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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: it explains that 'paused' means chat, replies, campaign pushes and AI replies all stop until a plan is chosen, and that nothing is deleted — precisely the kind of consequence an agent needs to interpret the result.

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 return payload is front-loaded in the first sentence and the paused-state consequence follows. The sentence is long and parenthetical-heavy (the state breakdown and dashboard path could be tighter), but 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?

With no output schema, the description carries the return-value burden and does so by enumerating the fields (name, plan, state with daysLeft/trialEndsAt, plans, planUrl, role, dashboard link). A minimal read-only tool is adequately covered; only the exact shape of the plans list is left vague.

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; the baseline for a zero-parameter schema applies. No misleading parameter-like claims are made.

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 a specific resource (the Hailbell account bound to the current key) and enumerates exactly what is returned: name, plan, billing state, plans on offer, planUrl, dashboard link, and the caller's role. That is enough to separate it from siblings like get_user, get_setup, and get_context, though it never names those siblings explicitly.

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: an agent can infer this is the tool for checking plan/billing status and the connected user's role. There is no explicit when-to-use statement and no routing away from get_user or get_setup, which likely overlap on identity/setup information.

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