Databento MCP

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. While 'export' implies a write operation, the description doesn't mention important behavioral aspects like whether this is a synchronous or asynchronous operation, potential file size limitations, authentication requirements, rate limits, or what happens if the output path already exists.

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 communicates the core functionality without any wasted words. It's appropriately sized and front-loaded with the essential information.

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 tool with 7 parameters, no annotations, and no output schema, the description is insufficiently complete. It doesn't explain what the tool returns (e.g., success/failure status, file metadata), doesn't mention performance characteristics or limitations, and provides no context about how this fits with sibling tools in the data processing workflow.

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, providing clear documentation for all 7 parameters. The description adds no additional parameter information beyond what's already in the schema, so it meets the baseline of 3 for adequate but not exceptional parameter semantics.

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 with a specific verb ('Query historical data and export') and resource ('to Parquet format'), making it easy to understand what the tool does. However, it doesn't explicitly differentiate from sibling tools like 'get_historical_data' or 'convert_dbn_to_parquet' which might have overlapping functionality.

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. With sibling tools like 'get_historical_data' (which likely retrieves data without export) and 'convert_dbn_to_parquet' (which converts existing files), there's clear potential for confusion about when this specific export tool is appropriate.

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