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 known. The description still adds substantive behavior not in the annotations: attached expenses are cascade-deleted because an expense cannot outlive its journey, and it restates permanence plus the confirmation requirement. That is real added value beyond structured data.

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, front-loaded with the action and its cascade consequence, ending on the confirmation constraint. Minor redundancy: permanence is asserted twice ("Permanently delete" and "This permanently deletes the record"), which costs a few words but does not bury the important 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?

For a one-parameter destructive tool with no output schema and full annotation coverage, this covers everything an agent needs: what is removed, that related expenses go with it, that it cannot be undone, and that confirmation must precede the call.

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?

There is a single required parameter with 100% schema description coverage ("ID of the journey to delete"), so the schema already does the work. The description only echoes "by id" without adding format, source, or lookup guidance — the baseline 3 fits.

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 ("Permanently delete a journey by id"), naming the lookup key. Siblings like delete_expense and delete_stay operate on different resources, so the target of this deletion is unambiguous without opening 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 supplies a clear gating condition — call only after explicit user confirmation of deletion — which is exactly the kind of usage constraint an agent needs before an irreversible action. It stops short of pointing at alternatives (e.g. update_journey if the user only wants changes), so it is not a full when/when-not map.

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