send_custom_message

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

Annotations already flag this as non-read-only and destructive; the description adds a meaningful behavioral guardrail: the tool requires explicit confirmation before sending. It does not detail other side effects, but the confirmation requirement is valuable context beyond the annotations.

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?

The description is a single compact sentence with no filler, and the primary action is front-loaded. However, the terseness leaves little room for parameter or context detail, so it is concise but minimal.

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?

Given the destructive nature, three parameters, a nested message object, and zero schema parameter descriptions, this one-line description is insufficient. It omits message structure, confirmation mechanics, and any success/failure behavior, even though an 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 0%, so the description must compensate, but it only touches the confirm parameter ('must explicitly confirm'). It provides no semantics for openid or the message object, leaving the agent to infer their meaning from names alone.

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?

The description identifies a specific action and resource: sending a customer-service message. This distinguishes it from sibling send tools like send_template_message or send_subscribe_message by message type, though it does not name those alternatives explicitly.

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 description offers no guidance on when to use this tool versus the many sibling messaging/send tools. The only usage-related cue is the requirement for explicit confirmation, which is a precondition rather than a selection criterion.

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