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

All annotation hints are false, so the description carries the burden of behavioral disclosure. It discloses an authentication requirement (sp_ API key) and characterizes the operation as 'Show', implying a read-only, non-destructive access. It does not explicitly state 'does not modify state', but given the tool name and description, this is sufficiently clear for an agent. No contradiction with 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 a single, focused sentence with no wasted words. The core purpose is front-loaded, followed by the auth requirement and the routing to an alternative, all in compact, scannable structure.

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?

This is a low-complexity, zero-parameter tool with an output schema present. The description covers the tool's purpose, authentication requirement, and the alternative for anonymous callers. Nothing needed for correct invocation is missing.

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 input schema has zero parameters and schema coverage is 100%, so there are no parameter semantics to document. The baseline of 4 applies because the description adds no unnecessary parameter commentary and there is nothing 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 names the resource ('the authenticated account') and a specific verb ('Show'), and enumerates the exact fields returned (plan, subscription status, usage). It also differentiates this tool from the sibling get_limits by explicitly stating the account-specific scope, leaving no ambiguity about what the tool does.

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 a precondition ('requires an sp_ API key') and explicitly routes anonymous callers to the alternative tool get_limits. This is direct when-to-use versus when-not-to-use guidance, with the named sibling alternative.

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