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

No annotations, so the description carries the behavioral burden and does add real information: storage is private, an activity entry is created as a side effect, and no credits are consumed. It still omits permission/auth requirements and how to undo (delete_crm_lead_document / preview variant), but the disclosed side effects and cost model are meaningful.

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?

Three tight sentences: purpose first, then a format allowlist, then behavioral notes. The long extension list is informative rather than padding, and no sentence repeats structured fields verbatim.

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 four-parameter mutation tool with no annotations and no output schema, the description covers input modes, allowed types, storage privacy, side effects, and credit cost — most of what an agent needs. Gaps remain around permissions and return/error behavior, but the core is complete.

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 coverage is 100% and already documents id, file_url, filename, and content_base64 with size limits. The description's 'base64 or https URL' and 'one file' restate the existing either/or constraint without adding format or syntax detail, so baseline 3 applies.

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?

States a specific verb and resource — 'Attach one file to a lead card' — and immediately distinguishes this from generic document tools by naming the accepted formats and the two input modes. An agent can tell this is the lead-attachment path rather than add_agent_document or upload_custom_audience.

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 when to use it (attaching a file to a lead) and constrains to one file, but gives no explicit routing to crm_list_lead_documents, crm_get_lead_document, or the preview/delete siblings. Use is inferable from the name but not stated as when/when-not guidance.

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