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

The annotations already declare the read-only, idempotent, non-destructive, closed-world profile, so the bar is lower. The description still adds genuinely useful behavior that the annotations do not cover: the reporting window is the UTC day, 'limit' and 'remaining' are null unless an operator cap applies, and the call is self-excluding from usage counting.

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?

Three short sentences, each with a distinct job: what is returned, how to interpret the null values, and the self-exclusion caveat. The scoping is front-loaded and there is no 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 zero-argument read this is nearly complete, and the null semantics of 'limit' and 'remaining' partly compensate for the missing output schema. However, the full return shape is left implicit, so an agent does not know everything it will receive back.

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, so the baseline is 4 and no schema compensation is needed. The description does not add parameter meaning, but none is missing.

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 uses a specific verb and resource ('Return this workspace's MCP usage') and scopes it to 'the current UTC day', so the agent knows exactly what the tool produces. Differentiation from the sibling tools is unnecessary here because search_papers and get_paper_details are clearly unrelated resources.

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 implies the usage-checking context and rules out quota concerns, but it never says explicitly when to call it (for example, after a rate-limit error or before a large batch) and names no alternatives. Usage is inferable rather than stated.

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