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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered structurally. The description adds genuinely new behavior beyond that: the receipt is removed from storage alongside the expense, and the action is irreversible — the cascade is the key detail an agent could not infer.

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 verb and scope, then the prerequisite, then the irreversibility warning. Slight redundancy between "permanently" and "cannot be undone" keeps it from a 5.

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 single-required-param mutation with no output schema and full annotation coverage, the description supplies the two things an agent most needs: the storage cascade and the irreversibility warning. A note on the return value or confirmation behavior is the only minor gap.

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%, so all three parameters, including the confirmation-only title and vendor fields, are already documented in the schema. The description reiterates that the ID is required and sourced from list_expenses but adds no new meaning; baseline 3 applies.

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 and resource ("Delete an expense permanently") and immediately discloses the scope of removal, distinguishing it from update_expense or list_expenses without needing 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?

Explicitly routes the agent to list_expenses when the ID is unknown, which is a real prerequisite for this tool. It stops short of stating when deletion is inappropriate (e.g., soft-close vs. delete), so it is clear context rather than full when/when-not guidance.

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