Get my unread message count

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds no further behavioral context, such as response format, latency, or any special conditions. It essentially restates the tool's purpose without enhancing what annotations already convey.

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, focused sentence that is appropriately sized for a tool with no parameters. It is front-loaded with the core information and contains no unnecessary words or filler.

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 simple, parameterless read operation, the description is largely complete. It explains the result (a count) and the scope (unread inbox messages). While it does not specify the exact return type (e.g., integer), the absence of an output schema and the trivial nature of the tool make this a minor omission. An agent can invoke this tool without ambiguity.

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?

With zero parameters, the schema is 100% covered (vacuously) and the baseline is 4 per the rubric. The description adds clarifying context by specifying that the count concerns 'unread inbox messages,' which is slightly more specific than the tool name alone. No parameter details are needed.

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 exactly what the tool returns: a count of unread inbox messages. It uses a specific resource (unread messages) and a clear action (get count). It is not a tautology and is distinct from sibling tools like canvas_get_conversation, which fetches a single message, or canvas_list_conversations, which retrieves multiple messages.

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 provides no guidance on when to use this tool versus alternatives. It does not mention that this is the quick way to get an unread count, nor does it contrast with other message-related tools. The agent is left to infer usage from the name, which is straightforward but lacks explicit routing.

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