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

Annotations only declare the write/non-idempotent/non-destructive profile, but the description goes well beyond: no auth required, the key is returned once and cannot be retrieved again, unverified rate limits (60/hour, 400/day, one key), what verification unlocks, and the no-reissue behavior that confirms the non-idempotent hint. This is exactly the operational context the annotations can't carry.

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 with purpose and precondition, then consent rules, then limits and verification, then the edge case — a logical order with no filler sentences. It is dense but the bulk (policy URLs and consent wording) is legally load-bearing rather than padding.

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 one-shot account-creation tool with an output schema already covering the return payload, the description supplies everything an agent needs: preconditions, consent handling, rate-limit consequences, verification path, and the duplicate-email edge case. Nothing relevant 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 coverage is 100%, so all three parameters are already documented, including the full accept_terms consent text that the description repeats verbatim. The description adds 'from an email' framing but no syntax or format guidance beyond the schema. 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?

States a specific verb+resource — 'Create a Recall Kitchen account and API key from an email' — and immediately establishes the precondition that no API key or x402 payment is required, which is exactly the blocker an agent might otherwise assume. The closing note that it won't re-issue a key for an existing email implicitly separates it from create_api_key, which manages keys for accounts that already exist.

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 operating conditions: set accept_terms true only after the person confirms 13+ and accepts the three policies, never automatically. It also explains the verification path (sign in at app.recallkitchen.com with the same email) and the 'when-not' case (email already has an account). It stops short of naming create_api_key as the alternative for existing accounts.

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