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

With no annotations, the description carries the full behavioral burden. It does not state that this is a read-only introspection, whether it requires authentication, whether 24h spend is live or cached, or whether the call has side effects or rate limits.

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?

A single eight-word sentence with zero waste and the key subject front-loaded. It is appropriately sized for a zero-argument tool, though it reads as a bare list rather than structured guidance.

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 and no annotations, the description is the only place return values could be explained, and it does list the three returned categories. However it omits units, currency, and the shape/semantics of 'scopes' and 'spend limits', leaving the agent to guess at the response structure.

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 and the schema is fully self-describing, so the baseline is 4. There is nothing parameter-related the description could add.

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 exact resource (the current key) and enumerates the three things it returns: scopes, spend limits, and 24h spend. No sibling tool reports key identity or limits, so it is effectively distinguishable even though it uses a noun phrase rather than a verb.

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?

There is no when-to-use guidance: nothing tells the agent to call this before a spend operation, nor what alternative exists for account-level or order-level queries. The 24h-spend mention hints at a pre-spend check but never states it.

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