mark_item_purchased

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

No annotations are present, so the description must fully disclose behavior. It only states it marks as purchased, but does not mention error handling (e.g., if item already purchased, if list/item not found), side effects (e.g., irreversible), or required permissions. The mutation nature is clear, but details are lacking.

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?

The description is extremely concise with two sentences plus a clear Args list. The purpose is front-loaded in the first sentence. No unnecessary words.

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?

Given the tool's simplicity (mark item as purchased), the description is mostly adequate but lacks information about return values or success/error responses. Since an output schema exists, the agent could infer the return format, but the description does not mention what the tool returns. It is minimally complete.

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?

The description lists the parameters with brief definitions ('The numeric ID of...'), which adds slightly more than the schema's titles. Since schema coverage is 0%, the description does provide some semantic context, but it is minimal and essentially restates the schema for simple integer IDs.

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 uses a specific verb ('Mark') and resource ('item in a shopping list') with a clear outcome ('as purchased'). This clearly distinguishes it from sibling tools like add_item, delete_item, update_item_amount, etc.

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?

No guidance is provided on when to use this tool versus alternatives. For example, it does not mention that items must exist or that this is for toggling purchase status rather than updating other fields. The distinction from update_item_amount is implicit but not explicit.

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