JustCall MCP Server
for AI Agents
Connect your AI agent to StackOne's JustCall MCP server and give it 88 MCP tools out of the box. Auth, tool execution, and security all managed.
StackOne 
Coverage
88 Agent Actions
Create, read, update, and delete across JustCall — and extend your agent's capabilities with custom actions.
Authentication
Agent Tool Authentication
Per-user OAuth in one call. Your JustCall MCP server gets session-scoped tokens with zero credentials stored on your infra.
Agent Auth →
Security
Agent Protection
Every JustCall tool response scanned for prompt injection in milliseconds — 88.7% accuracy, all running on CPU.
Prompt Injection Defense →
Performance
Max Agent Context. Min Cost.
Free up to 96% of your agent's context window to enhance reasoning and reduce cost, on every JustCall call.
Tools Discovery →What is the JustCall MCP Server?
A JustCall MCP server lets AI agents read and write JustCall data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's JustCall MCP server ships with 88 pre-built actions, fully extensible via the Connector Builder — plus managed authentication, prompt injection defense, observability, and agent execution runtime. Connect it from MCP clients like Claude Desktop, Claude Code, Cursor, Goose, and VS Code, or from agent frameworks like OpenAI Agents SDK, LangChain, and Vercel AI SDK.
All JustCall MCP Tools
Every action from JustCall's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.
Appointments
- Create Appointment
Create a new appointment in the calendar.
- Get Appointment
Retrieve details of a specific appointment by ID.
Calls
- List Calls
Retrieve a paginated list of all calls with optional filtering by date, agent, direction, type, and more.
- Get Call
Retrieve details of a specific call by its ID.
- Update Call
Update notes or rating for a specific call.
Contacts
- Create Contact
Create a new contact with name, phone, email, and other details.
- List Contacts
Retrieve a paginated list of all contacts with optional filtering.
- Get Contact
Retrieve details of a specific contact by ID.
- Update Contact
Update an existing contact's information.
- Delete Contact
Delete a contact by ID or phone number.
Unified Groups
- List Unified Groups
List unified groups in JustCall.
- Get Unified Group
Get a unified JustCall group by ID.
Unified Organizations
- List Unified Organizations
List unified organizations in JustCall.
- Get Unified Organization
Get a unified JustCall organization by ID.
Unified Roles
- List Unified Roles
List unified roles in JustCall.
- Get Unified Role
Get a unified JustCall role by ID.
Unified Users
- List Unified Users
List unified users in JustCall.
- Get Unified User
Get a unified JustCall user by ID.
Phone Numbers
- List Phone Numbers
Retrieve a paginated list of all phone numbers in the account.
- Get Phone Number
Retrieve details of a specific phone number by ID.
Sales Dialer Calls
- List Sales Dialer Calls
Retrieve a paginated list of all Sales Dialer calls.
- Get Sales Dialer Call
Retrieve details of a specific Sales Dialer call by ID.
Campaigns
- Create Campaign
Create a new Sales Dialer campaign.
- List Campaigns
Retrieve all Sales Dialer campaigns.
- Get Campaign
Retrieve details of a specific Sales Dialer campaign.
- Update Campaign
Update an existing Sales Dialer campaign.
Sales Dialer Contacts
- Create Sales Dialer Contact
Create a new Sales Dialer contact.
- List Sales Dialer Contacts
Retrieve all Sales Dialer contacts.
- Get Sales Dialer Contact
Retrieve details of a specific Sales Dialer contact.
- Update Sales Dialer Contact
Update an existing Sales Dialer contact.
- Delete Sales Dialer Contact
Delete a Sales Dialer contact by ID.
Texts
- List Texts
Retrieve a paginated list of all SMS and MMS messages.
- Get Text
Retrieve details of a specific text message by ID.
Tags
- Create Tag
Create a new tag for SMS categorization.
- List Tags
Retrieve all SMS tags in the account.
- Get Tag
Retrieve details of a specific SMS tag.
- Delete Tag
Delete an SMS tag by ID.
Threads
- List Threads
Retrieve all SMS conversation threads.
- Get Thread
Retrieve a specific SMS conversation thread with its messages.
Users
- List Users
Retrieve a paginated list of all agents/users in the account.
- Get User
Retrieve details of a specific user/agent by ID.
User Groups
- Create User Group
Create a new user group (team) in the account.
- List User Groups
Retrieve all user groups (teams) in the account.
- Get User Group
Retrieve details of a specific user group by ID.
- Update User Group
Update an existing user group's name, extension, or members.
- Delete User Group
Delete a user group by ID.
Messages
- Send Message
Send a text, template, or media WhatsApp message.
- List Messages
Retrieve a paginated list of all WhatsApp messages.
- Get Message
Retrieve details of a specific WhatsApp message by ID.
Other (39)
- Add Contact To Campaign
Add a contact to a Sales Dialer campaign.
- Send SMS/MMS
Send an SMS or MMS message to a phone number.
- Add Tag To Thread
Add a tag to a JustCall number and contact conversation thread.
- Add URL To Webhook
Subscribe a URL to receive webhook events.
- List Calls AI Data
Retrieve AI analysis data for calls including sentiment, scores, and summaries.
- Get Call AI Data
Retrieve AI analysis data for a specific call.
- List Meetings AI Data
Retrieve AI analysis data for meetings.
- Get Meeting AI Data
Retrieve AI analysis data for a specific meeting.
- List Available Slots
Retrieve available scheduling slots for appointments.
- Get Call Journey
Retrieve the sequential journey stages showing how a call was routed.
- Get Call Voice Agent Data
Retrieve AI Voice Agent insights and actions executed during a call.
- Download Call Recording
Download the MP3 recording file for a completed call.
- Get Account Analytics
Retrieve account-level call analytics including SLA, connect rate, and durations.
- Get Agent Analytics
Retrieve per-agent call performance metrics.
- Get Number Analytics
Retrieve per-phone-number call metrics.
- List Blacklisted Contacts
Retrieve all contacts on the blacklist, DND, or DNM lists.
- Get Unified Credentials
Get the current JustCall connection's unified credentials and identity.
- List Unified Resource Types
List unified resource types in JustCall.
- List Unified Resource Users
List unified resource users in JustCall.
- List Campaign Contacts
Retrieve all contacts in a specific campaign.
- Get Bulk Import Status
Check the progress of a bulk contact import.
- List Sales Dialer Contact Custom Fields
Retrieve the custom field schema for Sales Dialer contacts.
- Get Sales Dialer Agent Analytics
Retrieve agent and campaign performance metrics for Sales Dialer.
- List Voice Agents
Retrieve all configured AI Voice Agents.
- List Subscribed Webhooks
Retrieve all subscribed webhook events.
- List Templates
Retrieve all approved WhatsApp message templates.
- Update Contact Status
Add or remove a contact from blacklist, DND, or DNM lists.
- Update User Availability
Update an agent's availability status for call routing.
- Remove Contact From Campaign
Remove a contact from a Sales Dialer campaign.
- Remove Tag From Thread
Remove a tag from a conversation thread.
- Remove URL From Webhook
Remove a URL from a webhook subscription.
- Bulk Add Contacts To Blacklist
Bulk add contacts to DND, DNM, or blacklist.
- IAM Auth Test
Validate the current JustCall API key/secret pair and return the raw, unmapped /v2.1/users response (first page, single record). Use this when troubleshooting credential validity or API connectivity, not for normal app flows.
- Detect Incoming Number
Detect phone number type (Mobile, Landline, VOIP) and carrier.
- Bulk Import Sales Dialer Contacts
Bulk import contacts to the Sales Dialer.
- Bulk Add Contacts To DNCA
Bulk add contacts to the Do Not Call Again list. contact_ids and contact_numbers are mutually exclusive — provide only one per request.
- Check Reply
Check the most recent inbound SMS reply from a contact.
- Initiate Call
Trigger an outbound call from an AI Voice Agent.
- Check Message Reply
Check if a WhatsApp reply has been received from a contact.
JustCall AI Agent Use Cases
Connect your AI agent to JustCall and help your team scale the sales operations they run by hand today.
Use StackOne to connect your AI agent to your CRM, email, and calendar tools to automate post-demo follow-up.
ViewUse StackOne to connect your AI agent to your CRM, email, and calendar tools to automate deal risk scoring and pipeline alerts.
ViewUse StackOne to connect your AI agent to your CRM, sales engagement, and messaging tools to automate outbound prospecting.
ViewSet Up Your JustCall MCP Server in Minutes
One endpoint. Any framework. Your agent is talking to JustCall in under 10 lines of code.
Agent Frameworks
JSON{
"mcpServers": {
"stackone": {
"command": "npx",
"args": [
"-y",
"mcp-remote@latest",
"https://api.stackone.com/mcp?x-account-id=<account_id>",
"--header",
"Authorization: Basic <YOUR_BASE64_TOKEN>"
]
}
}
}Platform Resources
MCP Code Mode: Keeping Tool Responses Out of Agent Context
Anthropic's code_execution processes data already in context. Custom MCP code mode keeps raw tool responses in a sandbox. 14K tokens vs 500.
11 min
Comparing BM25, TF-IDF, and Hybrid Search for MCP Tool Discovery
Benchmarking BM25, TF-IDF, and hybrid search for MCP tool discovery across 916 tools. The 80/20 TF-IDF/BM25 hybrid hits 21% Top-1 accuracy in under 1ms.
10 min
Indirect Prompt Injection Defense for MCP Tools: A Technical Guide
MCP tools that read emails, CRM records, and tickets are indirect prompt injection vectors. Here's how we built a two-tier defense that scans tool results in ~11ms.
12 min
MCP vs A2A: Architecture, Security, and When to Use Each
MCP vs A2A: what each protocol standardizes, how they differ, their shared security risks including indirect prompt injection, and when to use one, both, or a hybrid architecture.
12 min
MCP vs API: What 200+ Connector Builds Taught Us
MCP wraps APIs, it doesn't replace them. After building 200+ connectors that serve both, here's when each approach wins.
14 min read
JustCall MCP Server FAQ
Does StackOne have a JustCall MCP server?
JustCall MCP server vs direct API integration — what's the difference?
How does JustCall authentication work for AI agents?
origin_owner_id.Are JustCall MCP tools vulnerable to prompt injection?
What is the context bloat of a JustCall agent and how do I avoid it?
Can I limit which actions my JustCall agent can access?
Can I create custom agent actions for my JustCall MCP server?
When should I NOT use a JustCall MCP server?
What AI frameworks and AI clients does the StackOne JustCall MCP server support?
Put your AI agents to work
All the tools you need to build and scale AI agent integrations, with best-in-class connectivity, execution, and security.