Create a resource proof

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

Annotations already indicate idempotent and non-destructive behavior. The description adds context that it is a preview before committing to a send, which aligns with annotations. No contradiction, but no additional rich behavioral details beyond what annotations cover.

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?

Description is four sentences, each providing essential information without redundancy. It is front-loaded with purpose, followed by parameter guidance, internal usage note, and advanced use case. No wasted words.

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 complexity (4 params, no output schema), description adequately covers purpose, parameter usage, and relationship to siblings. Lacks explicit mention of return format or error handling, but the raw tool nature and annotations provide sufficient context.

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%, baseline 3. Description adds value by providing concrete examples of resource_parameters shapes for different resource types and explaining that fields accept HTML, URL, or template IDs. The extra parameter is also clarified.

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?

Description clearly states it creates a PDF preview of a resource for review before sending, specifying resource types (postcard, letter, self-mailer). It distinguishes itself from sibling ‘lob_*_preview’ tools by noting it is a raw tool for advanced use cases.

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?

Description explains how to pass resource_parameters matching the create endpoint shape and suggests using preview tools normally. However, it does not explicitly state when not to use this tool or provide alternatives beyond the note.

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