canvas

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

With no annotations, the description carries full responsibility for disclosing behavioral traits. It only lists action names without explaining side effects, safety (e.g., eval executes JavaScript), or response behavior. This is a significant gap for a multi-action tool.

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, front-loaded with the resource and action list. It is succinct without waste, though it sacrifices explanatory value for brevity.

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?

This is a complex tool with 8 parameters, 7 actions, and no output schema. The description is severely incomplete—it doesn't explain action behaviors, parameter combinations, or return values, making it inadequate for an agent to use 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 100%, with each parameter having a description, so the baseline is 3. The description adds no parameter meaning beyond what the schema provides, merely repeating the action list already present in the schema's action property.

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 identifies the resource (Canvas visual workspace) and provides a list of actions, but 'Control' is generic and doesn't clarify what the workspace is or how it relates to sibling tools like browser. It lists actions but gives no detail on what each does, making it hard to distinguish from 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?

No guidance on when to use this tool versus browser, web_fetch, or others. There are no exclusions, prerequisites, or context signals indicating the intended use case, leaving the agent to infer usage.

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