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

Annotations cover the safety profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=true), so the description's job is to add operational context — and it does: codes expire in 10 minutes, attempts are limited, and success returns a short-lived identity token. It stops short of saying what happens on failure (error shape, whether the verificationId is burned after N attempts), which is the one remaining gap for a non-idempotent call.

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 sentences, front-loaded with the action and its inputs, then the outcome and constraints. Every clause earns its place: nothing is restated from the title and no filler is present.

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, no-output-schema verification step, the description supplies the prerequisite tool, the credential format, the expiry window, the retry limit, and the downstream token consumers. An agent has everything needed to invoke it correctly in sequence.

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 100%, so both parameters already carry their own descriptions in the schema, and the description largely restates them ("pass the verificationId from vivid_identity_start and the 6-digit code"). Baseline 3 applies — the description reinforces provenance but adds no format or validation detail 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?

Names a specific verb and resource ("Complete email verification") and immediately scopes it to the two inputs, the verificationId from vivid_identity_start and the 6-digit code. It also distinguishes itself from siblings by naming the downstream tools it unlocks (vivid_reorder, vivid_order_status), so an agent can place it in the flow without reading any schema.

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 states the prerequisite chain (verificationId must come from vivid_identity_start) and the success condition that gates other tools. The expiry and attempt-limit notes tell the agent when the call must happen and when to retry versus restart, which is exactly the routing information needed.

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