# TruthBear Gauge History Series

> TruthBear Gauge History Series is a paid API for AI agents from api.truthbear.co, paid per call via x402, $0.09/call, status unknown (last checked 2026-09-13).

Returns the full retained time-series of snapshots for a specific signal and entity, including snapshot date, observation time, data age, current value, band, and record hash.

## Facts

- Endpoint: GET https://api.truthbear.co/gauge/history-series
- Price: $0.09/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/truthbear-gauge-history-series-c137ad9e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_T1lza6CNqOF9v74XxAwUe

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 truthbear-gauge-history-series-c137ad9e
```

Example prompt: Pull the full history series for the hydrology.river-level signal on entity 07010000 going back 365 days and give it to me as JSON so I can run base-rate analysis.

## When to prefer this

Use this endpoint when you need the complete retained historical record of a signal for research, actuarial, or base-rate work — not just the current reading or a preview. Prefer this over /gauge/history-preview when you need more than 7 snapshots. Use when you need CSV export for downstream statistical tooling. Do not use if you need a forecast, advice, or calibrated normalized index (use gauge/calibrated for normalization).

## Known failure modes

- 422 no_charge returned when no data exists for the specified signal_id and entity combination — call is not billed
- Invalid signal_id or entity returns an error — check /gauge/coverage for valid identifiers
- Days parameter below 1 or above 1000 may be rejected or clamped
- Unsupported format value (not json or csv) may return an error
- Network timeout on very large day windows approaching the 1000-day cap

## How this service works

[TIME SERIES EXPORT] Full retained series for one signal and entity (?days=, ?format=json or csv): every snapshot up to days (default 400, cap 1000) with snapshot_date, observed_at, data_age_hours, current, band and record_hash. For research, actuarial and base-rate work. Free 7-snapshot shape preview at /gauge/history-preview. Descriptive only, never a forecast or advice. No data -> 422 no_charge, not billed. $0.09 per call.

## Output

Returns a JSON or CSV array of time-ordered snapshots for the requested signal and entity. Each record includes snapshot_date, observed_at, data_age_hours, current (the signal value), band (risk tier), and record_hash (integrity identifier). The lookback window defaults to 400 days and is capped at 1000 days. If no data is available, returns a 422 no_charge error without billing.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "GET"
     ]
    },
    "queryParams": {
     "type": "object",
     "additionalProperties": false,
     "properties": {
      "signal_id": {
       "type": "string",
       "description": "required - line id, e.g. hydrology.river-level (see /gauge/coverage)",
       "examples": [
        "hydrology.river-level"
       ]
      },
      "entity": {
       "type": "string",
       "description": "required - object id within that line, e.g. 07010000 (see /gauge/coverage)",
       "examples": [
        "07010000"
       ]
      },
      "days": {
       "type": "string",
       "description": "optional - lookback window in days; default 400, minimum 1, capped at 1000. Windows are UTC days (snapshot_date), not local days"
      },
      "format": {
       "type": "string",
       "description": "optional - json (default) or csv"
      }
     },
     "required": [
      "signal_id",
      "entity"
     ]
    }
   },
   "required": [
    "type",
    "method",
    "queryParams"
   ]
  },
  "output": {
   "type": "object",
   "properties": {
    "type": {
     "const": "json"
    }
   },
   "required": [
    "type"
   ]
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/truthbear-gauge-history-series-c137ad9e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.truthbear.co](https://www.zero.xyz/host/api.truthbear.co/llms.txt)