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

Annotations only cover the generic safety profile (write, open-world, non-idempotent, non-destructive). The description adds materially: nothing is charged at this step, the user reviews and pays on GiftsToPrint's own checkout, and validation errors are returned all-at-once so they can be fixed in a single pass. These are non-obvious behavioral traits an agent could not infer from structured fields.

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?

Front-loads purpose and return value, then prerequisites, then error behavior. Sentences are dense but each carries distinct information; no obvious filler. Slightly long for the content, keeping it below a 5.

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 supplies the key return value (checkout_url) and the follow-up action (open it for the user). For a write tool with annotations covering safety, the mixture of preconditions, consent requirement, non-charging behavior, and error semantics makes it complete enough to call correctly.

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 88%, so the schema already documents nearly every parameter, including the enumeration for turnaround and the semantics of personalisation. The description reinforces confirm_digital_file and the photo_url step but adds little syntax or format detail beyond what the schema provides, so the baseline 3 is appropriate.

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 ('Validate every detail and create a Shopify checkout for one personalised poster') and names the artifact returned ('checkout_url'). It is clearly distinguishable from siblings find_posters, get_poster_form, and upload_photo, which are inputs to this action rather than alternatives.

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?

Gives explicit preconditions for invocation: read details back to the user, verify photo_url is the right photo, and obtain consent by setting confirm_digital_file to true. It also ties inputs to their sibling tools (handle from find_posters, photo_url from upload_photo). It does not state when NOT to use the tool, so it falls short of a full 5.

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