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

The description adds substantial behavioral context beyond the readOnlyHint annotation: the URL is one-time-use, expires after 10 minutes, is consumed on successful download, requires no Authorization header, and only works while the draft is in draft status and not expired. It also documents that fields without valid coordinates are omitted from the rendered PDF but remain in draft data.

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 dense but every sentence adds relevant information: core behavior, return format, authentication, alternative tool guidance, workflow order, coordinate rendering behavior, expiry, and state requirements. It is front-loaded with the primary purpose and contains no 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 single-parameter read-only tool with a high-coverage schema, the description is complete: it covers the return JSON fields, auth requirements, expiry and consumption semantics, valid state conditions, and how it fits into the broader preview flow. No output schema exists, so the explicit return format description is especially valuable.

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 schema already fully documents draftId with 100% coverage. The description reinforces that the ID identifies the draft to preview and ties it to the draft's status constraints, but it does not add much beyond the schema's own description.

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: gets a short-lived, one-time-use download URL for a PDF preview of a draft with signature fields rendered at coordinates. It explicitly distinguishes itself from the sibling get_draft_file by noting it returns a clickable URL rather than an embedded resource.

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?

Explicitly says when to use this tool ('when the MCP client should hand the user a clickable link') and when to prefer an alternative ('If the client can render PDFs inline, prefer get_draft_file'). It also provides a typical preview flow involving create_draft, get_draft_file_url, update_draft, and send_draft, giving clear context.

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