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

Annotations cover the safety profile (non-read-only, non-idempotent, non-destructive), and the description adds genuinely useful context beyond them: it requires an account token, it always targets the account email address rather than an arbitrary recipient, and it does not incur a charge. It stops short of disclosing failure behavior (e.g. no receipt on file) or any rate limit on repeated sends.

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 short sentences, zero padding, and the auth prerequisite is front-loaded before the action so an agent sees the constraint first. Every clause carries distinct information (auth, action, target, cost).

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, no-output-schema action with annotations carrying the safety profile, the description covers auth requirement, exact effect, fixed recipient, and cost. Only edge-case behavior (what happens when no recent receipt exists, repeat-send throttling) is unaddressed.

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 high. The description still adds value by making explicit that the recipient is fixed to the account email address, so an agent knows there is nothing to supply and no targeting option exists.

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 ("Emails ... again") plus the exact resource ("the most recent receipt") and the destination ("the account email address"). It implicitly distinguishes itself from the neighboring resend_owner_verification tool by naming 'receipt' rather than a verification message.

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 'use when the account holder needs another copy of the latest receipt' — but there is no explicit when-to-use, no exclusions, and no named alternative. The 'Does not charge' clause helps rule out billing intent but is not routing guidance.

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