# BeliefState Entity Search

> BeliefState Entity Search is a paid API for AI agents from beliefstate.ai, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Search and resolve financial/economic entities (companies, instruments, sectors, themes, etc.) by name or keyword for use in analyst research lookups

## Facts

- Endpoint: POST https://beliefstate.ai/v1/research/search_entities?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/beliefstate-entity-search-88e23c58
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TNKxXdNvZoND7W50ZNiNv

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 beliefstate-entity-search-88e23c58 -d '<json body>'
```

Example prompt: Search BeliefState for a 'company' entity matching 'Nvidia' as of today and return up to 10 results so I can find the right entity ID before pulling analyst research on it.

## When to prefer this

Use this endpoint as the first step in a BeliefState research workflow when you need to resolve a named entity (company, instrument, sector, theme, person, country, commodity, etc.) to a canonical entity ID before fetching analyst theses or research. Prefer this over free-text research queries when the entity is ambiguous or you need to disambiguate between similarly named entities.

## Known failure modes

- Query string too short (minLength 1) or too long (maxLength 80) returns validation error
- Invalid kind enum value causes schema rejection
- Malformed as_of datetime (must be ISO 8601 UTC with Z suffix) causes validation error
- Limit outside range 1–50 returns validation error
- No matching entities found returns empty result set
- Payment failure or insufficient USDC balance blocks the request
- Invalid or expired cursor causes pagination error

## How this service works

The first AI-powered platform for top analyst research. Get theses from top analysts, dated evidence, and available outcomes for your AI.

## Output

A paginated JSON envelope (schema_version '1') containing matched entity records relevant to the search query, along with a generated_at timestamp and an as_of timestamp indicating data currency. The full response schema includes entity details usable in downstream BeliefState research endpoints.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input",
  "output"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "properties": {
      "q": {
       "type": "string",
       "maxLength": 80,
       "minLength": 1
      },
      "kind": {
       "enum": [
        "company",
        "instrument",
        "commodity",
        "macro_variable",
        "industry",
        "sector",
        "theme",
        "country",
        "geography",
        "person",
        "policy",
        "event_series",
        "event_occurrence",
        "currency",
        "index"
       ],
       "type": "string"
      },
      "as_of": {
       "type": "string",
       "format": "date-time",
       "pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d:[0-5]\\d(?:\\.\\d+)?(?:Z))$"
      },
      "limit": {
       "type": "integer",
       "maximum": 50,
       "minimum": 1
      },
      "cursor": {
       "type": "string",
       "maxLength": 2048,
       "minLength": 1
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "type": "string",
     "const": "POST"
    },
    "bodyType": {
     "type": "string",
     "const": "json"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type",
    "example"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "$comment": "Envelope excerpt only. Complete response schema: https://beliefstate.ai/v1/research/search_entities?schema=output",
     "required": [
      "schema_version",
      "generated_at",
      "as_of"
     ],
     "properties": {
      "as_of": {
       "type": "string",
       "format": "date-time"
      },
      "generated_at": {
       "type": "string",
       "format": "date-time"
      },
      "schema_version": {
       "type": "string",
       "const": "1"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "as_of": "2026-10-24T00:00:00.000Z",
  "generated_at": "2026-10-24T00:00:00.000Z",
  "schema_version": "1"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/beliefstate-entity-search-88e23c58/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from beliefstate.ai](https://www.zero.xyz/host/beliefstate.ai/llms.txt)