Powers and MCP

Kiro Web supports two ways to extend the agent with additional tools and context: Powers and MCP servers.

For general MCP configuration and concepts that apply across all Kiro surfaces, see MCP. For general Powers documentation, see Powers.

Powers are a set of integrations included with Kiro Web that add specialized tools and context to the agent. You can configure which Powers are enabled for your sessions. To manage Powers, go to Settings, select the Agent tab, and click Manage powers under Sandbox.

MCP servers give you full control over custom tool integrations using the Model Context Protocol. You configure MCP servers manually and they are loaded into the sandbox at the start of each task.

MCP servers

Security warning

MCP stdio servers execute arbitrary commands inside your environment with the same privileges and access as the agent itself. This includes access to your source code, environment variables, secrets, and any credentials available in the session.

Before adding an MCP server, understand that:

The command and args you configure run as a process in your environment — treat them with the same caution as any executable you install
MCP servers have full access to your workspace filesystem, including source code and configuration files
MCP servers can read environment variables and secrets configured for your session
MCP servers run outside the agent's tool-execution sandbox — they are not subject to the same restrictions as agent tool calls
A compromised or malicious MCP server can exfiltrate code, credentials, and data without any additional user confirmation

Only install MCP servers from sources you trust and have reviewed. You are responsible for evaluating the security of any MCP server you configure. Kiro does not vet, sandbox, or restrict the behavior of third-party MCP servers. For more guidance, see MCP security best practices.

Configuration

To add an MCP server:

Go to Settings and select the Agent tab
Under MCP server settings, click Add server
Enter the server name, type (HTTP or local), and command or URL

MCP servers are loaded when the sandbox starts and remain available throughout task execution.

Example configuration

json

{
  "mcpServers": {
    "aws-knowledge-mcp-server": {
      "command": "uvx",
      "args": [
        "fastmcp",
        "run",
        "https://knowledge-mcp.global.api.aws"
      ],
      "env": {}
    }
  }
}

Supported servers

Only local MCP servers are currently supported. Remote MCP servers are not available at this time.

Using environment variables and secrets

You can reference environment variables and secrets in your MCP configuration to securely pass credentials and configuration values to MCP servers.

Use the ${key_name} syntax to reference the key names of your environment variables and secrets in the server configuration:

json

{
  "mcpServers": {
    "server-name": {
      "command": "executable",
      "args": ["arg1", "arg2"],
      "env": {
        "ENV_VAR_KEY": "${my_env_var_key}",
        "SECRET_KEY": "${my_secret_key}"
      }
    }
  }
}

Both environment variables and secrets use the same syntax. The values are resolved when the sandbox starts.

Power authentication (OAuth)

Some Powers connect to third-party services — such as Figma, Stripe, or Supabase — that require you to grant access through an OAuth authorization flow. You complete this once when you install the Power, and the agent uses the connection for all future tasks without prompting you again.

Which Powers require authorization

When you install a Power that needs OAuth, an Authorize button appears next to it in the Powers list. Powers that don't require authorization are ready to use immediately after installation.

Authorizing a Power

Go to Settings and select the Agent tab
Under Sandbox, choose Manage Powers
Find the Power you want to connect and choose Authorize
A new browser tab opens showing the service's consent screen
Review the requested permissions and approve access
You're redirected back to Kiro Web — the Power now shows as connected

After authorization, the agent can use the Power's MCP server in any task. You don't need to re-authorize unless you disconnect or the service revokes access.

Disconnecting a Power

If you no longer want a Power to access a third-party service on your behalf:

Go to Manage Powers in your Agent settings
Find the Power and choose Disconnect

Disconnecting immediately revokes the stored credentials. The Power remains installed but its tools that require the connection will stop working until you authorize again.

Security

Tokens are encrypted at rest and never exposed to the sandbox or the agent
Access is scoped to the permissions you approved on the consent screen
You can disconnect a Power at any time to immediately revoke access

Page updated: August 4, 2026

Environment variables

Environment configuration

{ "mcpServers": { "aws-knowledge-mcp-server": { "command": "uvx", "args": [ "fastmcp", "run", "https://knowledge-mcp.global.api.aws" ], "env": {} } } }

{ "mcpServers": { "server-name": { "command": "executable", "args": ["arg1", "arg2"], "env": { "ENV_VAR_KEY": "${my_env_var_key}", "SECRET_KEY": "${my_secret_key}" } } } }