return {
  name: 'evolution-probe',
  inject: ['tools'],
  apply(ctx) {
    harness.registerTool(ctx, harness.defineTool({
      name: 'evolution_probe',
      description: 'Return the deterministic evolution smoke-test value.',
      parameters: {},
      output: {
        schema: { type: 'array', items: { type: 'json' } },
        render(_args, value) { return value },
      },
      async execute() {
        return [{ type: 'text', text: 'EVOLUTION_OK' }]
      },
    }))
  },
}