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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false and destructiveHint=false, so the description gets a lower bar. It still adds genuinely non-schema context: the raw key is returned exactly once and cannot be recovered, the sandbox key is never billed and has no /research access, the live key carries a $1.00 starter credit, and minting is rate-limited to 10 keys per address per day. Note: the scoring rubric's 1-5 mid-point is 'adequate', and this sits at that level given the annotations already carry the mutation/safety signal.

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?

Front-loaded and dense: the anonymous-key carve-out and the two-mode split come first, with operational details after. Some repetition blunts it — 'the raw key is returned once' and 'the raw key is in the result once' say the same thing, and sibling-minting is stated twice (rotation clause and the closing 'With a key already configured' sentence).

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?

No output schema exists, and the description compensates by telling the agent what comes back (a raw dv_sk_test_/dv_sk_live_ key, shown once) and what to do with it (Authorization: Bearer, or re-add the server with that header). For a 2-param, zero-required creation tool, nothing an agent needs to invoke it correctly is missing.

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 baseline would be 3, but the description adds meaning beyond the schema: the email is explicitly a contact label rather than a credential, and the billing consequence of omitting it (never-billed sandbox, no /research) is spelled out. `label` is not discussed in the description, which the schema already covers.

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 (mint an API key) and immediately decomposes it into the three distinct modes the tool supports: anonymous sandbox key, live key via email, and sibling/rotation key via existing bearer. An agent can distinguish this from keys_me or any credential sibling 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?

Gives explicit selection rules: send {} for a sandbox key, send {"email":"…"} for a live prepaid account key, send an existing key as bearer to mint a sibling for rotation. It also names the exclusion up front ('the one endpoint that needs no key') and states the condition under which credentials are required.

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