Insert Image

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

With no annotations, the description carries full responsibility. It discloses the key behavioral trait that the API lacks an endpoint, making any call to this tool fail. This is critical and goes beyond the schema. However, it does not specify the exact error behavior or response, so it is not maximally transparent.

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 a single sentence that immediately states the essential warning. It is concise, front-loaded, and contains no unnecessary words, making it highly efficient for the agent to parse.

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 tool explicitly declared non-implementable, the description covers the most important fact: it cannot be used. However, it omits potential alternative tools and does not explain why the tool exists, which leaves a small gap. Given the simplicity of the schema and lack of output schema, the description is mostly complete for preventing misuse.

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?

The description provides no information about the four parameters (presentationId, slideId, assetId, placementHint), and schema coverage is 0%. Since the tool is non-functional, parameters are irrelevant, but the description still fails to compensate for the lack of schema descriptions, leaving the agent with no semantic understanding of the parameters.

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 clearly conveys the intended operation (insert an image into an existing design's slide) and immediately states it cannot be performed because the Canva Connect API lacks an endpoint. This makes it unambiguous that the tool is non-functional, but it does not explicitly compare with sibling tools beyond the negative statement, so it stops short of a perfect score.

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 gives a clear when-not-to-use directive ('Not implementable'), which is explicit. However, it provides no alternatives or guidance on how to achieve the desired outcome through a different tool, such as update_slide_content. Thus the usage guidance is present but incomplete.

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