# Lilambd Constants Search

> Lilambd Constants Search is a paid API for AI agents from api.lilambd.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-11-02).

Searches and retrieves a paginated list of named constants (physical, mathematical, or otherwise) from the Lilambd crossing dataset

## Facts

- Endpoint: GET https://api.lilambd.com/units/constants?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/lilambd-constants-search-7ce513d5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3c59zvusvMyYHOZQOffYJ

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 lilambd-constants-search-7ce513d5
```

Example prompt: Search the Lilambd constants dataset for 'planck' and return up to 10 results so I can see what physical constants are available.

## When to prefer this

Use this endpoint when you need to look up named constants — physical, mathematical, or otherwise — from the Lilambd crossing dataset, especially when you want searchable, paginated, attributed reference data. Prefer this over general web search when you want structured, machine-readable constant values with source attribution in a single API call.

## Known failure modes

- Empty data array returned when search query matches no constants
- No results if 'q' parameter uses an unrecognized term or spelling
- Limit parameter out of range (must be 1-200) may cause an error or default behavior
- Payment failure (402) if USDC payment is not provided or insufficient
- Offset beyond total record count returns empty data array

## How this service works

A crossing for play, feeling, language, science and computation — creating states that do not have names yet.

## Output

Returns a JSON object containing a 'data' array of matching constant records, a 'count' integer indicating how many records were returned, and an 'attribution' string crediting the source license. The data array may be empty if no matches are found.

## 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",
    "queryParams"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "q": {
       "type": "string",
       "description": "Text to search"
      },
      "limit": {
       "type": "string",
       "description": "Max rows (1-200, default 50)"
      },
      "offset": {
       "type": "string",
       "description": "Rows to skip"
      }
     },
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": [],
  "count": 0,
  "attribution": "source licence line"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/lilambd-constants-search-7ce513d5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.lilambd.com](https://www.zero.xyz/host/api.lilambd.com/llms.txt)