# Grades & Study Calc – Grade Curve

> Grades & Study Calc – Grade Curve is a paid API for AI agents from grades-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).

Curves a set of test scores using add-points, scale-to-top, or square-root method, returning original and adjusted scores with before/after averages.

## Facts

- Endpoint: GET https://grades-calc.x402tookit.com/grade-curve?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/grades-study-calc-grade-curve-d1ccf49a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_yTvNVQeZklMdLxfYmYrki

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 grades-study-calc-grade-curve-d1ccf49a
```

Example prompt: Can you curve these test scores — 58, 63, 71, 74, 82, 89, 95 — using the scale-to-top method and show me the before and after class averages?

## When to prefer this

Use this endpoint when you need to mathematically curve a batch of raw test scores using one of three standard academic curving methods and want to see both individual adjustments and aggregate statistics (before/after averages). Prefer this over manual calculation when dealing with up to 200 scores at once.

## Known failure modes

- Missing required 'scores' or 'method' query parameter returns an error
- Invalid method string (not 'add', 'scale-to-top', or 'sqrt') returns a validation error
- More than 200 scores provided may be rejected
- Non-numeric or malformed score values cause a parse error
- Payment failure (402) if USDC balance is insufficient

## How this service works

Curve test scores by adding points, scaling so the top score is 100, or the square-root method, with before and after averages.

## Output

Returns a list of each score's original value, curved value, and change; plus the class average and highest score before and after curving, the method used, and whether results were capped at 100.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "scores",
      "method"
     ],
     "properties": {
      "cap": {
       "type": "string",
       "description": "false to allow results above 100 (default true caps at 100)"
      },
      "method": {
       "type": "string",
       "description": "add, scale-to-top or sqrt"
      },
      "points": {
       "type": "number",
       "description": "Points to add for method add (default 5)"
      },
      "scores": {
       "type": "string",
       "description": "Comma-separated scores out of 100 (up to 200)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "capped": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "method": {
       "type": [
        "null",
        "string"
       ]
      },
      "scores": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
         "change": {
          "type": [
           "null",
           "number"
          ]
         },
         "curved": {
          "type": [
           "null",
           "number"
          ]
         },
         "original": {
          "type": [
           "null",
           "number"
          ]
         }
        }
       }
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "disclaimer": {
       "type": [
        "nul
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/grades-study-calc-grade-curve-d1ccf49a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from grades-calc.x402tookit.com](https://www.zero.xyz/host/grades-calc.x402tookit.com/llms.txt)