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

Annotations already flag destructiveHint=true and readOnlyHint=false; the description goes further by naming what destruction means (loss of access to mailbox content) and by warning 'read needed messages before deleting'. It also discloses that there is 'No additional charge or new payment' and that it does not read messages - real behavioral context rather than a restatement of the annotation.

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?

Four short sentences, front-loaded with the destructive action and followed by cost, prerequisites and a warning. Every sentence carries information, though the telegraphic style ('No additional charge or new payment') is marginally redundant phrasing.

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 an output schema present and annotations covering the safety profile, the description supplies what an agent still needs: prerequisites, cost implications, and the data-loss warning. Nothing critical is missing for a 3-parameter destructive 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 33%, so the schema carries most of the burden (patterns for inbox_id and capability; the access_token fallback case). The description adds genuine value by stating all three values come from create_email_inbox, establishing provenance, but it adds no format or constraint detail beyond 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?

The description opens with a specific verb and resource ('Delete your existing inbox') and immediately adds the secondary effect ('revoke access to its mailbox content'), which distinguishes it from sibling tools like create_email_inbox, list_email_messages and get_email_code. An agent knows exactly what this does without inspecting the 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?

It gives a clear usage context ('Useful after testing is complete') and states the prerequisite chain ('Takes inbox_id, capability and access_token from create_email_inbox'), which tells the agent it must call the create sibling first. It lacks an explicit when-not-to-use clause, so it falls short of a 5.

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