create_mailbox

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

No annotations are present, so the description carries the full disclosure burden. It does disclose the mutation nature ('Create'), the ephemeral lifecycle ('temporary'), and the return value, but it omits failure modes (e.g., unavailable username/domain), idempotency, and any side effects or provider resource consumption that would help an agent anticipate outcomes.

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 with zero filler; the primary action is front-loaded and the second sentence about the return value earns its place. Nothing could be removed without losing information.

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?

The input schema is fully self-documenting and all parameters are optional, but annotations and output schema are absent, leaving the description as the sole behavior and return disclosure. It covers the basics but lacks output shape detail, failure behavior, and sibling routing, which are meaningful gaps for a resource-creating tool.

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?

Schema description coverage is 100%: domain, provider, and username each have descriptions including defaults and behavior when omitted. The tool description adds no parameter-level meaning, so the baseline of 3 applies per the high-coverage rule.

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 verb ('Create') and resource ('temporary email mailbox') and states the return value ('email address and account details'), making the core purpose clear. It does not explicitly differentiate itself from siblings such as auto_register or list_mailboxes, so it misses the sibling-distinguishing bar for a 5.

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?

There is no guidance about when to use this tool versus alternatives. The description never mentions conditions like 'use this when you need a fresh disposable address' and names no sibling or exclusion, leaving the agent to infer selection from the tool name and the word 'temporary' alone.

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