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

Annotations already declare readOnly, idempotent, non-destructive, so the description isn't needed for safety. It does add two pieces of information the annotations lack: the required 'billing:read' scope and the fact that the call is free, both of which affect whether an agent should attempt it.

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?

Two very short sentences, with the core payload (what is returned) front-loaded before the auth prerequisite. Nothing is repeated from the schema or annotations, and no sentence is 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 zero-param read tool the description covers prerequisites, but with no output schema in place the description is the only place to learn what actually comes back, and it only gestures at three fields (plan, status, credit allocation) without shape. Adequate but leaves a real gap for an agent planning to consume the result.

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 there is nothing for the description to disambiguate; baseline for an empty schema is 4. No parameter-level detail is missing because none exists.

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 (subscription plan, status, credit allocation) but uses no verb, leaving the read action implied by the name alone. It also overlaps with sibling tools like autoshort_get_credit_balance and autoshort_get_limits without distinguishing what makes this one different.

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 explicit when-to-use guidance and no mention of the alternatives (get_credit_balance, get_limits, get_usage_stats) that an agent would need to choose between. 'Free' hints at cost but is not stated in terms an agent can reason about without inference.

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