update_purchase

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

With no annotations provided, the description carries the full behavioral burden and largely fails it. It does not say whether the update is partial (merge) or full replacement, whether fields omitted from the 'purchase' object are preserved, whether status can be set to VOIDED here versus via a void tool, or what permissions are required.

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?

One short sentence with no wasted words and the action front-loaded, but the brevity reflects under-specification rather than disciplined economy. It fits on one line but conveys almost nothing an agent could not guess from the name.

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 mutation tool with no annotations, no output schema, and a nested required object with 50% schema coverage, this description is too thin. An agent cannot know the update semantics, side effects on status, or error behavior from it.

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 only 50%; the nested 'purchase' object's properties (memo, status, referenceNumber) are documented in the schema, but the object itself and the semantics of a partial update are not. The description adds no parameter-level meaning beyond the schema, leaving the merge/replace question unresolved.

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 ('Update an existing purchase'), and the parenthetical '(expense)' clarifies KikoBooks' terminology. However, it gives no field-level or scope detail and does nothing to distinguish it from the many sibling update_* tools (update_bill, update_deposit, update_invoice).

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 indication of when to use this versus update_bill, update_deposit, or delete_purchase, nor any prerequisite such as needing a purchase_id obtained from search_purchases or get_purchase. The agent must infer the workflow entirely.

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