kairo-hardening

Active entropy-based request blocking. Place after kairo-membrane to reject high-entropy requests before they reach your handlers.

npm install @thekairojs/kairo @thekairojs/kairo-hardening

import { createApp } from '@thekairojs/kairo'
import { createMembrane } from '@thekairojs/kairo-membrane'
import { createHardening } from '@thekairojs/kairo-hardening'

const app = createApp()
app.use(createMembrane())
app.use(createHardening({ threshold: 0.75 }))

Options

createHardening({
  threshold: 0.75,           // entropy >= this triggers the action [0–1]. Default: 0.75
  action:    'block',        // 'block' (default) or 'log' (pass through but emit event)
  status:    429,            // HTTP status on block. Default: 429
  message:   'Request rejected',
  onExceed:  async (ctx, entropy) => {
    await alertSlack(`entropy spike: ${entropy} on ${ctx.path}`)
  },
})

Modes

| Mode | Behaviour | |------|-----------| | block | Sends HTTP response, stops middleware chain | | log | Emits entropy_spike event, calls onExceed, passes through |

log mode is useful for gradual rollout — observe what would be blocked before enabling block.

Both modes emit an entropy_spike security event on ctx.kairo.events.