Send an SMS message to multiple recipients in E.164 format at once (up to 100 recipients).
| Name | Required | Description | Default |
|---|---|---|---|
| message | Yes | Text content of the SMS | |
| sender_id | No | Optional approved custom Sender ID | |
| recipients | Yes | Array of recipient phone numbers in E.164 format (+212600000000) |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations present, the description carries the full burden. It discloses the recipient limit (up to 100) and the E.164 format requirement, which is useful. However, it does not mention delivery semantics, error handling, partial failures, asynchronous behavior, or costs—gaps that matter for a bulk-sending tool.
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?
A single, front-loaded sentence conveys the core action, the recipient scope, the format, and the limit with zero wasted words. Every phrase earns its place.
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 simple input schema and the clear sibling landscape, the description is sufficient for selection and invocation. It lacks details about response shape or failure behavior, but the tool's simplicity partly compensates. It could be more complete by noting when to use send_sms instead.
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 100%, so the schema already documents all parameters. The description enhances the semantics by emphasizing the bulk nature ('at once') and the hard limit of 100 recipients, which is not visible in the schema. This adds value beyond the structured fields.
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 uses a specific verb and resource: 'Send an SMS message to multiple recipients.' It also highlights 'at once' and a recipient cap, which clearly distinguishes this from the sibling send_sms tool. An agent can tell it apart 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?
The description clearly implies the intended use case: sending to multiple recipients at once, up to 100. It does not explicitly name send_sms as the alternative for single recipients, nor does it state when not to use this tool, so it falls short of a full 5.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Tools split into clear clusters: customer-facing send/verify/get tools and admin ops tools. The three ops_* tools could initially seem similar, but their descriptions distinguish operational alerts, business health, and route quality. Minor overlap exists between ops_monitoring and ops_pulse, but overall boundaries are clear.
The set uses consistent prefixes: get_, send_, verify_, and ops_. This creates a predictable pattern for agents. Minor deviation is that ops_pulse and ops_route_quality are noun-style rather than verb-noun, and 'pulse' is less descriptive than the others.
Eight tools is well-scoped for an SMS/OTP server, covering customer actions, pricing/balance, and admin oversight without bloat. Each tool has a clear role and the count feels appropriate for the domain.
Core flows are covered: balance lookup, pricing, sending SMS, OTP lifecycle, and admin monitoring. A notable gap is lack of per-message delivery status or send history, but agents can still complete the primary send-and-verify workflows. Minor gaps exist but are workable.