Glow as an MCP Client

Connect canvas AI Agents to reviewed external MCP servers with scoped tool permissions and human approval gates. Admins register public HTTPS endpoints (Streamable HTTP or SSE) under Connections → Agent tools → Add external connection.

At a glanceVerified in app · Oct 30, 2026

Use it to: Connect canvas AI Agent Steps to external HTTPS MCP servers with Admin-reviewed tool catalogues and per-tool human approval policies
Find it: Workspace Connections → Agent tools → Add external connection, then AI Agent Step → Tools → External tools
Limits: Public HTTPS endpoints only (Streamable HTTP or SSE) · Bearer token or Admin-enabled No authentication · New or changed tools stay withheld until reviewed
Instead: Native App Integration tools in AI Agent → Tools (when the service is already in Glow's built-in app catalogue)

1. Register HTTPS Endpoint2. Approve Tool Catalogue3. Attach & Set Approval Gates

To connect external AI apps (Claude, ChatGPT, Gemini, Cursor, VS Code) to build Automations instead, see Connecting AI Apps & Editors.

The Agent tools tab with Add external connection and the workspace switch for allowing external servers without authentication, shown off. — Manage external MCP servers under Agent tools. This workspace has no external server configured.

Connection and Tool Governance

Admins review external connections and tool catalogues first. Builders then select approved tools and configure approval gates on each AI Agent.

Illustrative Governance Flow

How AI Agents Use External Tools

Configured policy determines whether a tool call needs human approval, including read-only calls. Both routes must pass permission and connection checks before dispatch.

1Agent & Gateway

AI Agent StepMCP Client

Selects a reviewed tool granted to this agent

Glow Tool GatewayPolicy Check

Applies the configured tool approval policy

Inspect

2Decision & Governance

Approval required by policy?

Not RequiredNo Review Gate

Permission Checks, Then Dispatch

Check tool permissions, connection status, and arguments before sending the call.

RequiredAwaiting Review

Authorized Human Review

Pause before dispatch for an authorized reviewer. Approval does not bypass permissions or connection checks.

Approved → Checks → Dispatch Rejected → Not Dispatched

Check & Dispatch

3Dispatch & Results

Dispatch ChecksBoth Routes

Permissions, connection availability and review status, and argument schema must pass.

External MCP ServerPublic HTTPS

Receives tool arguments and returns results to the agent

AI Agent OutputStep Output

Reference output from Step 2 with {{ 2.result }}.

Tool results return to the AI Agent for further reasoning. Its final output is available to downstream Steps.

Choose Between a Native App Tool and an External MCP Server

An AI Agent can call native Glow integrations and external MCP servers:

Built-In Catalog (kind: integration)Native App Integration Tool

Use when the service is in Glow's native catalog (Slack, Gmail, Jira, HubSpot).
Authenticates via workspace app connections under Connections.
Supports per-account default approval (none or require) plus per-action overrides.

Custom HTTPS Endpoint (kind: mcp)External MCP Server Tool

Use for internal services, custom tool servers, or specialized APIs.
Authenticates with a server-level Bearer token or Admin-enabled No authentication.
Tools are discovered dynamically, approved by an Admin, and governed per tool.

1. Select Permitted Tools

Saving a connection tests it automatically and opens Approve current catalogue. You can also open View tools or Review tools from the connection row. Builders then select approved tools under Tools → External tools.

New or changed tools stay withheld until an Admin approves them. Prompt instructions never bypass tool selection. Over MCP, builders can attach reviewed MCP connections and set toolApprovalPolicies via update_workflow (see Configuring glowAgent Parameters).

2. Human-in-the-Loop Review Gates

Enable Require approval by default in the AI Agent’s Tools settings. Set per-tool overrides under Action approval settings. Any action, including read calls, can require human approval. Approval requests can expire, and review never bypasses permissions.

3. Connection Credentials

External connections use a Bearer token or No authentication. Saving No authentication also enables unauthenticated external servers for the workspace. Admins can toggle that policy on the Agent tools tab. Glow sends bearer tokens server-side so credentials never enter prompts. Use a least-privilege token and require approval for tools that modify data.

Verify it works

Run: Attach an MCP server or connected app tool to an AI Agent Step and run a Preview test
You should see: The AI Agent discovers the tool schema and proposes or executes the tool call in the run timeline.