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

Annotations already declare a non-read-only, non-destructive write, and the description adds value beyond them by disclosing the return payload (id, status, total) and the side effect on the profile's next scheduled date. It does not clarify whether this advances/skips the schedule or creates a duplicate invoice, which is the main behavioral ambiguity left.

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 sentences, front-loaded with the action, then the related sibling, then the return value. No filler or restatement of the title.

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?

With no output schema, the description usefully documents the return shape and the scheduled-date side effect, and annotations cover the safety profile. The one gap is guidance on sourcing the profile_id, which matters for a single-required-param tool with 0% schema coverage.

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 coverage is 0% and the single profile_id parameter has no description, so the description carries the burden; it implies the parameter identifies an existing recurring profile but never states the expected type, nor how to obtain a valid ID (e.g. via list_recurring). Partial compensation only.

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?

States a precise verb+resource ('Generate an invoice now from an existing recurring profile') and explicitly distinguishes it from the sibling that creates profiles ('Create profiles with create_recurring'). An agent can tell this apart from create_recurring, update_recurring and list_recurring without opening any schema.

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?

Explains the precondition (an existing recurring profile) and points to create_recurring as the alternative for profile creation, plus 'now' signals immediate generation rather than scheduled. It never says what to do if no profile exists or how this differs from calling create_invoice directly, so no explicit when-not guidance.

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