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

With no annotations, the description carries the full behavioral burden and does so well: it discloses the proof-of-work gate (12 leading zero bits), the nonce format constraint, the rate limit (five keys per IP per UTC day), the auth exemption (no Bearer token or payment), and critically the irreversible return behavior ('returned once,' only the SHA-256 hash stored). These are exactly the traits an agent cannot infer from the schema.

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?

It is a tight block of high-value sentences, front-loaded with the action and followed by the hard constraint (pow_nonce) and the operational limits. Minor redundancy exists where the pow_nonce rule is repeated verbatim from the schema, which costs a point, but nothing here is filler.

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?

For a creation tool with no output schema and no annotations, the description covers everything an agent must know: input constraints, auth requirements, rate limits, and the one-time nature of the returned secret plus what is persisted. Nothing material is left unstated.

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 all three parameters are already documented in the schema, including the full pow_nonce rule. The description restates the nonce requirement and the optionality of email/name rather than adding new meaning such as date-format edge cases or how name is used server-side. Baseline 3 applies when the schema does the heavy lifting.

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 opens with a specific verb+resource: 'Create a free-tier API key with no human approval,' which is unambiguous about the action and the artifact produced. It loses a point because the tool name 'get_api_key' implies retrieval, so the description is silently correcting the name rather than the name and description reinforcing each other. No sibling differentiation is needed since 'consensus' and 'judge' are unrelated.

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?

It gives clear operating context an agent needs before calling: no human approval, no Bearer token, no payment, and a free tier. It does not state when NOT to use it or point to any alternative for key management, but the surrounding siblings make that unnecessary. This is solid context without explicit exclusions.

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