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

Annotations already declare readOnly/idempotent/non-destructive, yet the description still adds real substance beyond them: it cannot mutate anything, a team-member key surfaces the OWNER rather than the member, and refusals from gated tools are described as real with no workaround. The instruction to read `_derived` before proposing Pro steps is concrete behavioral guidance not present in any structured field.

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 return payload and the 'call this first' directive, and every sentence carries distinct information (scope, key resolution, gating, no-write boundary). It is dense — the final sentence about refusal workarounds restates the gating point — but not padded.

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?

There is no output schema, so the description carries the burden of explaining returns and it does so explicitly (identity fields plus `_derived`). It also covers the two edge cases an agent would get wrong on its own: permission-gated steps and the team-member key resolving to the owner.

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?

Zero parameters, so the baseline of 4 applies. The description's only parameter-adjacent content is `_derived`, which is a response field rather than an input, but it is useful signal about what to inspect before acting.

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+resource ('The authenticated account') and enumerates exactly what it returns: name, email, role, plan, entitlements, notification settings. It explicitly bounds itself against siblings ('Identity and entitlements only. It reports no campaign or lead data'), so an agent can distinguish it from account_settings_update or analytics_account without opening a 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 a hard directive — 'Call this first in a new conversation' — with the reason (the plan gates Pro-only steps). It names the alternative for writes ('profile edits are account_settings_update') and explains the team-member-key case up front, including why the backend resolves it to the owner.

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