mark_as_sent_invoice

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

The description adds no behavioral detail beyond what annotations already convey. It does not disclose whether this operation triggers side effects like email dispatch, modifies timestamps, or requires specific permissions. Given the annotations indicate a non-read-only, non-idempotent operation, the agent has to guess the exact semantics of 'mark as sent'.

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—a single phrase with no filler. It is front-loaded and easy to parse, but it is so brief that it risks being under-informative, which prevents a perfect score.

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?

Despite the tool's simple interface (one parameter, no output schema), the surrounding context is complex with multiple invoice-related tools. The description does not clarify the difference between 'marking' and 'sending', nor the potential downstream effects, making it insufficient for confident invocation in all scenarios.

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 input schema has 100% coverage for the only parameter, 'invoice_id', with a straightforward description. The tool description adds no additional parameter-level meaning, so the baseline score of 3 applies because the schema already carries the necessary information.

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 'Mark invoice as sent' uses a specific verb ('mark') and resource ('invoice') with the resulting state ('as sent'), making the core purpose clear. However, it does not differentiate this from sibling tools like 'send_invoice', 'issue_invoice', or 'mark_as_sent_invoice_reminder', which could have similar state-change effects on invoices.

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 guidance on when to use this tool versus alternatives such as 'send_invoice' or 'issue_invoice'. The description does not provide any context about the expected workflow or prerequisites, leaving the selection decision entirely to the model.

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