subscription_status

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

With no annotations, the description carries the full behavioral burden, and it does convey the two return facts (status and renewal date) plus per-user scoping. It is silent on what happens when the user has no active subscription (empty result vs. error) and on auth requirements, which matters for an account-state lookup.

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 front-loaded sentence that states the resource and the returned fields, with no filler. There is nothing an agent would want removed.

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 trivial zero-parameter read tool with no output schema, naming the two returned fields (status and renewal date) is close to sufficient. The main residual gap is the inactive/no-subscription case, which an agent might hit and cannot predict from this text.

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 no parameters, so there is nothing for the description to disambiguate beyond confirming the call is implicitly scoped to the current user. That confirmation is present, so the baseline for a zero-parameter tool applies cleanly.

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 pairs a specific verb ("Retrieve") with a specific resource ("active subscription status and renewal date"), so the agent knows exactly what it gets back. It does not explicitly contrast itself with the neighbouring remaining_credits tool, which is the closest sibling and would otherwise be a natural point of confusion.

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 only implied: the agent can infer it should call this when it needs billing/subscription state, and the zero-parameter schema means there is no wrong way to invoke it. However, there is no stated when-not condition and no pointer to remaining_credits when the caller actually wants credit balance.

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