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

With no annotations, the description carries the whole burden and does real work: it discloses that the key is shown only once, must be persisted across workspace resets, doubles as the MCP connection credential, and that a claim_url + e-mail give a recovery path. It does not cover failure behavior (handle already taken, invalid invite, rate limits) or whether repeated calls create duplicate accounts.

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?

Three sentences, each doing distinct work — what it returns, how to persist and reuse it, and the human hand-off for claim_url. Front-loaded with the core action; the only friction is the unexplained 'claim_url' token and the bare 'battle.training/account' path, which assume context.

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 must explain returns, and it does: a once-shown key and a claim_url to surface to the human. Combined with a fully described 3-parameter schema this is nearly sufficient, with error/repeat-call behavior the main omission.

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 handle, email, and invite are already fully documented in the schema, and the description adds no syntax or constraint detail beyond that. The only added semantics relate to outputs (key, claim_url), not parameters, so the baseline of 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?

The description states a specific verb and resource ('Create an account') and immediately names the concrete artifact produced ('receive its key'). That is clearly distinct from siblings such as create_bot, whoami, or get_started, so an agent can route to it without opening the 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?

The text makes the follow-up path explicit ('pass it as `key` to later tools or set Authorization: Bearer <key>'), which strongly implies this is the onboarding prerequisite for other tools. It stops short of naming an alternative for the already-accounted case (e.g. whoami) or stating what to do if a key already exists, so no explicit when-not guidance is given.

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