Financial Modeling Prep MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions 'real-time aftermarket quotes' and the API source, but lacks details on rate limits, authentication needs, error handling, or response format. For a tool with no annotations, this leaves significant gaps in understanding how it behaves operationally.

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 concise and well-structured in two sentences. The first sentence states the core purpose and API source, while the second elaborates on the data tracked and context. There's no wasted verbiage, and it's front-loaded with key information, though it could be slightly more efficient by integrating the context into the first sentence.

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 complexity (real-time data access), lack of annotations, and no output schema, the description is incomplete. It doesn't explain what the return values look like, potential limitations (e.g., data availability, latency), or how it differs from similar tools. For a tool with no structured behavioral or output information, more descriptive context is needed.

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 100% description coverage, with one parameter 'symbol' clearly documented as 'Stock symbol'. The description doesn't add any additional parameter semantics beyond what the schema provides, such as format examples or constraints. With high schema coverage, the baseline score of 3 is appropriate as the schema does the heavy lifting.

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's purpose: 'Access real-time aftermarket quotes for stocks' with the FMP Aftermarket Quote API. It specifies the resource (stocks) and verb (access quotes), and mentions key data points like bid/ask prices and volume. However, it doesn't explicitly differentiate from sibling tools like 'getAftermarketTrade' or 'getQuote', which reduces clarity.

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 minimal usage guidance. It mentions tracking data 'outside of regular trading hours', which gives some context about when this tool is relevant, but it doesn't specify when to use this versus alternatives like 'getAftermarketTrade' (for trades) or 'getQuote' (for regular hours). No explicit alternatives or exclusions are provided.

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