{
  "id": "tiny-coding-agent",
  "title": "Tiny Coding Agent",
  "level": 1,
  "levelName": "Starter",
  "tagline": "Build a bounded coding loop that applies exact patches to a disposable workspace and runs its real tests through an allowlisted tool contract.",
  "summary": "Build a bounded coding loop that applies exact patches to a disposable workspace and runs its real tests through an allowlisted tool contract.",
  "youWillBuild": "A repair agent that exposes the patch/test evidence trail and refuses unsupported success claims.",
  "usefulFor": [
    "A repair agent that exposes the patch/test evidence trail and refuses unsupported success claims.",
    "The CLI copies a trusted Python workspace to a new destination, then runs its tests as local code."
  ],
  "hours": 8,
  "languages": [
    "Python"
  ],
  "languageWhy": {
    "Python": "The standard library makes parsing, scoring, and failure handling visible without hiding the mechanism behind a framework."
  },
  "status": "ready",
  "source": "core",
  "author": {
    "name": "AI Engineering from Scratch",
    "github": "rohitg00"
  },
  "skills": [
    "Confine file tools to a workspace",
    "Apply exact patches with preconditions",
    "Run real tests through one allowed command",
    "Stop the coding loop on evidence or budget"
  ],
  "prerequisites": [
    {
      "title": "The agent loop",
      "path": "phases/14-agent-engineering/01-the-agent-loop"
    },
    {
      "title": "Data management",
      "path": "phases/00-setup-and-tooling/09-data-management"
    }
  ],
  "figures": true,
  "overviewFigure": "pj-tiny-coding-agent-1",
  "demo": {
    "command": [
      "python3",
      "demo.py"
    ],
    "cwd": "solution"
  },
  "stages": [
    {
      "id": "01-confine-paths",
      "title": "Confine file tools to a workspace",
      "summary": "Resolve existing relative file paths under a workspace and reject traversal, absolute paths, symlink escapes, and nonfiles.",
      "hours": 2,
      "difficulty": "starter",
      "language": "python",
      "languageWhy": "Use explicit data structures and deterministic standard-library operations.",
      "concepts": [
        "path containment",
        "tool boundaries"
      ],
      "figure": "pj-tiny-coding-agent-1"
    },
    {
      "id": "02-apply-exact-patches",
      "title": "Apply exact patches with preconditions",
      "summary": "Replace one exact occurrence and preserve the file on missing or ambiguous matches.",
      "hours": 2,
      "difficulty": "core",
      "language": "python",
      "languageWhy": "Use explicit data structures and deterministic standard-library operations.",
      "concepts": [
        "patch preconditions",
        "atomic writes"
      ],
      "figure": "pj-tiny-coding-agent-2"
    },
    {
      "id": "03-run-real-tests",
      "title": "Run real tests through one allowed command",
      "summary": "Run unittest discovery in the workspace and report passed, tests, output, and a terminal state.",
      "hours": 2,
      "difficulty": "core",
      "language": "python",
      "languageWhy": "Use explicit data structures and deterministic standard-library operations.",
      "concepts": [
        "subprocess",
        "timeouts",
        "test evidence"
      ],
      "figure": "pj-tiny-coding-agent-3"
    },
    {
      "id": "04-bound-the-loop",
      "title": "Stop the coding loop on evidence or budget",
      "summary": "Consume patch and test actions, record results, and return completed, failed, or budget_exhausted.",
      "hours": 2,
      "difficulty": "stretch",
      "language": "python",
      "languageWhy": "Use explicit data structures and deterministic standard-library operations.",
      "concepts": [
        "agent loop",
        "allowlisted tools",
        "terminal states"
      ],
      "figure": "pj-tiny-coding-agent-4"
    }
  ],
  "demos": [
    {
      "gif": "media/run.gif",
      "poster": "media/run.png",
      "title": "Initialize and grade",
      "caption": "Recorded starter failure followed by all reference-solution stages passing. Reference passes do not earn learner certificates."
    },
    {
      "gif": "media/output.gif",
      "poster": "media/output.png",
      "title": "Inspect the output",
      "caption": "Actual output from the local deterministic demo command. See the README for fixture and live-adapter limits."
    }
  ]
}