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. It effectively discloses key behavioral traits: it's a download operation (implies data transfer), specifies that files are saved locally, mentions overwrite behavior, and describes return values. It doesn't cover aspects like error handling, rate limits, or authentication needs, but provides solid operational 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 well-structured and front-loaded with the core purpose in the first sentence. Subsequent sections for parameters, returns, and example are clearly labeled and concise, with no wasted words. Every sentence serves a specific informative role.

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 (3 parameters, no output schema, no annotations), the description is fairly complete. It covers purpose, parameters, returns, and includes an example. However, it lacks details on prerequisites (e.g., job must be completed), error conditions, or file formats, which could be useful for full contextual understanding.

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%, so the baseline is 3. The description adds value by organizing parameters in a clear list with required/optional labels and default values, and provides a concrete example that illustrates usage. This enhances understanding beyond the schema's basic descriptions, though it doesn't introduce new semantic details.

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 specific verb ('Download') and resource ('completed batch job files'), and distinguishes it from siblings like 'get_batch_job_files' (which likely lists files) and 'submit_batch_job' (which initiates jobs). The phrase 'to a local directory' adds useful context about the destination.

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 usage by mentioning 'completed batch job files', suggesting this tool should be used after a batch job finishes. However, it doesn't explicitly state when to use it versus alternatives like 'get_batch_job_files' (which might retrieve metadata) or provide clear exclusions. The context is implied but not fully explicit.

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