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

Annotations already declare destructiveHint=true, so the mutation risk is flagged structurally. The description adds genuinely useful context beyond that: 'Only the fields you pass are sent' tells the agent this is a partial update rather than a full replace. However, it never reconciles the destructive hint, says nothing about clearing fields, required permissions, or what an invalid customer_id does.

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 short sentences with the field list and the key partial-update rule front-loaded; every sentence earns its place. The trailing API route is minor but harmless metadata for agents that recognize the Housecall Pro surface.

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 12-parameter mutation with no output schema and 33% schema coverage, the description covers the mutable field surface and the partial-update contract, which is the most important thing. It still leaves permission requirements, error behavior, and null/clearing semantics unspecified.

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% (tags, company, customer_id, notifications_enabled), but the description names most of the gap: name, contact details, lead source, notes, notification setting. That partially compensates without giving format or validation detail, and parameters like home/work/mobile_number are only loosely implied by 'contact details'.

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 clear verb ('Change') plus the resource ('a customer') and enumerates the mutable fields, so its purpose is unambiguous against siblings like housecall_create_customer or housecall_get_customer. It stops short of explicitly contrasting itself with the sibling that also edits customer data, but the verb makes routing obvious.

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?

There is no when-to-use guidance, no prerequisites (e.g. needing an existing customer_id or lookup via housecall_get_customer first), and no exclusions. The closest thing to guidance is the partial-update note, which is behavioral rather than a usage rule.

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