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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered. The description adds genuinely useful behavior context by enumerating exactly which account data is exposed (plan, trial end date, flow counts, folder limits, mic time), which is the only place this is documented since no output schema exists.

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?

One front-loaded sentence with no filler; the enumeration is dense but every item earns its place because there is no output schema to carry the return-field contract.

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-parameter read with no output schema, the description fully discharges the return-value burden by naming each field. Minor gaps remain (no note on null/empty values, units, or free-plan behavior), but nothing required to call it correctly is missing.

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 the baseline is 4 by rule. The description correctly implies an implicit session-scoped target ('signed-in user') rather than requiring any identifier, matching the empty schema.

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 clear verb ('Return') and a precisely scoped resource ('the signed-in user's current plan...'). The 'signed-in user's' framing implicitly distinguishes it from sibling org-level tools like get_organization and get_org_usage, though it never names those alternatives 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?

The description says what is returned but never states when to reach for this tool versus the many adjacent read tools (get_organization, get_org_usage, get_insights, get_checkin_status). No prerequisites or exclusions are given; usage must be inferred entirely from the field list.

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