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

Annotations only declare the operation is not read-only and not idempotent; the description goes well beyond by disclosing side effects (a confirmation email is sent), a gated capability (applying blocked until confirmation), and commercial terms (7-day/5-application trial, then Starter/Pro pricing). That is exactly the extra context annotations cannot carry.

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 and outcome, with prerequisites and post-conditions following logically. The pricing/tier sentence is the longest and least essential for invoking the tool, though it does inform downstream expectations.

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?

No output schema exists, and the description covers the return value (an API key), the confirmation-email flow, and usage limits — everything an agent needs to call this correctly and set expectations.

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 must compensate; it gives real meaning to accept_terms (acceptance of Terms/Privacy plus authorization to apply on the user's behalf) and implies email is where confirmation is sent. The password parameter is left entirely to the schema, so it does not fully close the coverage gap.

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 ('Register a new Keywordise account') and adds the concrete outcome ('receive an API key for it'), which cleanly separates it from the sibling login tool.

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?

Conveys when this applies (new account registration, requires accept_terms=true) and what follows (confirmation email, applying opens after confirmation). It does not explicitly say 'use login instead if you already have an account', so sibling routing is implied rather than stated.

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