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

Annotations already declare the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false, openWorldHint=true). The description adds the requirement that at least one field be supplied, which is genuinely useful behavioral context, but it says nothing about permissions/auth needs or what happens to fields left unset.

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?

Two short sentences, zero waste, with the action and its target front-loaded and the constraint immediately following. Nothing is redundant with the structured fields.

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 6-parameter mutation with annotations but no output schema, the description covers the core action and the at-least-one rule but omits permission requirements and the result of the update. Adequate but with clear gaps for a mutating tool.

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 67%, and the description restates the three optional editable fields while conveying the 'and/or' optionality and the at-least-one constraint, which the schema does not express. It adds no meaning for the three required identifiers (profile_id, phone_number_id, group_id) and no value semantics for the enum, so this is a baseline-level contribution.

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 (change a WhatsApp group) and enumerates the exact mutable fields (subject, description, join_approval_mode), which cleanly separates it from whatsapp_group_create, whatsapp_group_delete, and whatsapp_group_get. It stops short of naming any sibling explicitly, so it is clear but not sibling-differentiating.

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?

The phrase 'At least one is required' gives a real precondition for invoking the tool, which is useful. However, there is no guidance on when to prefer this over adjacent tools such as whatsapp_group_participants_add or whatsapp_group_join_requests_approve, so usage is only implied.

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