Built for Agents - Interchange API

The Interchange API is built from the ground up for AI agents. Both humans and agents share the same surface: a REST API and a generic MCP wrapper that exposes the entire surface through three tools — no per-domain tool sprawl, no SDK, no glue code.

Why agent-first

Same surface for humans and agents

REST and MCP expose an identical featureset against the same OpenAPI — no parallel “AI surface” to drift out of sync. See Philosophy for the SESOFI pattern (Single Endpoint, Single Object, Full Intent) that keeps composite intents legible.

Generic MCP wrapper

Three tools (health, ask_about_capability, api_call) cover every endpoint. Adding a new REST endpoint instantly makes it agent-callable — no new MCP tool to write, register, or deploy.

Declarative tool surface

A single skill.md URL teaches an agent the entire API. ask_about_capability queries it on demand, so agents discover endpoints instead of memorizing them.

Role-aware

Buyer and storefront roles each get their own skill file and OpenAPI spec, so agents see only the surface relevant to the caller.

Supported AI agents

Claude (Claude.ai Team/Enterprise, Claude Desktop, Claude Code)
ChatGPT (MCP Connectors and Custom GPTs)
Cursor
Custom agents — anything that speaks MCP or HTTP

Per-agent setup details are below; the Quickstart is a one-page index that links here.

Connection Methods

REST API

Standard HTTP REST API for traditional integrations:

Environment	Buyer Base URL	Storefront Base URL
Production	`https://api.interchange.io/api/v2/buyer`	`https://api.interchange.io/api/v2/storefront`

MCP (Model Context Protocol)

For AI agent integrations using JSON-RPC 2.0:

Environment	Buyer MCP Endpoint	Canonical Storefront Agent URL
Production	`https://api.interchange.io/mcp/buyer`	`https://interchange.io`

The REST URLs are pinned to v2 and will keep serving v2 even after a future major version ships. The buyer MCP URL is an unversioned alias that auto-redirects to whatever is currently stable (today: v2). The storefront URL is the canonical agent identity publishers list in adagents.json. See Versioning for when to use each.

Available MCP Tools

Each MCP endpoint exposes three core tools that cover the entire API surface:

Tool	Purpose
`health`	Check API health and verify connectivity
`ask_about_capability`	Query the skill documentation to discover endpoints and their schemas
`api_call`	Make authenticated REST API calls to any endpoint

Workflow: an agent first uses ask_about_capability to learn what endpoints exist, then uses api_call to execute them. Both endpoints also expose a conversational assistant tool when it is enabled for your account:

Tool	Purpose
`ask_murph`	Ask Murph, your AI guide to Interchange, a plain-English question — “how do I…”, “why is my campaign in this state”, “what changed recently” — or file a support report

ask_murph is available once the assistant is enabled for your account. If it is not yet turned on, the call returns a friendly “not enabled” message instead of an answer — contact Scope3 to enable it. Use ask_murph for guidance and support, and the three core tools (api_call et al.) for actual reads and mutations.

Connecting AI Agents

Claude Connector (Claude.ai Team / Enterprise)

This is the recommended way to connect Claude to Scope3. It provides OAuth-based authentication and works across both Claude.ai (browser) and Claude Desktop automatically.

Admin Setup (one-time):

Go to claude.ai → Admin Settings → Integrations → MCP Connectors
Click Add Connector
Enter the MCP endpoint URL: https://api.interchange.io/mcp/buyer
Name it (e.g., “Interchange API”)
Save the connector — it is now available to all members in your organization

User Setup:

Go to claude.ai → Settings → Integrations → MCP Connectors
Find the Scope3 connector and click Connect
Log in with your Scope3 credentials when prompted (OAuth)
Start chatting! Ask Claude: “List my advertisers” or “Create a performance campaign”

Once connected via the connector, it works in both Claude.ai (browser) and Claude Desktop. No separate configuration needed.

Claude Desktop (Personal / Manual Setup)

If you don’t have a Claude Team or Enterprise plan, you can connect Claude Desktop directly via OAuth. Edit your Claude Desktop config file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "scope3-buyer": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://api.interchange.io/mcp/buyer"]
    }
  }
}

Restart Claude Desktop. The first call opens a browser for you to sign in to Interchange — mcp-remote caches the OAuth token afterward. If you need to use an API key instead (CI, headless environments), pass it as a header:

{
  "mcpServers": {
    "scope3-buyer": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://api.interchange.io/mcp/buyer",
        "--header",
        "Authorization: Bearer scope3_your_api_key_here"
      ]
    }
  }
}

Claude Code (CLI)

OAuth (recommended — no key to manage):

claude mcp add --transport http scope3-buyer https://api.interchange.io/mcp/buyer
claude

The first call to the server opens a browser to sign in to Interchange. Claude Code caches the token after that. API key (CI, headless, or if you can’t open a browser): pass the header on registration. Claude Code’s HTTP transport doesn’t read environment variables, so the API key must be set as a header here.

claude mcp add --transport http scope3-buyer https://api.interchange.io/mcp/buyer \
  --header "Authorization: Bearer scope3_your_api_key_here"
claude

Then ask: “Use ask_about_capability to learn how to list advertisers, then use api_call to list them” Once connected, Claude Code can also talk to Murph directly through the same server — no extra setup. Just ask a question in plain English and Claude Code will call the ask_murph tool:

Ask Murph why my campaign is still in PENDING

Ask Murph how to register credentials for a sales agent

Murph keeps its own conversation thread (returned as conversationUid in the tool result); follow-up questions in the same Claude Code session continue that thread. ask_murph is for guidance and support — for actual reads or mutations, Claude Code uses api_call.

ChatGPT

Important: ChatGPT MCP connectors use OAuth authentication only. Custom headers like x-scope3-api-key are not supported. Authentication is handled automatically through the OAuth login flow.

MCP Connector
Custom GPT

Connect ChatGPT to Scope3 via MCP:

Go to ChatGPT → Settings → MCP Connectors
Click Add Connector
Enter MCP Server URL: https://api.interchange.io/mcp/buyer
Select OAuth as the authentication method
Complete the Scope3 login flow when prompted
Once connected, you’ll have access to 3 tools:
- health - Check API status
- ask_about_capability - Learn about available endpoints
- api_call - Make authenticated API calls
Test with: “Use ask_about_capability to learn how to list advertisers”

Create a Custom GPT with OAuth:

Go to ChatGPT → My GPTs → Create a GPT
Go to Configure → Actions → Create new action
Import the OpenAPI spec:
- Click Import from URL
- Enter: https://api.interchange.io/api/v2/buyer/openapi.yaml
Set up OAuth authentication:
- Authentication type: OAuth
- Client ID: (contact Scope3 to register your GPT)
- Authorization URL: https://api.interchange.io/authorize
- Token URL: https://api.interchange.io/auth/token
- Scope: openid profile email
Save and test with: “List all my advertisers”

Cursor

Configure Cursor with the Scope3 MCP server:

Open Cursor Settings → MCP tab
Add a new MCP server:
- Name: scope3
- URL: https://api.interchange.io/mcp/buyer
- Headers: Authorization: Bearer your-api-key
Restart Cursor
In chat, ask: “Use Scope3 tools to list advertisers”

Authentication

Use OAuth for Claude/ChatGPT MCP connectors (handled automatically) or an API key (Authorization: Bearer scope3_...) for CLIs, Cursor, and custom agents. See Authentication for full details.

Notifications

The API surfaces unread notifications inline in ask_about_capability responses, so agents can proactively flag campaign or creative issues to users. See the Notifications guide for setup and the REST endpoints.

Next Steps

Quickstart

Connect Claude, ChatGPT, Cursor, or a custom agent in minutes.

Buyer Onboarding

The end-to-end campaign-launch journey for buyer integrations.

Skill

What skill.md is and how agents use it for capability discovery.

Authentication

API keys, OAuth, and SSO configuration.

​Why agent-first

Same surface for humans and agents

Generic MCP wrapper

Declarative tool surface

Role-aware

​Supported AI agents

​Connection Methods

​REST API

​MCP (Model Context Protocol)

​Available MCP Tools

​Connecting AI Agents

​Claude Connector (Claude.ai Team / Enterprise)

​Claude Desktop (Personal / Manual Setup)

​Claude Code (CLI)

​ChatGPT

​Cursor

​Authentication

​Notifications

​Next Steps

Quickstart

Buyer Onboarding

Skill

Authentication

Why agent-first

Supported AI agents

Connection Methods

REST API

MCP (Model Context Protocol)

Available MCP Tools

Connecting AI Agents

Claude Connector (Claude.ai Team / Enterprise)

Claude Desktop (Personal / Manual Setup)

Claude Code (CLI)

ChatGPT

Cursor

Authentication

Notifications

Next Steps