Add a budget expense to a Wanderlog trip

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

No annotations exist, so the description carries the full behavioral burden. It does disclose the return value ('confirmation with the expense amount and description') and the place-existence precondition, which is genuinely useful. It says nothing about permissions, whether the expense can be edited afterwards, or side effects on the trip budget total beyond the linked/unlinked distinction.

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 paragraphs, front-loaded with purpose and mode selection before the usage example. The place-linking point is restated in both paragraph one and the closing prerequisite sentence, which is mild redundancy but functional as a constraint reminder.

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 7-parameter mutation tool with no annotations and no output schema, the description covers purpose, mode selection, a precondition, and the return value. The remaining gap is mutation semantics — reversibility and any permission requirements — which matters somewhat for a write operation but is partially mitigated by the existence of wanderlog_edit_expense and wanderlog_remove_expense siblings.

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%, so every parameter is already documented in the schema, giving a baseline of 3. The description reinforces the semantics of the 'place' parameter (linked vs standalone) but adds no new detail such as currency/category interactions or date defaulting beyond what the schema states.

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+resource ('Adds a budget expense to a Wanderlog trip') and the second sentence clarifies the two modes of the operation (linked vs standalone). It separates it from siblings like wanderlog_edit_expense and wanderlog_remove_expense implicitly through the verb, but never names an alternative explicitly.

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?

'Use this to give the trip a cost dimension — estimated meal costs, entrance fees, transport passes' provides concrete usage context and examples. It also states a real prerequisite ('If you link a place, it must already exist in the trip'). It does not, however, route the agent to a sibling for correcting or deleting an expense.

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