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

Annotations declare readOnlyHint=false and destructiveHint=false, so it is known to be a mutating but non-destructive operation. The description adds the transactional nature ('draft transaction', 'same session') and what it returns (transaction_id and editable element data). It does not mention the need to later commit or cancel, but the transaction concept is adequately disclosed.

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 three sentences totaling about 60 words, with the core purpose front-loaded in the first sentence. Every sentence contributes: purpose, usage scenarios, and return value. No fluff or redundant phrasing.

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 there is no output schema, the description covers what is returned (transaction_id and editable data). It does not spell out the transaction lifecycle (commit/cancel) or error conditions, but the sibling tools make the next steps predictable, and the description is sufficient for an agent to initiate the intended workflow.

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% for both parameters (design_id and user_intent), and each has a clear description in the schema. The tool description does not add new parameter-specific guidance beyond reiterating that it returns element data, which is output-related. Since the schema already documents parameters, a 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?

The description opens with a specific verb ('Prepare') and resource ('an existing Canva design'), then states the outcome ('opening a draft transaction'). It enumerates exact use cases (text, media, titles, formatting, autofill labels) and clarifies it is for preparing changes or inspecting elements, distinguishing it from read-only tools like get-design-content and from the commit/cancel siblings.

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 explicitly says 'Use to prepare changes...' and 'or inspect the editable text and media elements before changing them,' which gives clear when-to-use context. It does not explicitly name alternatives or exclusions, but the phrasing implies this is the prerequisite step before modification, and the sibling list makes the transaction flow obvious.

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