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

Goes well beyond the annotations: it discloses that the change is immediately visible on a published sign-up, that no one is notified, that it proceeds without confirmation, that a below-capacity quantity is refused, and that a Cotlet API key with app access is required. These side-effect and auth details are exactly what an agent needs before a mutation.

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?

Front-loaded with verb and resource, but the quantity constraint is stated twice ('cannot go below the people already signed up' and 'A quantity lower than the people already signed up is refused'), which is redundant and wastes space.

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 output schema, it covers side effects, the refusal condition, notification behavior, and auth requirements. It briefly notes the return ('returns the slot as it is now'), which compensates for the missing output schema, though it could say more about the response shape.

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 100% and the schema already enumerates the allowed fields ('Any of title, quantity, location, help_comment'), so the description's field list largely repeats structured data. The quantity-floor rule adds some semantic value but does not exceed the baseline for a fully-documented schema.

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 specific verb and resource ('Change a slot's title, quantity, location or help comment') and names exactly which fields are mutable. This clearly differentiates it from siblings like add_slots, publish_signup, and get_signup without needing to open the 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?

The description conveys context (behavior on published sign-ups, quantity floor) but never names an alternative tool or states when to prefer this over add_slots/remove_participant. Usage is implied rather than routed.

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