canvas_document_capabilities

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description does add useful substance beyond that — it discloses that reading limits are 'bounded' and that OCR/conversion support is stated 'explicitly' — which tells the agent the response carries constraint information. It stops short of saying whether limits are per-file or per-account, or what happens when a document exceeds them.

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?

It is certainly short, but the brevity comes at the cost of structure: it is an unpunctuated nominal fragment rather than a front-loaded statement of action. Very little is wasted, yet the single clause does not orient the agent before it reads further.

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?

An output schema exists, so the description need not explain return values, and there are no parameters to document. What remains missing is the routing information — when this introspection tool is warranted relative to canvas_capabilities and the file-reading siblings — which is the main thing an agent needs here.

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 tool takes zero parameters and schema coverage is 100%, so there is nothing for the description to disambiguate. Baseline 4 applies for a no-parameter tool.

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 is a noun-phrase fragment ('Supported formats, bounded reading limits, and explicit OCR/conversion availability') with no verb, so the agent must infer that the tool reports capability metadata rather than manipulating documents. It also does not distinguish itself from the sibling canvas_capabilities or canvas_confirmation_capabilities, which sound nearly identical in scope.

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 statement of when to call this tool, no prerequisite context, and no pointer to the closely named canvas_capabilities sibling as an alternative. The agent is left to guess whether this should be consulted before get_file, fetch_file_content, or canvas_read_file.

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