# Physics Constants Search

> Physics Constants Search is a paid API for AI agents from physics.openverbs.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-14).

Search physical constants by key, symbol, or name substring with ranked results (exact > prefix > substring matches)

## Facts

- Endpoint: POST https://physics.openverbs.com/v1/search
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/physics-constants-search-b386ca26
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_N8AMeCP0L5rqWeK9W0x7e

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 physics-constants-search-b386ca26 -d '<json body>'
```

Example prompt: Search the physics constants database for anything matching 'Planck' and give me up to 10 results.

## When to prefer this

Use this endpoint when you don't know the exact key or symbol for a constant and need fuzzy/partial matching with ranked results. Prefer the lookup endpoint when you have an exact key or symbol. Prefer the list endpoint when you want to browse all constants in a category without a specific query.

## Known failure modes

- Query string empty or exceeds 60 characters — validation error returned
- Limit outside range 1–42 — validation error returned
- No constants match the query — empty results list with total count of 0
- Network timeout or service unavailability — HTTP 5xx error

## How this service works

Search the constants table by key, symbol or name substring. Exact matches rank first, then prefix matches, then substring matches. Returns up to `limit` constants (default 20) plus the total match count.

## Output

A ranked list of matching physical constants (up to the specified limit, default 20), each including key, symbol, name, value, unit, and category, plus a total match count indicating how many constants matched the query overall.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "query"
     ],
     "properties": {
      "limit": {
       "type": "integer",
       "maximum": 42,
       "minimum": 1,
       "description": "Maximum matches to return. Default 20."
      },
      "query": {
       "type": "string",
       "maxLength": 60,
       "minLength": 1,
       "description": "Key, symbol or name fragment."
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/physics-constants-search-b386ca26/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from physics.openverbs.com](https://www.zero.xyz/host/physics.openverbs.com/llms.txt)