Live 70 Actions

Ontra MCP Server
for AI Agents

Q: What AI frameworks and AI clients does the StackOne Ontra MCP server support?

The StackOne Ontra MCP server supports both. MCP clients (paste-and-go apps): Claude Desktop, Claude Code, Cursor, VS Code, Goose. Agent frameworks (code SDKs you build with): OpenAI Agents SDK, Anthropic, Vercel AI, Google ADK, CrewAI, Pydantic AI, LangChain, LangGraph, Azure AI Foundry.

Connect your AI agent to StackOne's Ontra MCP server and give it 70 MCP tools out of the box. Auth, tool execution, and security all managed.

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Ontra MCP Server

Built by

StackOne

Coverage

70 Agent Actions

Create, read, update, and delete across Ontra — and extend your agent's capabilities with custom actions.

MCP Actions → Build Actions →

Authentication

Agent Tool Authentication

Per-user OAuth in one call. Your Ontra MCP server gets session-scoped tokens with zero credentials stored on your infra.

Agent Auth →

Security

Agent Protection

Every Ontra 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 Ontra call.

Tools Discovery →

What is the Ontra MCP Server?

A Ontra MCP server lets AI agents read and write Ontra data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Ontra MCP server ships with 70 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 Ontra MCP Tools

Every action from Ontra's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.

Accounts

List Accounts
Retrieves a paginated list of accounts.
Get Account
Retrieves a single account by id.

Contractual Relationships

Create Contractual Relationship
Creates a new contractual relationship.
List Contractual Relationships
Retrieves a paginated list of all contractual relationships.
Get Contractual Relationship
Retrieves a single contractual relationship by id.
Update Contractual Relationship
Updates an contractual relationship.
Delete Contractual Relationship
Deletes a single contractual relationships by id.

Entitys

Create Entity
Creates a new entity, e.g. a Fund in Insight.
Get Entity
Retrieves a single entity by id.
Update Entity
Updates an entity.
Delete Entity
Deletes a single entity by id.

Entity Registrations

Create Entity Registration
Creates a new Entity Registration.
List Entity Registrations
Retrieves a paginated list of entity registrations.
Get Entity Registration
Retrieves a single entity registration by id.
Update Entity Registration
Updates an entity registration.
Delete Entity Registration
Deletes a single entity registration by id.

External Entitys

Create External Entity
Creates a new external entity, e.g. a Legal Entity Name in Insight.
Get External Entity
Retrieves a single external entity by id.
Update External Entity
Updates an external entity.
Delete External Entity
Deletes a single external entity by id.

Ownership Relationships

Create Ownership Relationship
Creates a new ownership relationship.
List Ownership Relationships
Retrieves a paginated list of all ownership relationships.
Get Ownership Relationship
Retrieves a single ownership relationship by id.
Update Ownership Relationship
Updates an ownership relationship.
Delete Ownership Relationship
Deletes a single ownership relationships by id.

Persons

Create Person
Creates a new person.
Get Person
Retrieves a single person entity by id.
Update Person
Updates a person.
Delete Person
Deletes a single person by id.

Tax Identifiers

Create Tax Identifier
Creates a new Tax Identifier.
List Tax Identifiers
Retrieves a paginated list of tax identifiers.
Get Tax Identifier
Retrieves a single tax identifier by id.
Update Tax Identifier
Updates a tax identifier.
Delete Tax Identifier
Deletes a single tax identifier by id.

Other (32)

Get Contractual Relationship Counterparty
Retrieves the contractual relationship's counterparty.
Get Contractual Relationship Party
Retrieves the contractual relationship's party.
Get Contractual Relationship Relationship Type
Retrieves the contractual relationship's relationship type.
List Contractual Relationship Types
Retrieves a paginated list of all contractual relationship types.
List Currencies
Retrieves a paginated list of currencies.
List Entities
Retrieves a paginated list of entities, e.g. a list of Funds in Insight.
Get Entity Currency
Retrieves the entity's default currency.
Get Entity Entity Type
Retrieves the entity's type, e.g. Limited Liability Company.
List Entity Holding Relationships
Retrieves the entity's holdings.
Get Entity Jurisdiction
Retrieves the entity's jurisdiction.
List Entity Owner Relationships
Retrieves the entity's owners.
List Purposes For Entity
Retrieves the entity's purposes, e.g. General Partner, Co-investment Vehicle, etc.
List Registrations For Entity
Retrieves the entity's registrations.
List Entity Tax Identifiers
Retrieves the entity's tax identifiers.
Get Entity Tax Treatment
Retrieves the entity's tax treatment.
List Entity Types
Retrieves a paginated list of entity types.
List Entity Purposes
Retrieves a paginated list of entity purposes.
List External Entities
Retrieves a paginated list of external entities, e.g. a list of Legal Entity Names in Insight.
List External Entity Holding Relationships
Retrieves the external entity's holdings.
Get External Entity Jurisdiction
Retrieves the external entity's jurisdiction.
List Jurisdictions
Retrieves a paginated list of jurisdictions.
Get Ownership Relationship Currency
Retrieves the ownership relationship's currency.
Get Ownership Relationship Holding
Retrieves the ownership relationship's holding.
Get Ownership Relationship Owner
Retrieves the ownership relationship's owner.
Get Ownership Relationship Relationship Type
Retrieves the ownership relationship's relationship type.
List Ownership Relationship Types
Retrieves a paginated list of all ownership relationship types.
List People
Retrieves a paginated list of person entities.
List Person Holding Relationships
Retrieves the person's holdings.
List Registered Agents
Retrieves a paginated list of registered agents.
List Registration Authorities
Retrieves a paginated list of registration authorities.
List Tax Identifier Types
Retrieves a paginated list of tax identifier types.
List Tax Treatments
Retrieves a paginated list of tax treatments.

Set Up Your Ontra MCP Server in Minutes

One endpoint. Any framework. Your agent is talking to Ontra in under 10 lines of code.

MCP Clients

Agent Frameworks

Claude Desktop-

JSON

Claude Desktop Docs

{
  "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>"
      ]
    }
  }
}

Ontra Resources

When Your AI Agent Needs Contractors, Not Apprentices: Building Async Subagents

Explores the difference between using apprentice-like tools versus contractor-style independent agents for handling specialized tasks.

8 min

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 Hundreds of Connector Builds Taught Us

MCP wraps APIs, it doesn't replace them. After building hundreds of connectors that serve both, here's when each approach wins.

14 min read

Ontra MCP Server FAQ

Does StackOne have a Ontra MCP server?

Yes. StackOne offers a hosted Ontra MCP server with 70 pre-built actions, and every action is tested and QA'd by StackOne. Connect it to Claude, Cursor, and any other MCP client, or to any agent framework through the AI Action SDK. It ships with managed agent authentication, prompt injection defense, and tool discovery with server-side execution that preserve your agent's context window and keep reasoning performance.

Ontra MCP server vs direct API integration — what's the difference?

A Ontra MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Ontra. A Ontra MCP server is for AI agents — MCP clients like Claude and Cursor, plus framework agents built with OpenAI, LangChain, or Vercel AI — discovering and calling Ontra at runtime. StackOne provides both.

How does Ontra authentication work for AI agents?

Ontra authentication for AI agents works through a StackOne Connect Session. Create one via the dashboard or the SDK — you get an auth link and ready-to-paste config for Claude Desktop, Cursor, and other MCP clients. Your user authenticates their own Ontra account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via origin_owner_id.

Are Ontra MCP tools vulnerable to prompt injection?

Yes — Ontra MCP tools can be vulnerable to indirect prompt injection. Any tool that reads user-written content — documents, messages, tickets, records, or free-text fields — is a potential vector. StackOne Defender scans every tool response before it enters the agent's context — regex patterns in ~1ms, then a MiniLM classifier in ~4ms. 88.7% accuracy, CPU-only.

What is the context bloat of a Ontra agent and how do I avoid it?

Context bloat happens when Ontra tool schemas and API responses eat your Ontra agent's memory, preventing it from reasoning effectively. A single Ontra query can return a massive JSON response, and connecting multiple tools compounds the problem. Tools Discovery and Code Mode reduce context bloat — loading only relevant tools per query and keeping raw responses out of the agent's context.

Can I limit which actions my Ontra agent can access?

Yes — you can limit which actions your Ontra agent can access directly from the StackOne dashboard. Toggle actions on or off, or restrict them to specific accounts, with no code changes to your agent. Session tokens can be scoped to exact actions so if one leaks, exposure stays contained.

Can I create custom agent actions for my Ontra MCP server?

Yes — you can create custom agent actions for your Ontra MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Ontra's API, generate production-ready connector YAML, test against the live API, and validate before you ship.

When should I NOT use a Ontra MCP server?

Skip a Ontra MCP server if your integration is purely software-to-software — direct Ontra API integration is simpler when no AI agent is involved. For deterministic, compliance-critical operations (financial transactions, regulatory reporting), direct API gives you predictable behavior without agent-driven decision-making. MCP shines when AI agents need to dynamically discover and call Ontra actions at runtime.

What AI frameworks and AI clients does the StackOne Ontra MCP server support?

The StackOne Ontra MCP server supports both. MCP clients (paste-and-go apps): Claude Desktop, Claude Code, Cursor, VS Code, Goose. Agent frameworks (code SDKs you build with): OpenAI Agents SDK, Anthropic, Vercel AI, Google ADK, CrewAI, Pydantic AI, LangChain, LangGraph, Azure AI Foundry.

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.

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Ontra MCP Serverfor AI Agents