Skip to main content
Glama
UltraStarz
by UltraStarz

send_sms

Send a transactional SMS to a US phone number for $0.03 USDC, with automatic opt-out text and required consent attestation. Use for alerts, reminders, and order updates.

Instructions

Send one transactional SMS message to a US phone number. Costs $0.03 USDC per message, paid automatically from the configured wallet on Base Sepolia (testnet during beta, will flip to Base mainnet at launch). Messages are sent from a Twilio toll-free number and automatically get 'Reply STOP to opt out' appended if not already present. CRITICAL — only call this tool when ALL of the following are true: (1) the user has explicitly asked to text someone, or has previously set up an automation that texts; (2) the recipient is the user themselves OR someone the user has confirmed has consented to receive texts from this automation; (3) the content is transactional or informational (order updates, alerts, reminders, 2FA, agent task completion notifications) — NOT marketing, promotion, or unsolicited outreach. If unsure whether the recipient consented, ASK the user before calling. Setting opt_in_attestation: true is the operator's (user's) legal attestation that consent was obtained — it is not a no-op flag. Use cases: 'text me when the long-running task finishes', 'send Mom an order confirmation for the gift I just bought her', 'remind me at 3pm to call the dentist by texting my cell'.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
toYesRecipient phone number in E.164 format: +1XXXXXXXXXX (US only).
messageYesSMS body. 1-1600 characters. Will be automatically suffixed with ' Reply STOP to opt out.' if no opt-out language is present.
opt_in_attestationYesMust be true. Operator's attestation that the recipient has consented to receive this message. Setting this to true when the recipient has NOT consented is a TCPA violation and exposes the operator to statutory damages.
Behavior5/5

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

With no annotations provided, the description carries full burden and excels: it discloses per-message cost ($0.03 USDC), wallet network (Base Sepolia/testnet), Twilio toll-free sending, automatic opt-out suffix append, and the legal significance of opt_in_attestation. No behavioral trait is hidden.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is longer than average, but every sentence adds necessary context (cost, source number, legal attestation, use cases). It is front-loaded with purpose and structured with a clear warning block. Slightly verbose but fully justified given the compliance stakes.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with no output schema and no annotations, the description is unusually complete. It covers purpose, cost, network, sender, opt-out behavior, consent requirements, and concrete examples. The only omission is return value format, but that is not essential for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3. The description adds some color about opt_in_attestation ('not a no-op flag') and the opt-out suffix behavior, but these are largely repeated from the schema descriptions. The description does not materially reduce ambiguity beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb+resource: 'Send one transactional SMS message to a US phone number.' It clearly distinguishes transactional messaging from other types and specifies the US-only scope. Even without sibling tools, it fully communicates what the tool does.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The CRITICAL section explicitly enumerates all four conditions for safe usage, includes examples of appropriate versus prohibited content, and instructs the agent to ask the user when consent is uncertain. This is model when-to-use guidance with clear exclusions.

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

Install Server

Other Tools

Latest Blog Posts

MCP directory API

We provide all the information about MCP servers via our MCP API.

curl -X GET 'https://glama.ai/api/mcp/v1/servers/UltraStarz/x402-sms-mcp'

If you have feedback or need assistance with the MCP directory API, please join our Discord server