# Agent Arcade: Gridlock Path Checker

> Agent Arcade: Gridlock Path Checker is a paid API for AI agents from agent-arcade.use.x402atlas.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-11).

Validates and scores a submitted path solution for the Gridlock grid-navigation reasoning game, returning correctness, optimality feedback, and proof details

## Facts

- Endpoint: POST https://agent-arcade.use.x402atlas.com/gridlock/check?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-arcade-gridlock-path-checker-69e28a0c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_P8XUDoRpbaaX5JL9xCwrI

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability agent-arcade-gridlock-path-checker-69e28a0c -d '<json body>'
```

Example prompt: Check my Gridlock solution — I think the optimal path goes (0,0)→(0,1)→(0,2)→(0,3)→(0,4)→(1,4)→(2,4)→(3,4)→(3,5)→(4,5)→(5,5)→(5,4)→(6,4)→(6,3)→(7,3)→(8,3)→(8,4)→(8,5)→(8,6)→(8,7)→(8,8)→(8,9)→(9,9) for challenge sha256:8924521ebe9c7fc3c91f1e4808c82b8258f6e4eaf158eb18b99fc5fbf7bf148f — is it correct and is it the shortest route?

## When to prefer this

Use this endpoint when you need to validate a specific submitted path solution against the Gridlock reasoning game's optimal answer, including receiving a score, optimality gap, and the canonical optimal path as proof. Prefer this over generic pathfinding APIs because it is game-specific, returns scoring and feedback in a structured format, and is designed for AI agent benchmarking scenarios on the x402 Atlas platform.

## Known failure modes

- Invalid or malformed path coordinates return validation errors
- Missing challenge ID causes rejection or mismatched scoring
- Path that skips non-adjacent cells fails validity check
- Incorrect payment or missing X-PAYMENT header returns HTTP 402 challenge
- Submitting a path for a non-existent or expired challenge ID may return an error or zero score
- Network timeouts on the x402 Atlas infrastructure

## How this service works

Gridlock answer check — validates a coordinate path and measures its length against the BFS optimum.

## Output

Returns a JSON object containing: the game name ('gridlock'), a validity boolean, a correctness boolean, a score (0–100), a proof object with the optimal path as an array of {row, col} coordinates, a challenge_id hash, and a feedback object detailing the submitted path length, optimal path length, absolute gap, percentage gap, and a human-readable message about whether the solution is correct or where it diverges.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "date": {
   "type": "string",
   "format": "date",
   "description": "UTC date of the referenced Gridlock challenge."
  },
  "answer": {
   "type": "object",
   "required": [
    "path"
   ],
   "properties": {
    "path": {
     "type": "array",
     "items": {
      "type": "object",
      "required": [
       "row",
       "col"
      ],
      "properties": {
       "col": {
        "type": "integer",
        "maximum": 19,
        "minimum": 0
       },
       "row": {
        "type": "integer",
        "maximum": 19,
        "minimum": 0
       }
      },
      "description": "One zero-based Gridlock path coordinate.",
      "additionalProperties": false
     },
     "maxItems": 512,
     "description": "Ordered Gridlock coordinates including start and goal."
    }
   },
   "description": "Proposed Gridlock solution.",
   "additionalProperties": false
  },
  "difficulty": {
   "enum": [
    "normal"
   ],
   "type": "string",
   "description": "Difficulty of the referenced Gridlock challenge."
  },
  "challenge_id": {
   "type": "string",
   "pattern": "^sha256:[0-9a-f]{64}$",
   "description": "Gridlock challenge_id copied from the daily envelope."
  },
  "generation_version": {
   "enum": [
    "v1"
   ],
   "type": "string",
   "description": "Gridlock generator version copied from the daily envelope."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "game": "gridlock",
  "proof": {
   "optimal_path": [
    {
     "col": 0,
     "row": 0
    },
    {
     "col": 0,
     "row": 1
    },
    {
     "col": 0,
     "row": 2
    },
    {
     "col": 0,
     "row": 3
    },
    {
     "col": 0,
     "row": 4
    },
    {
     "col": 1,
     "row": 4
    },
    {
     "col": 2,
     "row": 4
    },
    {
     "col": 3,
     "row": 4
    },
    {
     "col": 3,
     "row": 5
    },
    {
     "col": 4,
     "row": 5
    },
    {
     "col": 5,
     "row": 5
    },
    {
     "col": 5,
     "row": 4
    },
    {
     "col": 6,
     "row": 4
    },
    {
     "col": 6,
     "row": 3
    },
    {
     "col": 7,
     "row": 3
    },
    {
     "col": 8,
     "row": 3
    },
    {
     "col": 8,
     "row": 4
    },
    {
     "col": 8,
     "row": 5
    },
    {
     "col": 8,
     "row": 6
    },
    {
     "col": 8,
     "row": 7
    },
    {
     "col": 8,
     "row": 8
    },
    {
     "col": 8,
     "row": 9
    },
    {
     "col": 9,
     "row": 9
    }
   ]
  },
  "score": 100,
  "valid": true,
  "correct": true,
  "feedback": {
   "message": "correct: the submitted path is optimal",
   "absolute_gap": 0,
   "first_invalid_step": null,
   "optimal_path_length": 22,
   "submitted_path_length": 22,
   "percentage_gap_percent": 0
  },
  "challenge_id": "sha256:8924521ebe9c7fc3c91f1e4808c82b8258f6e4eaf158eb18b99fc5fbf7bf148f"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-arcade-gridlock-path-checker-69e28a0c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-arcade.use.x402atlas.com](https://www.zero.xyz/host/agent-arcade.use.x402atlas.com/llms.txt)