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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false. The description adds useful nuance by saying 'fully replace,' clarifying that existing content is overwritten. However, it does not mention permissions, side effects, or whether the operation creates a new document when the slug is absent.

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 tight sentence with zero waste. The core action and replacement semantics are front-loaded.

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 six parameters, required run and playbook identifiers, and no output schema, the definition is minimally viable but thin. An agent can invoke it using the schema, but the description does not explain return behavior, slug uniqueness, or what happens when replacing an existing document.

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 all six parameters are already documented in the input schema. The description adds no parameter-specific detail beyond the general notion of writing a canvas document, which is acceptable given the full schema coverage.

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 and resource: create or fully replace a canvas document. It is clear what the tool does, but it does not explicitly differentiate from sibling tools like read_canvas or list_canvas.

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?

There is no guidance on when to use this tool versus alternatives such as read_canvas, list_canvas, or update_persona. It also omits prerequisites like needing a valid playbook_id and run_id.

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