alpaca-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 SIP data' but doesn't specify rate limits, authentication requirements, data freshness, or error handling. For a tool fetching real-time market data, this lack of operational context is a significant gap.

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, efficient sentence that front-loads key information: action, resource, and data source. There is no wasted verbiage, and it directly communicates the tool's core function without unnecessary elaboration.

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 parameters, real-time data), the description is reasonably complete but lacks behavioral details. The presence of an output schema reduces the need to explain return values, but without annotations, more context on data sourcing and limitations would enhance completeness for safe agent use.

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 description coverage is 100%, with clear descriptions for both parameters. The description adds no additional parameter semantics beyond what the schema provides, such as explaining 'market_type' implications or 'top' behavior in more detail. Baseline 3 is appropriate as the schema adequately documents parameters.

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: 'Returns the top market movers (gainers and losers) based on real-time SIP data.' It specifies the verb ('returns'), resource ('top market movers'), and data source ('real-time SIP data'). However, it doesn't explicitly differentiate from sibling tools like 'get_most_active_stocks', which might serve a similar but distinct purpose.

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 sibling tools like 'get_most_active_stocks' or clarify scenarios where this tool is preferred, such as for real-time vs. historical data or specific market contexts. Usage is implied but not explicitly stated.

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