# TruthBear Gauge Ruler – Official Band & Threshold Ladder > TruthBear Gauge Ruler – Official Band & Threshold Ladder is a paid API for AI agents from api.truthbear.co, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15). Returns the official regulatory band/threshold ladder, classification, and distance-to-action for a gauge line, or a free 422 if no official ruler exists for that line. ## Facts - Endpoint: GET https://api.truthbear.co/gauge/ruler - Price: $0.005/call - Payment: x402 - Status: unknown - Last checked: 2026-09-15 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/truthbear-gauge-ruler-official-band-threshold-ladder-620a04c6 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_v2MElGNBUTm6ILGdJckmn 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-ruler-official-band-threshold-ladder-620a04c6 ``` Example prompt: Can you pull the official regulatory ruler for the USGS gauge line on the Colorado River near Austin — I need to see the band thresholds, what classification it's currently in, and how far it is from the next action threshold? ## When to prefer this Choose this endpoint when you need the authoritative, source-agency-published threshold ladder and classification for a specific gauge line — particularly for regulatory compliance, environmental monitoring, or grid reliability contexts. It is uniquely safe to call speculatively because lines without an official ruler return a free 422 rather than a billable null response. Prefer it over generic data feeds when you need structured band tiers, distance-to-action, and a verifiable record_hash for audit purposes. ## Known failure modes - HTTP 422 with no_charge:true and reason:'no-ruler-for-this-line' when the requested gauge line has no official agency-published ruler (pure market quotes); caller is not billed - Invalid or missing gauge line identifier returns an error - Source agency data temporarily unavailable may cause upstream fetch failure - Malformed request parameters return a client error ## How this service works Add-on, the official ruler: the band and threshold ladder published by the source agency, its classification, and distance-to-action. NOT every line has an official ruler - pure market quotes do not. When it does not, you get 422 with no_charge:true and reason:no-ruler-for-this-line and you are NOT billed. Never a bag of nulls you paid for. Every record carries an offline-recomputable record_hash. $0.0050 per call. ## Output A structured record containing the source-agency-published band ladder (ordered threshold tiers), the current classification of the gauge line within that ladder, and a numeric distance-to-action value. Every response includes an offline-recomputable record_hash for integrity verification. If no official ruler exists for the requested line, the endpoint returns HTTP 422 with no_charge:true and reason:'no-ruler-for-this-line' — no billing occurs. ## Request schema (JSON Schema) ```json { "$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 - signal id (genus.species); free list at GET /gauge/catalog (paged; ?all=1 for every line)", "examples": [ "hydrology.river-level" ] }, "entity": { "type": "string", "description": "required - monitored object id, paired with signal_id; free list at GET /gauge/catalog?signal_id= -> signals[0].entities[]", "examples": [ "07010000" ] } }, "required": [ "signal_id", "entity" ] } }, "required": [ "type", "method", "queryParams" ] }, "output": { "type": "object", "properties": { "type": { "const": "json" }, "example": {} }, "required": [ "type" ] } } } ``` ## Response schema (JSON Schema) ```json { "type": "json", "example": { "dim": "ruler", "grade": "screening-level, not decision-grade", "ruler": { "band": "below_action", "unit": "ft", "scale": "flood_stage", "metric": "gauge_height_ft", "source": "NOAA NWS/NWPS", "standard": "NWS flood category thresholds (official; not judged by this API)", "thresholds": { "major": 65, "minor": 52, "action": 40, "moderate": 56 }, "official_category": "no_flooding", "distance_to_action": 9.31 }, "scope": { "full": "https://api.truthbear.co/scope/v1", "verifiability": "via-endpoint", "monitoring_not_forecast": true, "intelligence_not_command": true }, "entity": "03255000", "nature": "This API supplies data organisation and trend description only. It is not a recommendation to act; the decision is yours. Purely descriptive - no judgement, no prediction.Official source plus record_hash; verify with the free /gauge/verify.", "signal_id": "hydrology.river-level", "provenance": { "freshness": "fresh", "age_hours_now": 23, "freshness_basis": "cadence=daily; fresh<=24h; recent<=192h; dead_source>1440h; age_basis=request-time(now minus observed_at)" }, "source_ref": "https://waterdata.usgs.gov/monitoring-location/03255000/", "entity_name": "Ohio River at Cincinnati, OH", "observed_at": "2026-08-25T04:00:00.000Z", "record_hash": "sha256:5969b8a147f438254edadf246ed1d7801a77c29babb5d725e17870320d620dd7", "record_hash_verifiable": { "mode": "via-endpoint", "note": "This response is a projected delivery (some core fields are omitted to control size). Cross-check record_hash with the free /gauge/verify, or buy /gauge to get the complete core for offline recomputation." } } } ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/truthbear-gauge-ruler-official-band-threshold-ladder-620a04c6/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)