Pay: subscriptions check access

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so 'Read-only' is largely a restatement. However, the description adds genuinely useful behavior beyond them: it clarifies that the check runs as the calling user and specifies the return payload (access boolean plus id, name and status), which matters since there is no output schema.

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?

Front-loaded with the core action and scope, and the routing hint is short and useful. The second sentence largely re-states the first ('Check whether the current user...' / 'Checks whether the signed-in user...'), which is minor redundancy rather than wasted space.

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 correctly compensates by describing the returned fields and the boolean result. Scope, required input, optional status filter, and the sibling alternative are all covered; the only meaningful omission is what a false/negative access result implies for follow-up actions.

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?

Schema description coverage is 100%, so both parameters are already documented. The description adds only a light gloss ('by name', 'optionally requiring a status'), which is roughly what the schema's 'Require a specific status (optional)' already conveys; baseline 3 is appropriate.

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?

States a specific verb (check access), resource (subscription), and the exact scope (the signed-in/current user) in the first sentence. It is clearly distinguishable from siblings like pay_subscriptions_get, pay_subscriptions_by_user, and pay_entitlement without opening any schema.

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?

Gives an explicit routing rule: 'For another user use `pay_subscriptions_by_user`', which is the main selection decision for this tool. It does not address other plausible alternatives (e.g. pay_subscriptions_get for details, pay_entitlement for entitlements), so it stops short of full coverage.

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