invoices_update_invoice_last_visited_at

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

The description adds no behavioral information beyond what the tool name already implies. Annotations already indicate readOnlyHint=false (a write operation) and destructiveHint=false (non-destructive), but the description doesn't explain side effects like updating analytics, triggering notifications, or the idempotent nature (which annotation says is false). Since annotations are present, the description could add context about why this update matters, but it doesn't. It's essentially a verbal restatement of the tool name.

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 a single short sentence with no filler or redundancy. It gets to the point immediately. It's concise, though it could arguably be more informative without being verbose. For a tool with one parameter, this level of brevity is acceptable, but it borders on being overly terse.

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 low complexity (one parameter, no output schema), the description is still incomplete. It doesn't explain the purpose of updating 'last visited at' (e.g., for tracking user engagement) or any effects of calling it. An agent would have to guess why this specific field matters and what the response looks like. With no output schema, the description should provide more context about expected behavior, but it doesn't.

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 schema provides full description coverage (100%) for the single parameter 'invoiceId', so the description doesn't need to explain it. The schema's 'description' field already says 'Invoice Id', which is sufficient. The description itself adds no extra meaning about the parameter, so a baseline of 3 is appropriate given the high schema coverage.

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 states a clear verb ('Update'), a specific resource ('invoice'), and a specific field ('last visited at'). It distinguishes this from general invoice updates by naming the exact field being changed, which helps an agent understand the narrow purpose. However, it doesn't explicitly differentiate from the sibling invoices_update_invoice_last_visited_at (which is identical) or other invoice update tools like invoices_update_invoice, so it's clear but not fully distinctive.

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 such as invoices_update_invoice or the generic update tools. There is no mention of triggering conditions, prerequisites, or scenarios where this should be preferred. The description only says 'Update invoice last visited at' without explaining its typical use case (e.g., marking that a user has viewed an invoice), leaving the agent to infer when to invoke it.

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