). While efficient, it could potentially benefit from slightly more detail without becoming verbose.

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 has 0 parameters, 100% schema coverage, and an output schema exists, the description is minimally complete. However, for a historical data retrieval tool with no annotations, it lacks context about data format, time ranges, or comparison to siblings. The output schema helps, but the description itself is too sparse for full completeness.

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 input schema has 0 parameters with 100% description coverage, so the schema fully documents the absence of parameters. The description doesn't need to add parameter information, and it doesn't contradict the schema. A baseline of 4 is appropriate since no parameters exist and the schema coverage is complete.

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 the tool retrieves historical AUM (Assets Under Management) data for BTC ETFs, which is a specific verb ('GET') and resource ('historical AUM of all BTC ETFs'). It distinguishes from some siblings like 'get_etf_overview' or 'get_etf_history_eth', though not all siblings are directly comparable. However, it doesn't explicitly differentiate from all similar tools, keeping it at a 4 rather than a 5.

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 no guidance on when to use this tool versus alternatives. It doesn't mention when-not scenarios, prerequisites, or compare it to siblings like 'get_etf_history_eth' (for ETH ETFs) or 'get_etf_overview' (for overview data). This lack of contextual usage information results in a low score.

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