Module: AgentHarness::Providers::McpConfigFileSupport

Included in:
Anthropic, Codex
Defined in:
lib/agent_harness/providers/mcp_config_file_support.rb

Overview

Shared concern for writing and cleaning up MCP configuration tempfiles.

Include this module in any provider that needs to write MCP config files for CLI processes. The including class must define an mcp_provider_key method that returns the symbol passed to McpConfigTranslator.for_provider.

Instance Method Summary collapse

Instance Method Details

#cleanup_mcp_tempfiles! ⇒ Object 



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# File 'lib/agent_harness/providers/mcp_config_file_support.rb', line 54

def cleanup_mcp_tempfiles!
  if @mcp_config_tempfiles
    @mcp_config_tempfiles.each do |file|
      file.close unless file.closed?
      file.unlink
    rescue
      nil
    end
    @mcp_config_tempfiles = nil
  end

  if @mcp_docker_config_paths
    @mcp_docker_config_paths.each do |path|
      @executor.execute(["rm", "-f", path], timeout: 5)
    rescue
      nil
    end
    @mcp_docker_config_paths = nil
  end
end

#write_mcp_config_file(mcp_servers, working_dir: nil) ⇒ Object 



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# File 'lib/agent_harness/providers/mcp_config_file_support.rb', line 11

def write_mcp_config_file(mcp_servers, working_dir: nil)
  require "tempfile"
  require "tmpdir"
  require "securerandom"

  config = McpConfigTranslator.for_provider(mcp_provider_key, mcp_servers)
  config_json = JSON.generate(config)

  if @executor.is_a?(DockerCommandExecutor)
    # When running inside a Docker container, write the config file
    # inside the container so the CLI process can read it.
    # Track the path so cleanup_mcp_tempfiles! can remove it after execution.
    container_path = "/tmp/agent_harness_mcp_#{SecureRandom.hex(8)}.json"
    result = @executor.execute(
      ["sh", "-c", "cat > #{container_path}"],
      stdin_data: config_json,
      timeout: 5
    )
    unless result.success?
      raise McpConfigurationError,
        "Failed to write MCP config inside container: #{result.stderr}"
    end

    @mcp_docker_config_paths ||= []
    @mcp_docker_config_paths << container_path

    container_path
  else
    dir = working_dir || Dir.tmpdir
    file = Tempfile.new(["agent_harness_mcp_", ".json"], dir)
    file.write(config_json)
    file.close

    # Hold a reference so the Tempfile is not garbage-collected (and
    # therefore deleted) before the CLI process reads it.
    # Cleaned up by cleanup_mcp_tempfiles! after execution.
    @mcp_config_tempfiles ||= []
    @mcp_config_tempfiles << file

    file.path
  end
end