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

The annotations already declare non-read-only, open-world, idempotent, non-destructive. The description adds genuinely non-obvious behavior: a double opt-in flow where GCS emails a confirmation link, registration only completes on click, and the GCS team then follows up. It does not address duplicate submissions or what happens on a second call despite idempotentHint=true.

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 and followed by prerequisites and the post-submit flow. The opening 'Fill in Register for GCS for your user' is slightly awkward phrasing but no sentence is wasted.

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 14-parameter, open-world mutation tool the description covers the essentials: prerequisites, where enum values come from, and what happens after submission. Missing only edge-case behavior (re-submission, duplicates, response shape), which is minor given strong annotations and a fully documented schema.

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%, so the baseline is 3. The description restates a few schema facts (consent: true, the role list) and adds one useful pointer — non-enumerated values like goals and events come from get_registration_form — but adds little 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 action and resource (register a user for GCS) and enumerates the registrant types it serves (brands, investors, judges/experts, distributors, analysts, associations), which implicitly separates it from register_as_media. It never names register_as_media, though, so the closest sibling is left to inference.

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 context: use it to register a person, field values come from get_registration_form, and consent must be true. It stops short of explicit exclusions — nothing says when to pick register_as_media or subscribe_to_newsletter instead.

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