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

With no annotations, the description carries the full burden and mostly succeeds: it discloses that provisioning is instant and requires 'no human steps' (i.e. no interactive auth flow), quantifies the tier tradeoff (~100 vs ~50 credits/day), and describes what is returned and how to persist it. It omits key lifecycle behavior — expiry, revocation, whether repeat calls mint additional keys, and any rate limit on creation.

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 earning its place: what it does, the parameter tradeoff, and how to use the return value. Front-loaded with the core action and no 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 one-optional-parameter tool with no output schema, the description covers the essentials — what gets created, the tier difference, and that a key is returned and should be reused. The remaining gap is credential lifecycle (multiple keys, expiry/revocation), which matters because the tool mints long-lived secrets.

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, but the description adds concrete meaning the schema lacks: it quantifies the benefit of the email parameter (~100 credits/day vs ~50/day) rather than just saying 'larger free tier'. It does not describe any validation or format constraints on the email, though the schema notes the verification link.

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 — 'Provision a new Auto-Reader OCR API key' — which is instantly distinguishable from every sibling (extract_document, ocr_image, translate_text, etc.) that operate on documents rather than credentials. An agent can identify the tool's role 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 a conditional usage rule for the one parameter ('Pass an optional email to unlock the larger free tier') and instructs how to use the result ('Store the returned key and pass it as api_key on future calls'). There is no competing alternative to route away from, so the absence of exclusions is reasonable, but it never states when NOT to call it (e.g. if a key already exists).

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