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

Annotations already flag destructiveHint=true and readOnlyHint=false, and the description adds real value on top: the pure dry-run behavior when confirm=false, the fact that a code is submitted on confirm=true, and where the verification resource must come from. It does not state reversibility or what happens after a successful submission.

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 tight sentences with no filler; the core action leads, followed by parameter provenance and then the safety rule. Dense but every sentence earns its place.

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?

An output schema exists, so return values need not be described. For a 3-param destructive mutation with annotations, the description covers the action, required provenance, the PIN source, and the confirm gate; only post-success behavior and prerequisite tooling are omitted.

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 description coverage is 0%, so the description must carry the burden and largely does: it defines verification as the resource name from gbp_verification_options history, describes pin as the code delivered by postcard/SMS/email, and explains confirm's dry-run vs submit semantics. Pin format/length details remain unstated.

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 ('Completes a PENDING verification by entering the PIN/code Google sent') and names the exact provenance of the required resource, which distinguishes it from the sibling gbp_start_verification and gbp_verification_options.

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 'PENDING verification' precondition and the confirm=false preview vs confirm=true submit rule give clear when-to-use guidance. It does not explicitly route the agent to gbp_start_verification or gbp_verification_options as the prerequisite steps, so it falls short of full alternative/exclusion coverage.

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