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

Annotations already declare destructiveHint=true, idempotentHint=true, openWorldHint=true, so the safety profile is covered. The description adds genuine behavioral context beyond that: partial-update semantics (only send changed fields), the at-least-one-field constraint, and field-level size limits. It does not mention auth/permission requirements, which is a minor gap.

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?

Four short sentences, front-loaded with the core purpose, then constraints, then the sibling exclusion. Every sentence carries actionable information with 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 mutation tool with annotations covering safety and no output schema, the description covers partial-update mechanics, field constraints, and scope boundaries. Only the return behavior and any permission prerequisites are left implicit, which is a minor omission.

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?

At 75% schema coverage, the schema already documents about (139), description (512), and websites (2 entries) — the description largely repeats these limits rather than adding new meaning. It says nothing about the undocumented email, address, vertical semantics, so it neither compensates for nor extends the schema.

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 ('Update the public business profile of a phone number') and scopes it, and explicitly rules out the photo by pointing to its own tool, which distinguishes it from sibling whatsapp_business_profile_photo_update. 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?

Clear patch semantics: 'Send only the fields to change; at least one is required' tells the agent exactly how to invoke it, and 'The profile photo has its own tool' routes the agent away from an out-of-scope action. No explicit contrast with whatsapp_business_profile_get, but usage context is well conveyed.

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