{
  "id": "hedged-request-lab",
  "title": "Hedged Request Lab",
  "tagline": "Measure the extra work required to escape a slow read request.",
  "summary": "Help client developers evaluate delayed duplicate requests for safe reads. Send a second attempt only after a configurable delay, accept the first valid response, and record cancellation, late completion and duplicate service work separately. Export a bounded HTTP client and a latency-versus-work report from controlled local endpoints.",
  "level": 4,
  "source": "core",
  "status": "ready",
  "hours": 8,
  "languages": [
    "Go"
  ],
  "author": {
    "name": "AI Engineering from Scratch",
    "github": "rohitg00"
  },
  "youWillBuild": "Hedged-read client, controllable endpoint fixtures and latency/work comparison receipt",
  "prerequisiteProjects": [
    "llm-gateway-with-fallbacks",
    "agent-trace-debugger"
  ],
  "demo": {
    "command": [
      "go",
      "run",
      "."
    ],
    "cwd": "solution"
  },
  "stages": [
    {
      "id": "01-measure-safe-reads",
      "title": "Measure safe-read latency",
      "summary": "Summarize observed samples without inventing a performance guarantee.",
      "hours": 2,
      "language": "go",
      "difficulty": "starter",
      "concepts": [
        "percentiles",
        "safe reads",
        "measurement"
      ],
      "timeout": 120,
      "figure": "pj-hedged-request-lab-1"
    },
    {
      "id": "02-schedule-duplicate",
      "title": "Schedule delayed duplicate attempts",
      "summary": "Launch a second safe read only when the delay expires before a winner.",
      "hours": 2,
      "language": "go",
      "difficulty": "core",
      "concepts": [
        "timers",
        "overlap",
        "deadline"
      ],
      "timeout": 120,
      "figure": "pj-hedged-request-lab-2"
    },
    {
      "id": "03-validate-and-account",
      "title": "Validate winners and account for late work",
      "summary": "A fast error cannot win, and cancellation is an observation rather than a billing guarantee.",
      "hours": 2,
      "language": "go",
      "difficulty": "core",
      "concepts": [
        "valid winner",
        "late results",
        "cancellation"
      ],
      "timeout": 120,
      "figure": "pj-hedged-request-lab-3"
    },
    {
      "id": "04-export-tradeoffs",
      "title": "Export latency and duplicate-work tradeoffs",
      "summary": "Report both faster responses and the extra requests that produced them.",
      "hours": 2,
      "language": "go",
      "difficulty": "core",
      "concepts": [
        "comparison receipt",
        "service work",
        "consumer"
      ],
      "timeout": 120,
      "figure": "pj-hedged-request-lab-4"
    }
  ],
  "demos": [
    {
      "gif": "media/run.gif",
      "poster": "media/run.png",
      "title": "Initialize and grade",
      "caption": "Recorded starter failure followed by every reference stage passing."
    },
    {
      "gif": "media/output.gif",
      "poster": "media/output.png",
      "title": "Inspect actual output",
      "caption": "Recorded local command output. See the README for input and scope."
    }
  ]
}