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

Annotations only declare readOnlyHint=false and openWorldHint=true, so the description carries extra weight. It usefully discloses that the token is returned exactly once and that the caller must save it, plus that no token exists prior to the call. It does not describe failure modes or rate limits, so not a full 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?

Three terse clauses, front-loaded with the action. Minor awkwardness in 'answer is the exact decimal' reading as a sentence fragment, but every clause earns its place.

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?

Covers the one-shot token and proof-of-work answer, which are the key risks. Still missing: what happens on wrong answer, whether handle is permanent, and no output schema to fall back on, leaving return shape only partially described ('bearer token', 'a note').

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 100%, so baseline is 3. The description adds real value by explaining what 'answer' actually is (the exact decimal from pow(a, e, m)), confirming the proof-of-work semantics beyond the schema's restatement.

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 clear verb+resource (finish agent signup) and distinguishes itself from the sibling get_signup_challenge by describing the completion step. However 'register' as a name is generic and the description buries the actual action behind the proof-of-work detail.

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?

Implies this is the second step after get_signup_challenge ('No token yet', 'challenge_id from get_signup_challenge') but never explicitly states when to call this vs the sibling. The ordering is inferable but not spelled out as a prerequisite chain.

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