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

Annotations already declare the non-read-only, non-destructive, open-world profile. The description goes beyond that by disclosing the keyless-vs-keyed access model and the human claim/payment gate for restyle and localize, plus surfacing the claim_url handoff. It stops short of rate limits or return shape, but adds meaningful context.

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?

Four tight sentences with the core action front-loaded. Each sentence carries workflow information rather than filler, though the access-tier breakdown is slightly list-like.

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 no output schema, the description helpfully implies the claim_url handoff and explains the operational tiering an agent must understand before calling. For a one-optional-param create tool with annotations present, this is close to complete.

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 the single optional 'name' parameter is fully documented in the schema. The description adds no parameter-level detail, which is the expected baseline when the schema does the work.

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 ('Create an agent API key') and immediately clarifies the unusual 'without an account' condition. It does not explicitly contrast with sibling tools, but the operation is unmistakable.

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 conditional guidance on when the key matters versus not: directory browse needs no key, screenshot lookup works immediately, while restyle and localize require a human to claim and pay. This routes the agent on whether it even needs this tool, though it doesn't compare to named siblings.

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