Truth Bear
Add-on, calibrated units: normalized_index and pct_to_action so readings compare across stations. When the line has no calibration basis you get 422 with no_charge:true and reason:no-calibrated-for-this-line, and are NOT billed. Every record carries an offline-recomputable record_hash. $0.0050 per call.
The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Live 402 challenge
Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.
{
"hint": {
"miss": "missing_parameter",
"usage": "/gauge/calibrated?signal_id=<value>&entity=<value>",
"preview": "/gauge/sample",
"missing_params": [
"signal_id",
"entity"
],
"example_request": "/gauge/calibrated?signal_id=hydrology.river-level&entity=07010000&format=thin"
},
"error": "Missing required query parameter(s): signal_id, entity. A request you can run right now: GET /gauge/calibrated?signal_id=hydrology.river-level&entity=07010000&format=thin\nX-PAYMENT header is required",
"rails": {
"available": [
"base",
"solana"
],
"advertised": [
"base"
],
"optin_hint": "Send \"X-Payment-Network: solana\" (or ?rails=all) to receive every available rail in accepts.",
"optin_header": "X-Payment-Network",
"also_advertised_as": {
"note": "This same 402 is offered twice: the v1 challenge in this body, and a v2 challenge in the PAYMENT-REQUIRED header. They are the SAME offer - identical price, asset and payTo - not two competing ones. Pay with whichever version your client speaks; you do not need both.",
"rails": "The v2 challenge lists the Solana rail without an opt-in, while this v1 body does not. That is deliberate, not a discrepancy: a v1 network:\"solana\" entry makes some v1 clients reject the WHOLE accepts array, so v1 advertises it only on request. A v2 client matches on solana:5eykt4Us... and is unaffected.",
"header": "PAYMENT-REQUIRED",
"naming": "The v2 challenge uses CAIP-2 network ids (eip155:8453, solana:5eykt4Us...) where this v1 body uses the legacy short names (base, solana). Same chains, different identifier scheme - CDP couples the naming to the version, so it cannot be mixed.",
"encoding": "base64 JSON",
"x402_version": 2
}
},
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x2d16a243ba9fAcC6AC85519d5efad2149DC4C6c3",
"amount": "5000",
"scheme": "exact",
"network": "base",
"mimeType": "application/json",
"resource": "https://api.truthbear.co/gauge/calibrated",
"extensions": {
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"entity": "required - monitored object id, paired with signal_id; free list at GET /gauge/catalog?signal_id=<signal_id> -> signals[",
"signal_id": "required - signal id (genus.species); free list at GET /gauge/catalog (paged; ?all=1 for every line)"
}
},
"output": {
"type": "json",
"example": {
"dim": "calibrated",
"grade": "screening-level, not decision-grade",
"scope": {
"full": "https://api.truthbear.co/scope/v1",
"verifiability": "via-endpoint",
"monitoring_not_forecast": true,
"intelligence_not_command": true
},
"entity": "07010000",
"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",
"calibrated": {
"band": "below_action",
"unit": "ft",
"scale": "flood_stage",
"metric": "gauge_height_ft",
"index_basis": "normalized_index: piecewise linear (action=0/minor=1/moderate=2/major=3); below the first band = (value - first threshold) / first threshold, clamped to [-1,0); above the top band it is unbounded. pct_to_action = value / first alert threshold (bounded, 1 = at the first alert)",
"current_value": 6.48,
"pct_to_action": 0.231,
"normalized_index": -0.769
},
"provenance": {
"freshness": "fresh",
"age_hours_now": 5.5,
"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/07010000/",
"entity_name": "Mississippi River at St. Louis, MO",
"observed_at": "2026-08-26T09:30:00.000Z",
"record_hash": "sha256:a3986d8689a1d9f6e8b4b92c2318d5af64291cdedbdbd3d706e0049e16fcb42e",
"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."
}
}
}
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method",
"queryParams"
],
"properties": {
"type": {
"const": "http"
},
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"type": "object",
"required": [
"signal_id",
"entity"
],
"properties": {
"entity": {
"type": "string",
"examples": [
"07010000"
],
"description": "required - monitored object id, paired with signal_id; free list at GET /gauge/catalog?signal_id=<signal_id> -> signals[0].entities[]"
},
"signal_id": {
"type": "string",
"examples": [
"hydrology.river-level"
],
"description": "required - signal id (genus.species); free list at GET /gauge/catalog (paged; ?all=1 for every line)"
}
},
"additionalProperties": false
}
}
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"const": "json"
},
"example": {}
}
}
}
},
"priceUsd": "$0.005",
"discoverable": true,
"outputSchema": {
"type": "object",
"required": [
"nature",
"dim",
"calibrated"
],
"properties": {
"dim": {
"type": "string",
"description": "Always the literal \"calibrated\""
},
"grade": {
"type": [
"string",
"null"
],
"description": "Honest data-grade disclosure (e.g. \"screening-level, not decision-grade\")"
},
"scope": {
"type": [
"string",
"null"
],
"description": "Honest statement of scope and limits: monitoring is not forecasting, intelligence is not instruction, and the boundary of what is verifiable"
},
"entity": {
"type": "string",
"description": "Monitored object id (e.g. btc / us / hormuz); full list at free /gauge/catalog or /gauge/preview"
},
"nature": {
"type": "string",
"description": "Neutrality statement: GAUGE supplies observations and trend description only - no judgement, no prediction, no recommendation"
},
"_citation": {
"type": [
"object",
"null"
],
"description": "Offline-verifiable citation: {statement_type, not_advice:bool, claim, fact, source, record_hash, signature(Ed25519), key_id, issuer_DID(did:key), verify_url} - the trust root for zero-trust self-verification"
},
"signal_id": {
"type": "string",
"description": "Signal id in genus.species ASCII binomial form (e.g. crypto.spot / macro.unemployment / shipping.route-disruption); full list at free /gauge/catalog"
},
"calibrated": {
"type": [
"object",
"null"
],
"description": "Calibrated-unit projection: normalized_index / pct_to_action, comparable across stations"
},
"provenance": {
"type": [
"object",
"null"
],
"description": "Data lineage: {served_from, data_as_of, oldest_leg_as_of, data_age_hours (frozen age, reference only), age_hours_now (age computed at request time - the real basis for freshness), freshness(fresh|recent|stale), freshness_basis (the cadence and threshold used for this row, as a string), dead_source (optional: upstream frozen or discontinued), data_lineage:[{signal,traceable_to,uncertainty,record_hash,...}], validation_status}. Freshness is cadence-aware, so monthly/quarterly/annual official lines are not misjudged against a 24h rule; the same basis is used by free /gauge/coverage. Buyers can trace back to the official source"
},
"entity_name": {
"type": [
"string",
"null"
],
"description": "Human-readable name of the object"
},
"observed_at": {
"type": "string",
"description": "Actual observation time of the data, ISO-8601"
},
"record_hash": {
"type": [
"string",
"null"
],
"description": "sha256:<64hex> (contract A v3, binds the values plus provenance)"
},
"data_age_hours": {
"type": [
"number",
"null"
],
"description": "Age frozen at collection time (0 = same hour), for reference only - if a collector stalls this field stops moving. For freshness always use provenance.age_hours_now (computed at request time) and provenance.freshness; the threshold basis is in provenance.freshness_basis"
},
"decision_points": {
"type": [
"object",
"null"
],
"description": "{count, points:[{tag,current,swappable,how}], note} - decision points you can re-run with a swapped tag (one swapped tag = one call); leave it alone and the original context is the default, at no extra charge"
},
"source_agreement_cv": {
"type": [
"number",
"null"
],
"description": "Multi-source agreement, coefficient of variation (smaller = closer agreement). Present ONLY when two or more CONFIRMED-INDEPENDENT sources measure the same fact at the same time - see sources[].independent. Same source relayed through two channels does not count as independent, and two different time bases (daily mean vs spot) do not count as agreement. Single-source / unconfirmed independence / not applicable -> null"
},
"record_hash_verifiable": {
"type": [
"object",
"null"
],
"description": "{mode:offline|via-endpoint, note}"
}
},
"additionalProperties": true,
"conditionalProperties": {
"last_fact": {
"type": [
"object",
"null"
],
"description": "Most recent qualifying fact for this line and entity, attached centrally (may be absent when the line has no qualifying fact yet)"
},
"decision_points": {
"type": [
"object",
"null"
],
"description": "Swappable decision points for this entity, attached centrally: {count, points:[{tag,current,swappable,how}], note}. Present only when the entity has at least one swappable tag in the index, so bundles for entities without one omit it"
},
"leg_availability": {
"type": [
"object",
"null"
],
"description": "Per-leg degradation disclosure: which legs are present, which are degraded and why. Present only when at least one leg is degraded"
},
"record_hash_verifiable": {
"type": [
"object",
"null"
],
"description": "Whether this response can recompute its own record_hash offline. Present only when the payload carries a top-level record_hash; may be absent on list-shaped deliveries where verifiability is stated per row instead"
}
}
},
"routeTemplate": "/gauge/calibrated",
"priceUsdNumber": 0.005
}
},
"description": "Add-on, calibrated units: normalized_index and pct_to_action so readings compare across stations. When the line has no calibration basis you get 422 with no_charge:true and reason:no-calibrated-for-this-line, and are NOT billed. Every record carries an offline-recomputable record_hash. $0.0050 per call.",
"outputSchema": {
"input": {
"type": "http",
"method": "GET",
"example": {
"entity": "07010000",
"format": "thin",
"signal_id": "hydrology.river-level"
},
"required": [
"signal_id",
"entity"
],
"properties": {
"entity": {
"type": "string",
"examples": [
"07010000"
],
"description": "required - monitored object id, paired with signal_id; free list at GET /gauge/catalog?signal_id=<signal_id> -> signals[0].entities[]"
},
"signal_id": {
"type": "string",
"examples": [
"hydrology.river-level"
],
"description": "required - signal id (genus.species); free list at GET /gauge/catalog (paged; ?all=1 for every line)"
}
},
"queryParams": {
"entity": "required - monitored object id, paired with signal_id; free list at GET /gauge/catalog?signal_id=<signal_id> -> signals[0].entities[]",
"signal_id": "required - signal id (genus.species); free list at GET /gauge/catalog (paged; ?all=1 for every line)"
},
"discoverable": true,
"exampleRequest": "/gauge/calibrated?signal_id=hydrology.river-level&entity=07010000&format=thin"
},
"output": {
"type": "object",
"required": [
"nature",
"dim",
"calibrated"
],
"properties": {
"dim": {
"type": "string",
"description": "Always the literal \"calibrated\""
},
"grade": {
"type": [
"string",
"null"
],
"description": "Honest data-grade disclosure (e.g. \"screening-level, not decision-grade\")"
},
"scope": {
"type": [
"string",
"null"
],
"description": "Honest statement of scope and limits: monitoring is not forecasting, intelligence is not instruction, and the boundary of what is verifiable"
},
"entity": {
"type": "string",
"description": "Monitored object id (e.g. btc / us / hormuz); full list at free /gauge/catalog or /gauge/preview"
},
"nature": {
"type": "string",
"description": "Neutrality statement: GAUGE supplies observations and trend description only - no judgement, no prediction, no recommendation"
},
"_citation": {
"type": [
"object",
"null"
],
"description": "Offline-verifiable citation: {statement_type, not_advice:bool, claim, fact, source, record_hash, signature(Ed25519), key_id, issuer_DID(did:key), verify_url} - the trust root for zero-trust self-verification"
},
"signal_id": {
"type": "string",
"description": "Signal id in genus.species ASCII binomial form (e.g. crypto.spot / macro.unemployment / shipping.route-disruption); full list at free /gauge/catalog"
},
"calibrated": {
"type": [
"object",
"null"
],
"description": "Calibrated-unit projection: normalized_index / pct_to_action, comparable across stations"
},
"provenance": {
"type": [
"object",
"null"
],
"description": "Data lineage: {served_from, data_as_of, oldest_leg_as_of, data_age_hours (frozen age, reference only), age_hours_now (age computed at request time - the real basis for freshness), freshness(fresh|recent|stale), freshness_basis (the cadence and threshold used for this row, as a string), dead_source (optional: upstream frozen or discontinued), data_lineage:[{signal,traceable_to,uncertainty,record_hash,...}], validation_status}. Freshness is cadence-aware, so monthly/quarterly/annual official lines are not misjudged against a 24h rule; the same basis is used by free /gauge/coverage. Buyers can trace back to the official source"
},
"entity_name": {
"type": [
"string",
"null"
],
"description": "Human-readable name of the object"
},
"observed_at": {
"type": "string",
"description": "Actual observation time of the data, ISO-8601"
},
"record_hash": {
"type": [
"string",
"null"
],
"description": "sha256:<64hex> (contract A v3, binds the values plus provenance)"
},
"data_age_hours": {
"type": [
"number",
"null"
],
"description": "Age frozen at collection time (0 = same hour), for reference only - if a collector stalls this field stops moving. For freshness always use provenance.age_hours_now (computed at request time) and provenance.freshness; the threshold basis is in provenance.freshness_basis"
},
"decision_points": {
"type": [
"object",
"null"
],
"description": "{count, points:[{tag,current,swappable,how}], note} - decision points you can re-run with a swapped tag (one swapped tag = one call); leave it alone and the original context is the default, at no extra charge"
},
"source_agreement_cv": {
"type": [
"number",
"null"
],
"description": "Multi-source agreement, coefficient of variation (smaller = closer agreement). Present ONLY when two or more CONFIRMED-INDEPENDENT sources measure the same fact at the same time - see sources[].independent. Same source relayed through two channels does not count as independent, and two different time bases (daily mean vs spot) do not count as agreement. Single-source / unconfirmed independence / not applicable -> null"
},
"record_hash_verifiable": {
"type": [
"object",
"null"
],
"description": "{mode:offline|via-endpoint, note}"
}
},
"additionalProperties": true,
"conditionalProperties": {
"last_fact": {
"type": [
"object",
"null"
],
"description": "Most recent qualifying fact for this line and entity, attached centrally (may be absent when the line has no qualifying fact yet)"
},
"decision_points": {
"type": [
"object",
"null"
],
"description": "Swappable decision points for this entity, attached centrally: {count, points:[{tag,current,swappable,how}], note}. Present only when the entity has at least one swappable tag in the index, so bundles for entities without one omit it"
},
"leg_availability": {
"type": [
"object",
"null"
],
"description": "Per-leg degradation disclosure: which legs are present, which are degraded and why. Present only when at least one leg is degraded"
},
"record_hash_verifiable": {
"type": [
"object",
"null"
],
"description": "Whether this response can recompute its own record_hash offline. Present only when the payload carries a top-level record_hash; may be absent on list-shaped deliveries where verifiability is stated per row instead"
}
}
}
},
"maxAmountRequired": "5000",
"maxTimeoutSeconds": 300
}
],
"x402Version": 1
}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
Pay 0.005 USDC on Base to 0x2d16…4c6c3. The signed payment is good for 5 minutes.
- Paid to
- 0x2d16…4c6c3
- USD Coin contract
- 0x8335…02913
- Payment window
- 5 minutes
- As published
- 5000 smallest units
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- 8qEn3Y…QAY3n
- Token contract
- EPjFWd…TDt1v
- Payment window
- 5 minutes
The catalog’s raw entry
[
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x2d16a243ba9facc6ac85519d5efad2149dc4c6c3",
"amount": "5000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
},
{
"asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
"extra": {
"feePayer": "BFK9TLC3edb13K6v4YyH3DwPb5DSUpkWvb7XnqCL9b4F"
},
"payTo": "8qEn3Y3GPXdQ28LHshPa4UYeD8V38Lq9b4jCRirQAY3n",
"amount": "5000",
"scheme": "exact",
"network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
"maxTimeoutSeconds": 300
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"example": {
"entity": "07010000",
"format": "thin",
"signal_id": "hydrology.river-level"
},
"queryParams": {
"entity": "required - monitored object id, paired with signal_id; free list at GET /gauge/catalog?signal_id=<signal_id> -> signals[",
"signal_id": "required - signal id (genus.species); free list at GET /gauge/catalog (paged; ?all=1 for every line)"
},
"exampleRequest": "/gauge/calibrated?signal_id=hydrology.river-level&entity=07010000&format=thin"
},
"output": {
"type": "json",
"example": {
"dim": "calibrated",
"grade": "screening-level, not decision-grade",
"scope": {
"full": "https://api.truthbear.co/scope/v1",
"verifiability": "via-endpoint",
"monitoring_not_forecast": true,
"intelligence_not_command": true
},
"entity": "07010000",
"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",
"calibrated": {
"band": "below_action",
"unit": "ft",
"scale": "flood_stage",
"metric": "gauge_height_ft",
"index_basis": "normalized_index: piecewise linear (action=0/minor=1/moderate=2/major=3); below the first band = (value - first threshold) / first threshold, clamped to [-1,0); above the top band it is unbounded. pct_to_action = value / first alert threshold (bounded, 1 = at the first alert)",
"current_value": 6.48,
"pct_to_action": 0.231,
"normalized_index": -0.769
},
"provenance": {
"freshness": "fresh",
"age_hours_now": 5.5,
"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/07010000/",
"entity_name": "Mississippi River at St. Louis, MO",
"observed_at": "2026-08-26T09:30:00.000Z",
"record_hash": "sha256:a3986d8689a1d9f6e8b4b92c2318d5af64291cdedbdbd3d706e0049e16fcb42e",
"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."
}
}
}
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method",
"queryParams"
],
"properties": {
"type": {
"const": "http"
},
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"type": "object",
"required": [
"signal_id",
"entity"
],
"properties": {
"entity": {
"type": "string",
"examples": [
"07010000"
],
"description": "required - monitored object id, paired with signal_id; free list at GET /gauge/catalog?signal_id=<signal_id> -> signals[0].entities[]"
},
"signal_id": {
"type": "string",
"examples": [
"hydrology.river-level"
],
"description": "required - signal id (genus.species); free list at GET /gauge/catalog (paged; ?all=1 for every line)"
}
},
"additionalProperties": false
}
}
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"const": "json"
},
"example": {}
}
}
}
},
"priceUsd": "$0.005",
"discoverable": true,
"routeTemplate": "/gauge/calibrated",
"priceUsdNumber": 0.005,
"outputSchemaRef": "/manifest"
}
}Provenance
- Seen in the source catalog
- 2026-09-07 08:52Z
- Last indexed by Roundhouse
- 2026-09-24 11:30Z
- Last enriched (probe, favicon, geo)
- 2026-09-23 21:15Z
- x402 version
- 2
- Max timeout
- 300s
- Liveness probe
- HTTP 402
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 30 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service Truth Bear and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=Truth%20Bear' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://api.truthbear.co/gauge/calibrated, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402, or use an organization key from https://roundhouseai.io/dashboard/team. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.