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

No annotations are provided, so the description carries the full burden. It does disclose that data is real-time and includes post-market trade prices, volumes, and timestamps. However, it does not mention output structure, any limitations, or whether the response is keyed by symbol, which would be valuable 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 two sentences long, front-loaded with the main verb and resource, and contains no redundant phrasing. Each sentence adds value: the first states the core action, the second elaborates on the data fields.

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 one-parameter batch retrieval tool with no output schema, the description adequately covers the input and the returned data elements (prices, volumes, timestamps). It could be slightly more complete by clarifying whether the response is an object keyed by symbol or an array, but this 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?

The schema already provides a 100% clear description for the only parameter: 'Comma-separated list of stock symbols'. The description adds no new semantic details beyond paraphrasing with 'multiple stocks' and 'several companies', so it does not enhance the schema's coverage.

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 verb 'Retrieve' and the resource 'real-time aftermarket trading data for multiple stocks'. It specifically mentions the FMP Batch Aftermarket Trade API and distinguishes itself from siblings like getAftermarketTrade (singular) and getBatchAftermarketQuote by emphasizing 'trade data' and 'across several companies simultaneously'.

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 batch use case by saying 'for multiple stocks' and 'across several companies simultaneously', but it does not explicitly mention when to use this tool versus alternatives like getAftermarketTrade or getBatchAftermarketQuote, nor does it provide exclusion criteria.

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