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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the description's extra value is in disclosing the payload contents — permissions, plan, credit balance — which is exactly the right addition. It stops short of explaining how the 'selected' account is determined given zero parameters, or any freshness/rate-limit behavior.

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 sentences, no filler, with the positive capability stated first and the negative scope last. Every clause carries information the agent needs.

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 carries the burden of naming the returned fields, and it does so. The one remaining ambiguity is the zero-parameter 'selected' account — the agent is left to infer how the target account is chosen, which matters for a read whose result depends on it.

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 no parameter semantics to document and the baseline of 4 applies. The word 'selected' hints that account targeting happens out-of-band (likely via credentials), though the description does not confirm that.

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?

A specific verb ('Read') plus resource ('personal account or team') with the returned data enumerated: granted permissions, existing plan, subscription credit balance. It is clear what the tool does, but it never distinguishes itself from the sibling get_team — an agent could plausibly pick either for team-related reads.

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?

'Does not purchase credits or change billing' is an explicit when-not boundary that steers the agent away from expecting mutation. However, no alternative tool is named for billing actions, and there is no stated precondition or context for when to reach for this versus get_team.

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