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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces and expands on this by stating it is READ-ONLY, cannot change the plan or start a purchase, and that plan/billing changes are done by the user at usemycontext.ai. It adds meaningful behavioral context about side-effect safety beyond the structured annotations.

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 front-loaded with the core purpose and use cases, and it provides useful exclusions and safety context. However, it is slightly redundant, repeating the read-only message multiple times ('This is READ-ONLY', 'Read-only; nothing is written'), which adds unnecessary length.

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 zero parameters and an output schema present, the description covers everything an agent needs: what the tool does, when to use it, what it excludes, and its side-effect profile. The inclusion of the user-facing management URL adds practical context for follow-up actions.

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 has zero parameters, so there are no parameter semantics for the description to clarify. Since no parameter documentation is needed, the baseline of 4 applies; the description appropriately focuses on the tool's scope rather than parameters.

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 ('Report') and names the exact resource: the user's current plan and usage, including tier, projects, storage, subscription status, and plan management location. It also distinguishes itself from siblings by explicitly excluding files, facts, and profile content, making its scope unmistakable.

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 clearly states when to use the tool: when the user asks about their plan, usage against limits, or proximity to a limit. It also gives exclusions ('no files, facts, or profile content'), though it does not name alternative sibling tools explicitly, so it stops short of a full when-not/alternative guide.

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