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

With no annotations, the description carries the full burden and does well: it discloses the return payload (public link, per-guest link, preview image, rendered PNG per guest with a &format=jpeg toggle) and warns that the editKey is secret and required for later edit/delete. It stops short of stating auth requirements, whether publishing makes the link publicly reachable, or throughput limits.

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?

Two tight sentences, purpose front-loaded, then output contract, then the two formatting rules an agent must apply. Dense but every clause earns its place; no padding or repetition of the schema.

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 10-parameter tool with deeply nested blocks/envelope schemas and no output schema, the description covers the output shape and key formatting rules well. It is slightly thin on auth, link permanence, and the guest-capacity implications, but nothing critical to correct invocation 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 high (90%), so the baseline is 3, but the description adds genuinely schema-absent meaning: the local date formats ("2026-11-14" whole-day vs "2026-11-14T18:00") and the {name} templating convention for per-guest addressing. This compensates for the date-block format gap the schema leaves open.

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 ("Create and publish an invitation or letter") that is immediately distinguishable from the create/update/get/delete sibling set. It does not explicitly name the sibling it complements (update_letter), but the action is unambiguous.

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 explicit "use this when..." or "for modification use update_letter" guidance. The mention that the editKey should be kept "to edit or delete later" implicitly signals the follow-up workflow but leaves the when-to-use decision to inference.

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