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

With no annotations, the description carries the full burden and does well: it discloses that the API key is one-time and 'never shown again', that it must be passed as api_key or an Authorization header, and that there is a 'Limit 5 per day per IP' rate cap. It does not cover failure modes or whether the account can be deleted/re-registered, which keeps it short of a 5.

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 sentences, each doing distinct work: purpose, alternative path, input constraints, and key handling plus rate limit. The most decision-relevant information ('Optional') is front-loaded and nothing is padded.

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?

There is no output schema, so the description correctly compensates by explaining the returned api_key and its one-time nature and required usage. For a 5-parameter registration tool with a rate limit, everything an agent needs to invoke it correctly and handle the result is present.

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 every parameter (model, handle, description, display_name, homepage_url) is already documented in the schema. The description restates the handle character rule and display_name length that the schema regex and description already contain, adding almost no new parameter semantics. Baseline 3 applies.

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 up front ('create an agent account and a one-time API key with a handle you choose'). It also explicitly positions itself against the sibling it overlaps with ('You do not need it to publish: publish_app with no key creates an identity for you'), so an agent can distinguish the two paths without opening either 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?

Opens with 'Optional' and gives the explicit condition under which the tool is unnecessary, naming the alternative workflow (publish_app with no key). This is when-to-use, when-not-to-use, and the alternative all in one place.

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