Connect
Optimize
Secure
Expensify MCP Server
for AI Agents
Production-ready Expensify MCP server with extensible actions — plus built-in authentication, security, and optimized execution.
Expensify MCP Server
Built by 
StackOne
StackOne 
Coverage
15 Agent Actions
Create, read, update, and delete across Expensify — and extend your agent's capabilities with custom actions.
Authentication
Agent Tool Authentication
Per-user OAuth in one call. Your Expensify MCP server gets session-scoped tokens with zero credentials stored on your infra.
Agent Auth →
Security
Agent Protection
Every Expensify 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 Expensify call.
Tools Discovery →What is the Expensify MCP Server?
A Expensify MCP server lets AI agents read and write Expensify data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Expensify MCP server ships with pre-built actions, fully extensible via the Connector Builder — plus managed authentication, prompt injection defense, and optimized agent context. Connect it from MCP clients like Claude Desktop, Cursor, and VS Code, or from agent frameworks like OpenAI Agents SDK, LangChain, and Vercel AI SDK.
All Expensify MCP Tools and Actions
Every action from Expensify's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.
Policies
- List Policies
Retrieve all Expensify policies (workspaces) accessible to the authenticated user, including policy details, roles, and configuration settings
Policys
- Create Policy
Provision a new Expensify expense policy (workspace) with specified name and plan type for organizing expense management workflows
- Get Policy
Retrieve comprehensive policy configuration including expense categories, tags, custom report fields, tax rates, and employee roster with approval hierarchies
Policy Categorys
- Update Policy Category
Add or update individual expense category on a policy with merge action to preserve existing categories and enable granular category management
Policy Tags
- Update Policy Tag
Add or update individual tag within a specific tag level on a policy for multi-dimensional expense classification and reporting
Reports
- Create Report
Programmatically create expense reports with initial expense transactions in user accounts for automated expense submission and approval workflows
- Export Reports
Generate CSV export of approved expense reports with transaction details for accounting integration, audit compliance, and financial reporting workflows
- Download Report
Retrieve CSV file content for previously generated expense report or reconciliation exports to complete data extraction workflows
Report Status
- Update Report Status
Update expense report status to mark approved reports as reimbursed for automated reimbursement workflow completion and accounting reconciliation
Expenses
- Create Expense
Programmatically create individual expense transactions in user accounts for automated expense importing from external systems or receipt processing services
Expense Rules
- Create Expense Rule
Automate expense classification by creating rules that automatically apply tags to employee expenses based on policy configuration and business logic
Card Reconciliations
- Export Card Reconciliation
Generate comprehensive corporate card reconciliation reports for specified date ranges to compare card transactions with expense reports for accounting closure
Employees
- Update Employee
Provision or update employee records in Expensify policy with approval hierarchy and external system identifier mapping via Advanced Employee Updater API
Domain Cards
- List Domain Cards
Retrieve comprehensive inventory of corporate cards configured at domain level with transaction import status and cardholder assignment details
Tag Approvers
- Update Tag Approver
Configure tag-based approval routing to automatically route expenses with specific tags to designated approvers for department or project-based workflows
Set Up Your Expensify MCP Server in Minutes
One endpoint. Any framework. Your agent is talking to Expensify in under 10 lines of code.
MCP Clients
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>"
]
}
}
}More Accounting MCP Servers
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Expensify MCP Server 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
Expensify MCP Server FAQ
Expensify MCP server vs direct API integration — what's the difference?
A Expensify MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Expensify. A Expensify 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 Expensify at runtime. StackOne provides both.
How does Expensify authentication work for AI agents?
Expensify 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 Expensify account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via
origin_owner_id.Are Expensify MCP tools vulnerable to prompt injection?
Yes — Expensify 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 Expensify agent and how do I avoid it?
Context bloat happens when Expensify tool schemas and API responses eat your Expensify agent's memory, preventing it from reasoning effectively. A single Expensify 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 Expensify agent can access?
Yes — you can limit which actions your Expensify 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 Expensify MCP server?
Yes — you can create custom agent actions for your Expensify MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Expensify's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a Expensify MCP server?
Skip a Expensify MCP server if your integration is purely software-to-software — direct Expensify 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 Expensify actions at runtime.
What AI frameworks and AI clients does the StackOne Expensify MCP server support?
The StackOne Expensify 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.