Post Instances Customers

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

Annotations already declare readOnlyHint=false and destructiveHint=false, so safety is covered by structured data; the description still adds real operational detail: the post-create state ('kyc_status verifying'), development auto-approval, and the file-fetching contract ('HTTPS URLs that BlindPay downloads, so they must be publicly fetchable; data: URIs are rejected'). It does not discuss retry/idempotency behavior despite a mutable create, so it is not exhaustive.

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 the core action and prerequisite, then requirement lists per customer type; every sentence carries information about a conditional rule. The dense comma-separated field enumerations are needed for correctness but make it visually heavy.

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 create call with a deeply nested body, 33% schema coverage, and no output schema, the description supplies the conditional required-field logic and validation constraints an agent needs to construct a valid request. It does not describe the response payload (e.g., returned customer id or object shape), which is the main remaining gap since no output schema exists.

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 only 33%, so the description must compensate, and it does by enumerating required field sets per branch (individual/standard vs business/standard, including owners and document fields) and adding a format rule ('US state_province_region is a two-letter code'). Optional fields such as latitude/longitude, account_purpose, and additional_info are left to schema descriptions, so coverage is not complete.

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 ('Creates a customer') plus the outcome ('starts KYC (individuals) or KYB (businesses)'), which cleanly separates it from the read/update/delete customer siblings in the list. An agent can identify the operation 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 concrete prerequisite chain ('Send the tos_id the customer received after accepting terms of service (see Initiate Terms of Service)') and states which kyc_type/type combinations are valid ('light is not available, and businesses only support standard'), effectively defining when this tool applies. It stops short of naming sibling tools to use instead, so it is strong context rather than explicit alternative routing.

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