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

The readOnlyHint annotation already signals safe read behavior; the description adds useful context by enumerating exactly what is returned: provider, plan type, limits, and upgrade_url. It also explains Plus plan details, which helps an agent interpret the response.

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 information-dense sentence that front-loads the core purpose before listing plan details. It is slightly verbose with pricing specifics, but each detail contributes to understanding the return value.

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 no output schema, the description carries the burden of explaining return values, and it does so thoroughly: identity, provider, plan, all limits, and upgrade URL. The tool is simple with no params, and the description fully equips an agent to invoke and interpret it.

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 and 100% schema coverage, so the baseline is 4. There is nothing for the description to add about parameter usage, and it does not invent or misrepresent any.

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 clearly states a specific action (return identity of current token holder) and resource (account + provider, subscription plan, plan limits). It is unambiguous and distinct from sibling tools like account_status by focusing on token identity and plan details.

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?

Usage is implied: call this when you need the current token's identity and plan limits. However, there is no explicit guidance about when to prefer this over siblings like account_status or get_status, and no exclusions are given.

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