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

Beyond the readOnlyHint annotation, the description adds important behavioral guardrails: 'Don't invent names or dates' and 'Ask the user for anything you don't already know.' It also explicitly scopes exactly what the tool collects, giving the agent a clear model of the tool's behavior and constraints.

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 compact: three sentences, each earning its place. The first defines output scope, the second gives user-interaction guidance, and the third provides next-step sequencing. No redundant or vague content.

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?

With no output schema, the description sufficiently explains what the tool returns (the list of fields to collect), how to act on that output ('Ask the user...'), and the surrounding workflow. The only missing context, the source of the handle, is already covered by the schema description.

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 both handle and buyer_country are already well documented in the input schema. The tool description does not add parameter-specific detail, such as mentioning buyer_country or elaborating on handle, but the high baseline 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?

The description starts with a specific verb and resource: 'List exactly what to collect from the user for one poster: names, dates, optional message, and the photo, plus the turnaround options and prices.' It clearly differentiates the tool from siblings by defining its role as data collection, and the workflow note ('Next step: upload_photo, then create_poster_checkout') further distinguishes it from upload and checkout tools.

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 provides clear workflow context: 'Ask the user for anything you don't already know' and 'Next step: upload_photo, then create_poster_checkout.' It does not explicitly mention when not to use the tool or compare against find_posters, but the handle parameter is documented as coming from find_posters in the schema.

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