Cloudflare Workers Builds

Developer ToolsPublisher: Cloudflare

Route Cloudflare Workers Builds MCP traffic through Formal to control and log what AI agents do in Cloudflare Workers Builds:

Block tools you don’t want agents to call, such as workers_builds_set_active_worker.
Mask sensitive data in tool results, such as secrets and API keys in workers_builds_list_builds responses.
Keep credentials at the Connector, so users and agents never see Cloudflare Workers Builds tokens.
Log every tool call with the user, the MCP client and its parameters.

Cloudflare deprecated this server in favor of the Cloudflare API MCP server.

0. Prepare your Connector

The Connector needs an MCP listener and a hostname with wildcard DNS and TLS. Set them up once by following Deploy the Connector. Every MCP server reuses them.

1. Add Cloudflare Workers Builds MCP server to your Resources

UI
Terraform
Pulumi
API

Open the Admin Catalog and click Add MCP.
Select the Cloudflare Workers Builds template.
Enter a DNS-label Name, such as cloudflare-builds.
Choose the Space containing your Connector, such as default.
Configure upstream authentication as described below, then save.

If no Connector is in the selected Space, the Configuration tab shows MCP clients can’t connect directly yet. The reason reads: No Connector is in this server's Space.

Set space_id to the ID of the Space containing your Connector.

resource "formal_resource" "cloudflare_builds" {
  name                    = "cloudflare-builds"
  technology              = "mcp"
  hostname                = "builds.mcp.cloudflare.com"
  space_id                = "<SPACE_ID>"
  native_users_v3_enabled = true
  port                    = 443
  tags = {
    "mcp-endpoint" = "/mcp"
  }
}

resource "formal_resource_oauth_settings" "cloudflare_builds" {
  resource_id = formal_resource.cloudflare_builds.id
}

Set spaceId to the ID of the Space containing your Connector.

import * as formal from "@formalco/pulumi";

const resource = new formal.Resource("mcp", {
  name: "cloudflare-builds",
  technology: "mcp",
  hostname: "builds.mcp.cloudflare.com",
  port: 443,
  spaceId: "<SPACE_ID>",
  tags: { "mcp-endpoint": "/mcp" },
  nativeUsersV3Enabled: true,
});

new formal.ResourceOauthSettings("mcpOAuth", {
  resourceId: resource.id,
});

Create a Resource with the MCP endpoint and its Space ID.

export FORMAL_API_KEY="<YOUR_API_KEY>"
RESOURCE_RESPONSE=$(curl --fail --silent --show-error \
  --request POST \
  https://api.formal.ai/core.v1.ResourceService/CreateResource \
  --header "x-api-key: ${FORMAL_API_KEY}" \
  --header "Content-Type: application/json" \
  --data-binary @- <<JSON
  {
    "name": "cloudflare-builds",
    "hostname": "builds.mcp.cloudflare.com",
    "port": 443,
    "technology": "mcp",
    "spaceId": "<SPACE_ID>",
    "tags": [
      {
        "key": "mcp-endpoint",
        "value": "/mcp"
      }
    ]
  }
JSON
)
RESOURCE_ID=$(printf '%s' "${RESOURCE_RESPONSE}" | jq -r '.resource.id')
curl --fail --silent --show-error \
  --request POST \
  https://api.formal.ai/core.v1.ResourceService/CreateResourceOAuthSettings \
  --header "x-api-key: ${FORMAL_API_KEY}" \
  --header "Content-Type: application/json" \
  --data-binary @- <<JSON
  {
    "resourceId": "${RESOURCE_ID}"
  }
JSON

2. Setup Authentication

Linked Accounts (Recommended)
Shared Credentials
Pass Through

Each user links their own Cloudflare Workers Builds account once in the Employee Catalog, and the Connector sends that user’s token to Cloudflare Workers Builds.

Linked Accounts selected under How does Formal authenticate to this resource?

Under OAuth app, keep Formal’s App.

Formal’s App (default)

Formal has a registered OAuth app with Cloudflare Workers Builds, so you register nothing. Users see Formal on Cloudflare Workers Builds’s consent screen.

An administrator stores one Cloudflare Workers Builds token in Formal, and the Connector sends it on every user’s requests without showing it to them.

Shared Credentials selected under How does Formal authenticate to this resource?

Cloudflare Workers Builds’s MCP endpoint accepts an API token as a Bearer token. Create one at dash.cloudflare.com/profile/api-tokens. Give the token account read, Workers read, and Workers Builds read access (OAuth scopes account:read, workers:read, workers_builds:read).

Open this server from the Admin Catalog.
Select Configuration, then Authentication.
Choose Shared Credentials, then select Add credential.
Enter the credential, make it the default, and select Save authentication.

See Native Users.For HTTP Bearer authentication, enter the raw token. The Connector adds the Bearer prefix.In the Terraform tab, set native_users_v3_enabled = true on the Resource and upstream_oauth_mode = "none" on its OAuth settings.

variable "mcp_shared_credential" {
  type      = string
  sensitive = true
}

resource "formal_native_user_v3" "mcp_shared_credential" {
  resource_id = formal_resource.cloudflare_builds.id
  label       = "shared-credential"

  http_bearer {
    header = "Authorization"
    token {
      literal_wo         = var.mcp_shared_credential
      literal_wo_version = 1
    }
  }
}

resource "formal_resource_native_user_selection" "mcp_shared_credential" {
  resource_id = formal_resource.cloudflare_builds.id
  cel         = "\"${formal_native_user_v3.mcp_shared_credential.id}\""
}

3. Route Endpoint traffic

Auth is managed at the Connector level when you use Linked Accounts or Shared Credentials, so the Endpoint needs to forward the MCP traffic to it. Laptops and VMs with the Formal Endpoint keep using https://builds.mcp.cloudflare.com/mcp, and a network rule sends that traffic to the Connector.

UI
Terraform
Pulumi
API

Go to Network Rules and create a rule named cloudflare-builds-mcp.
Paste this expression, set the rule to Active, then save:

{
  "condition": {
    "pre_tcp": process.is_agent,
    // Every MCP server added to Formal: process.is_agent && resource.technology == "mcp"
    "pre_tls": process.is_agent && hostname == "builds.mcp.cloudflare.com",
    "post_tls": true
  },
  "outputs": {
    "forward_to_connector": true
  }
}

resource "formal_network_rule" "cloudflare_builds_mcp" {
  name        = "cloudflare-builds-mcp"
  description = "Forward Cloudflare Workers Builds MCP traffic from agents to the Connector"
  status      = "active"

  # Every MCP server added to Formal: set pre_tls to process.is_agent && resource.technology == "mcp"
  cel_expression = <<-EOT
    {
      "condition": {
        "pre_tcp": process.is_agent,
        "pre_tls": process.is_agent && hostname == "builds.mcp.cloudflare.com",
        "post_tls": true
      },
      "outputs": {
        "forward_to_connector": true
      }
    }
  EOT
}

import * as formal from "@formalco/pulumi";

new formal.NetworkRule("cloudflareBuildsMcp", {
  name: "cloudflare-builds-mcp",
  description: "Forward Cloudflare Workers Builds MCP traffic from agents to the Connector",
  status: "active",
  // Every MCP server added to Formal: set pre_tls to process.is_agent && resource.technology == "mcp"
  celExpression: `
    {
      "condition": {
        "pre_tcp": process.is_agent,
        "pre_tls": process.is_agent && hostname == "builds.mcp.cloudflare.com",
        "post_tls": true
      },
      "outputs": {
        "forward_to_connector": true
      }
    }
  `,
});

export FORMAL_API_KEY="<YOUR_API_KEY>"
# Every MCP server added to Formal: set pre_tls to process.is_agent && resource.technology == "mcp"
CEL_EXPRESSION=$(cat <<'CEL'
{
  "condition": {
    "pre_tcp": process.is_agent,
    "pre_tls": process.is_agent && hostname == "builds.mcp.cloudflare.com",
    "post_tls": true
  },
  "outputs": {
    "forward_to_connector": true
  }
}
CEL
)
jq -n --arg cel "${CEL_EXPRESSION}" '{
  name: "cloudflare-builds-mcp",
  description: "Forward Cloudflare Workers Builds MCP traffic from agents to the Connector",
  status: "active",
  celExpression: $cel
}' | curl --fail --silent --show-error \
  --request POST \
  https://api.formal.ai/core.v1.DesktopService/CreateDesktopRoutingRule \
  --header "x-api-key: ${FORMAL_API_KEY}" \
  --header "Content-Type: application/json" \
  --data-binary @-

The rule matches known agents only. See Identity headers.Cloud agents such as Claude, ChatGPT and Cursor Cloud Agents don’t run the Endpoint. Point them at this server’s Connector address, https://cloudflare-builds.<connector-hostname>/mcp. Find it in the Admin Catalog: open Cloudflare Workers Builds, then copy Connector address on the Configuration tab.

4. Create policies

Tools

The Admin Catalog lists these tools for Cloudflare Workers Builds:

Tool	Description
`workers_builds_set_active_worker`	Set the Worker used by later calls.
`workers_builds_list_builds`	List a Worker’s builds.
`workers_builds_get_build`	Get a build’s details.
`workers_builds_get_build_logs`	Get a build’s logs.

5. Check the logs

Open Logs and search for resource.name:cloudflare-builds. Each Cloudflare Workers Builds tool call is one request log with the user, the MCP client and the tool. Open a log to see its tool parameters and the policies it triggered.See Logs for search syntax and filters.

Troubleshooting

The agent relays: Formal has no current cloudflare-builds sign-in for you. Link or re-link your cloudflare-builds account in Formal…Cause: The user never linked Cloudflare Workers Builds, or the token expired and couldn’t be refreshed.Fix: Open the server in the Employee Catalog and link Cloudflare Workers Builds again.

The agent says Cloudflare Workers Builds rejected your credentials

The agent relays: cloudflare-builds rejected your credentials. Link or re-link your cloudflare-builds account in Formal…Cause: Cloudflare Workers Builds no longer accepts the linked token, for example after the user revoked access in Cloudflare Workers Builds.Fix: Link Cloudflare Workers Builds again from the Employee Catalog.With Shared Credentials, the message asks the user to contact an administrator. Replace the token in the server’s Shared Credentials.

Laptop traffic doesn't appear in Logs

Cause: The Endpoint isn’t running, or the network rule doesn’t match the client.Fix: Check the Endpoint is connected. The rule above only matches known agents. Other clients, such as a browser, reach Cloudflare Workers Builds directly unless the rule also matches them. See Network rules.

MCP clients can't connect directly yet

Cause: The Configuration tab lists the reason, most often No Connector is in this server's Space.Fix: Edit the server and choose the Space containing its Connector.

Getting Started

Example Use Cases

AI Governance

Configuring Formal

Integrations

Configuration

0. Prepare your Connector

1. Add Cloudflare Workers Builds MCP server to your Resources

2. Setup Authentication

Formal’s App (default)

3. Route Endpoint traffic

4. Create policies

Tools

5. Check the logs

Troubleshooting

Next Steps

MCP Gateway

All MCP servers

​0. Prepare your Connector

​1. Add Cloudflare Workers Builds MCP server to your Resources

​2. Setup Authentication

​Formal’s App (default)

​3. Route Endpoint traffic

​4. Create policies

​Tools

​5. Check the logs

​Troubleshooting

​Next Steps

MCP Gateway

All MCP servers

0. Prepare your Connector

1. Add Cloudflare Workers Builds MCP server to your Resources

2. Setup Authentication

Formal’s App (default)

3. Route Endpoint traffic

4. Create policies

Tools

5. Check the logs

Troubleshooting

Next Steps