MCP
MCP lets AI assistants read and act on work context through tools.
Endpoint and authentication
The hosted MCP endpoint is the server URL for clients that ask for one:
https://mcp.onehorizon.ai/mcpAuthentication uses OAuth 2.0. Public clients use PKCE directly, so most MCP clients do not need a client ID or client secret. The assistant acts with the workspace access of the person who connects it.
Choose MCP for assistants that answer questions, prepare updates, create work, or update work inside the assistant. Choose the REST API or JavaScript SDK for backend services and CI jobs.
What assistants can do
MCP gives assistants three kinds of tools.
| Capability | Examples |
|---|---|
| Read work | Recaps, planned work, completed work, blockers, initiatives, bugs, teams, workspaces, and taxonomy. |
| Create and update work | Initiatives, bugs, feature requests, todos, comments, and task fields the user can access. |
| Prepare updates | Work summaries, standup prep, handoff notes, initiative summaries, and bug triage prep. |
Common requests include:
- "Show my planned work for this week."
- "Give me a team recap for last week."
- "What's blocking the frontend team?"
- "Capture this as completed work."
- "Prepare bug triage notes for the open bugs."
- "Write handoff notes for the tasks I finished today."
For execution work, MCP is usually the context layer. Keep the work item clear with spec-driven development, then move into AI Handoff, Use in Terminal, or Local Workers for implementation.
Client setup
| Client | Setup notes |
|---|---|
| ChatGPT | Requires ChatGPT Plus or higher with Developer Mode enabled. Add a custom app in ChatGPT Apps with the One Horizon MCP endpoint and OAuth authentication. Developer Mode currently works in regular chats, not Project chats or Deep Research. |
| Claude Code | Add the server with claude mcp add --transport http onehorizon https://mcp.onehorizon.ai/mcp, or import it from Claude Desktop with claude mcp add-from-claude-desktop --scope user. Use /mcp inside Claude Code to inspect connected servers. |
| Claude Desktop | Add a remote HTTP MCP server named onehorizon, authenticate through the OAuth prompt, then start a new conversation before using tools. |
| Cursor, Windsurf, JetBrains IDEs, and Codex | Add the MCP server from the tool's MCP settings and authenticate through the browser. If the tool supports project-level MCP config, keep workspace-specific setup in the project config. |
| n8n and automation clients | MCP fits assistant-style tool calls. Webhooks fit workflows that react to workspace events. |
If a client supports both a user-level and project-level MCP configuration, choose user-level for personal work context and project-level when the connection should travel with a repository.
Access rules
MCP runs with the authenticated user's workspace access. Team IDs supplied to create or update tools are validated against teams the user can access.
The assistant cannot see workspaces, teams, documents, or tasks the signed-in user cannot access. It also cannot bypass workspace permissions through a tool call.