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  1. Docs
  2. Web
  3. Sandbox
  4. MCP

Powers and MCP


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

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:

  1. Go to Settings and select the Agent tab
  2. Under MCP server settings, click Add server
  3. 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.

Page updated: May 1, 2026
Environment Variables
Environment Configuration