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

With no annotations, the description carries the full burden and does well: it discloses PostGrid address verification, content screening, price-quote return, the never-mails guarantee, and the needs_review fallback when PDF text extraction fails. It omits auth/permission requirements and any rate or cost caveats beyond what the schema's certified description covers.

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?

Two short paragraphs, front-loaded with the core behavior and the critical never-mails constraint. No filler, though the PDF extraction sentence is a slight tangent from the main draft-purpose statement.

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?

An output schema exists so return values need not be explained, and the description covers the draft workflow, screening, and failure flagging well. It could be fuller on what the draft object/quote contains or the lifecycle toward request_send, but it is largely complete for a 9-parameter tool.

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 all nine parameters are already documented in the schema, including the html-OR-pdf_path exclusivity. The description restates that mutual exclusivity and adds the PDF-extraction screening consequence, but mostly reinforces schema content rather than adding new parameter meaning.

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+resource ('Create a letter DRAFT') and immediately names the side effects it performs (address verification, content screening, price quote). The emphatic 'This NEVER mails anything' distinguishes it from the send-oriented siblings request_send and send_status without needing to name them.

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?

Clearly explains the html-vs-pdf_path choice and the never-mails scope, which implies this is the pre-send step. It stops short of explicitly naming request_send as the follow-up action, so the routing to alternatives is implied rather than stated.

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