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

With no annotations provided, the description carries the full burden and does so well: it declares the Pro-subscription prerequisite, the ACL check (support_contact), that no quota is spent, the exact return shape ({ok:true}), and explicitly enumerates what it does NOT touch (billing, storage, inboxes). That is unusually complete side-effect disclosure.

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 the action and the qualifying condition, then each subsequent sentence carries distinct information (delivery, return value, prerequisites, non-effects) with no filler or repetition.

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 two-parameter tool with no output schema, the description supplies everything an agent needs: preconditions, the return value, and the boundaries of its side effects. Nothing material is missing.

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 both parameters are already documented with required flags and purpose, so the baseline is 3. The description adds only that subject/message are 'sent to the Tillpad team', which is marginal value beyond the 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+resource ('Email Tillpad support') and scope ('from a Pro account'), with no sibling in the list doing anything similar. An agent can immediately tell this is the support-contact channel rather than any inbox/billing/document tool.

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?

Gives clear qualifying context — must be an active Pro account, and replies are routed to the account email — so the agent knows when this tool is applicable. It does not name an alternative path for non-Pro accounts or state explicit exclusions, which keeps it short of a 5.

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