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

Annotations already indicate this is a mutating operation (readOnlyHint=false, destructiveHint=false), so the description doesn't need to restate that. The description adds useful context about page selection and the direct-call behavior, but it doesn't disclose what happens if the template ID is invalid, whether the design is created in a specific folder, or what the response contains. With annotations covering the basic safety profile, a 3 is appropriate.

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 and front-loaded: the core action is stated first, followed by the optional behavior, then the routing guidance. Every sentence earns its place, and the guidance is actionable without being verbose.

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 creation tool with no output schema, the description covers the main decision points: when to call directly, when to search, and when to use autofill. It doesn't describe the return value or error cases, but the routing guidance and parameter semantics are strong enough that an agent can invoke the tool correctly in most scenarios.

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 the schema already documents all three parameters. The description adds context for `page_numbers` (optional, 1-based, omit for all pages) and `brand_template_id` (direct-call behavior), but it doesn't add meaning beyond what the schema already provides. Baseline 3 is correct.

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 states a specific verb ('Create') and resource ('a new Canva design from a brand template'), and explicitly distinguishes itself from the sibling `search-brand-templates` and `autofill-design`. It also clarifies the optional page selection behavior, making the tool's purpose unambiguous.

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 explicit when-to-use guidance: call directly when a brand template ID is already known, do NOT call `search-brand-templates` first, and use `autofill-design` instead when custom data needs to be filled. This is strong routing guidance that leaves little to inference.

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