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

The description says the tool deletes all mail irreversibly ('There is no refund'), but the annotations declare destructiveHint=false. This directly contradicts the structured safety profile, so the description cannot be trusted on behavior without resolving the inconsistency.

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?

Three short sentences with the core action front-loaded. The warning and cost note are compact, though the semicolon construction in 'Free; needs the inbox id and secret.' is slightly awkward.

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 simple delete tool with complete parameter documentation and no output schema, the description covers the destructive effect and required inputs. However, it omits usage alternatives, permission requirements, and fails to reconcile the behavioral contradiction with annotations.

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 coverage is 100%, with both parameters already documented. The description only restates that the inbox id and secret are needed, adding no syntactic or semantic detail beyond the 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?

The description names a specific verb and resource: 'Delete an inbox and all its mail now.' This is clear and distinct from siblings like create_inbox and extend_inbox, though it does not explicitly differentiate itself from any alternative.

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 on when to use this tool versus alternatives, nor any exclusions or prerequisites. The 'no refund' warning describes an effect, not usage context.

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