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

With no annotations, the description carries the full behavioral burden and does a solid job: it declares the operation read-only, explains the return payload structure (base64 content plus name and mime type), and discloses the 5 MB size ceiling. It stops short of covering auth, not-found behavior, or response size implications, but it adds meaningful context beyond the schema.

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?

One sentence, front-loaded with the return format, then the size constraint, then the read-only trait. Every phrase supplies information an agent would want, with no repetition or filler.

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 two-parameter read-only getter with a fully described input schema and no output schema, the description is nearly complete: it explains the return shape, limit, and safety profile. The only meaningful omission is workflow context, such as pointing to crm_list_lead_documents for finding document IDs.

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%, and both parameters are fully documented as UUIDs in the schema. The description adds no further parameter meaning beyond the implied relation that document_id identifies the file. Baseline 3 is appropriate when the schema already does this work.

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 states a specific action and result: it returns a lead document's file as base64 along with name and mime type. That clearly separates it from upload/list/delete document siblings, though it does not explicitly name any sibling or say 'download a single document by ID.'

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?

It gives one concrete usage constraint: files up to 5 MB are supported, and larger files must go through REST. However, it does not explain when to call this versus crm_list_lead_documents, nor does it mention how to obtain the required document_id. Usage guidance is implied rather than explicit.

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