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

Annotations already mark this destructive/openWorld/non-idempotent, and the description adds the crucial context that a postcard is physically mailed, takes 5-14 days, and that confirm=false previews versus confirm=true actually triggers the irreversible send. That confirm-gate semantics is exactly the added value structured fields don't convey.

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, then method semantics, then the SAFETY block last. Dense and heavily punctuated but each sentence carries real information; only minor tightening possible.

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?

With an output schema present, return values needn't be described. The description covers the action, its method choices, prerequisite tool, follow-up tool, latency, and the destructive-confirm contract, so an agent has everything needed to invoke it correctly.

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 0%, so the description carries the burden. It defines the method enum values (ADDRESS/PHONE_CALL/SMS/EMAIL/AUTO), explains mailer_contact, and clarifies the confirm flag. It leaves email, phone, and location unexplained, which keeps it short of a 5.

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 (STARTS verification) and resource (business listing), plus the downstream effect (becomes visible on Maps/Search). It is clearly distinguishable from the sibling gbp_verification_options (which lists methods) and gbp_complete_verification (which enters the PIN).

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?

Explicitly routes the agent: 'Use only a method returned by gbp_verification_options' and 'enter the PIN with gbp_complete_verification'. Both the precondition and the follow-up sibling are named rather than implied.

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