Bring Sms Marketing
to LlamaIndex
Learn how to connect String to LlamaIndex and start using 10 AI agent tools in minutes. Fully managed, enterprise secure, and ready to use without writing a single line of code.
What is the String MCP Server?
Connect your String account to any AI agent and manage business messaging.
What you can do
- Contact Management — List, view, and create contacts
- Messaging — Send SMS and MMS messages to any phone number
- Conversation Tracking — View message history and active threads
- Campaign Management — List SMS marketing campaigns
- Tag Organization — View contact tags for segmentation
- Health Check — Verify API connectivity
Built-in capabilities (10)
Verify API connectivity
Create a contact
Get contact details
Get message details
List campaigns
List all contacts
List conversations
List messages
List all tags
Send a text message
Why LlamaIndex?
LlamaIndex agents combine String tool responses with indexed documents for comprehensive, grounded answers. Connect 10 tools through Vinkius and query live data alongside vector stores and SQL databases in a single turn. ideal for hybrid search, data enrichment, and analytical workflows.
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Data-first architecture: LlamaIndex agents combine String tool responses with indexed documents for comprehensive, grounded answers
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Query pipeline framework lets you chain String tool calls with transformations, filters, and re-rankers in a typed pipeline
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Multi-source reasoning: agents can query String, a vector store, and a SQL database in a single turn and synthesize results
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Observability integrations show exactly what String tools were called, what data was returned, and how it influenced the final answer
String in LlamaIndex
String and 3,400+ other MCP servers. One platform. One governance layer.
Teams that connect String to LlamaIndex through Vinkius don't need to source, host, or maintain individual MCP servers. Every tool call runs inside a hardened runtime with credential isolation, DLP, and a signed audit chain.
Raw MCP | Vinkius | |
|---|---|---|
| Server catalog | Find and host yourself | 3,400+ managed |
| Infrastructure | Self-hosted | Sandboxed V8 isolates |
| Credential handling | Plaintext in config | Vault + runtime injection |
| Data loss prevention | None | Configurable DLP policies |
| Kill switch | None | Global instant shutdown |
| Financial circuit breakers | None | Per-server limits + alerts |
| Audit trail | None | Ed25519 signed logs |
| SIEM log streaming | None | Splunk, Datadog, Webhook |
| Honeytokens | None | Canary alerts on leak |
| Custom domains | Not applicable | DNS challenge verified |
| GDPR compliance | Manual effort | Automated purge + export |
Why teams choose Vinkius for String in LlamaIndex
The String MCP Server runs on Vinkius-managed infrastructure inside AWS — a purpose-built runtime with per-request V8 isolates, Ed25519 signed audit chains, and sub-40ms cold starts. All 10 tools execute in hardened sandboxes optimized for native MCP execution.
Your AI agents in LlamaIndex only access the data you authorize, with DLP that blocks sensitive information from ever reaching the model, kill switch for instant shutdown, and up to 60% token savings. Enterprise-grade infrastructure, zero maintenance.

* Every MCP server runs on Vinkius-managed infrastructure inside AWS - a purpose-built runtime with per-request V8 isolates, Ed25519 signed audit chains, and sub-40ms cold starts optimized for native MCP execution. See our infrastructure
How Vinkius secures
String for LlamaIndex
Every tool call from LlamaIndex to the String MCP Server is protected by DLP redaction, cryptographic audit chains, V8 sandbox isolation, kill switch, and financial circuit breakers.
Frequently asked questions
Can my AI send text messages?
Yes. Use send_message with the recipient phone number and message text. The agent delivers it via String.
Can I view conversation history?
Yes. list_conversations shows all active threads, and list_messages returns full message history.
Can I create contacts through the AI?
Yes. create_contact adds a new contact with name and phone number to your String directory.
How does LlamaIndex connect to MCP servers?
Use the MCP client adapter to create a connection. LlamaIndex discovers all tools and wraps them as query engine tools compatible with any LlamaIndex agent.
Can I combine MCP tools with vector stores?
Yes. LlamaIndex agents can query String tools and vector store indexes in the same turn, combining real-time and embedded data for grounded responses.
Does LlamaIndex support async MCP calls?
Yes. LlamaIndex's async agent framework supports concurrent MCP tool calls for high-throughput data processing pipelines.
BasicMCPClient not found
Install: pip install llama-index-tools-mcp
