> ## Documentation Index > Fetch the complete documentation index at: https://agora402.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Request a signed quote > Ask the seller what one call will cost before paying. Free and unauthenticated. The seller prices the estimate with the endpoint's pricing model and returns a Quote signed by its Hedera account key, valid for about two minutes. Pass maxAmount to counter below list price: the seller accepts any offer at or above its floor (85% of list by default) and answers 409 with minimumAmount below it. Put quote.quoteId in the body (POST) or query string (GET) of the paid request and the 402 will carry exactly the agreed amount; a quote is consumed by the settlement, so it cannot be replayed. ## OpenAPI ````yaml /openapi.yaml post /a2a/quote openapi: 3.1.0 info: title: Agora402 seller API version: 1.0.0 description: >- HTTP API served by every Agora402 seller: free discovery documents, a free quote endpoint, and paid endpoints gated by x402 and settled on Hedera through the Blocky402 facilitator. Typical agent flow: getManifest (what is sold, at what price, paid to which account) -> requestQuote (lock a signed price, counter below list if you like) -> call the paid endpoint with the quoteId. The first call answers 402 with a PAYMENT-REQUIRED header; the retry carries PAYMENT-SIGNATURE; the response carries PAYMENT-RESPONSE with the Hedera transaction id. Then read listReceipts or the seller's HCS receipts topic to audit what was charged. All amounts are decimal strings in atomic units of the asset (tinybars for HBAR, 8 decimals); timestamps are ISO 8601 unless stated; quote expiry is unix seconds. servers: - url: http://localhost:4402 description: Local services seller (npm run dev) - url: http://localhost:4404 description: Local auditor (npm run dev) security: [] tags: - name: Discovery description: Free documents that describe the seller. Read these before paying anyone. - name: Negotiation description: Free, signed, time-limited price quotes. - name: Paid services description: x402-gated endpoints. Every call is a Hedera micropayment. - name: Trust description: Paid audits of other sellers, attested on the HCS audit topic. - name: Receipts description: What this seller has been paid for. paths: /a2a/quote: post: tags: - Negotiation summary: Request a signed quote description: >- Ask the seller what one call will cost before paying. Free and unauthenticated. The seller prices the estimate with the endpoint's pricing model and returns a Quote signed by its Hedera account key, valid for about two minutes. Pass maxAmount to counter below list price: the seller accepts any offer at or above its floor (85% of list by default) and answers 409 with minimumAmount below it. Put quote.quoteId in the body (POST) or query string (GET) of the paid request and the 402 will carry exactly the agreed amount; a quote is consumed by the settlement, so it cannot be replayed. operationId: requestQuote requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/QuoteRequest' examples: counter: summary: Counter below list price value: endpointId: infer estimate: inputTokens: 120 maxOutputTokens: 256 asset: 0.0.0 maxAmount: '60000' buyer: >- uaid:aid:9GvnzC1pJ7yA4WQ2E;uid=agora-buyer;registry=agora402;proto=a2a;nativeId=hedera:testnet:0.0.4009876 list: summary: Accept the list price value: endpointId: hbar-rate estimate: units: 1 responses: '200': description: Signed quote content: application/json: schema: $ref: '#/components/schemas/QuoteResponse' example: quote: quoteId: q_5f1c2a9b7d3e4c6a8b0f1e2d seller: >- uaid:aid:2NEpo7TZRRrLZSi2U;uid=agora-demo-seller;registry=agora402;proto=a2a;nativeId=hedera:testnet:0.0.5001234;domain=localhost:4402 endpointId: infer network: hedera:testnet asset: 0.0.0 amount: '60000' expiresAt: 1789560120 basis: pricing: kind: per-token base: '50000' inputPer1k: '20000' outputPer1k: '60000' estimate: inputTokens: 120 maxOutputTokens: 256 listPrice: '67760' countered: true buyer: >- uaid:aid:9GvnzC1pJ7yA4WQ2E;uid=agora-buyer;registry=agora402;proto=a2a;nativeId=hedera:testnet:0.0.4009876 signature: >- 3045022100a1b2c3d4e5f60718293a4b5c6d7e8f90a1b2c3d4e5f60718293a4b5c6d7e8f9002200f1e2d3c4b5a69788796a5b4c3d2e1f00f1e2d3c4b5a69788796a5b4c3d2e1f0 signerPublicKey: >- 302d300706052b8104000a032200027a1b2c3d4e5f60718293a4b5c6d7e8f90a1b2c3d4e5f60718293a4b5c6d7e8f9 countered: true '400': description: Invalid body, or the endpoint does not accept the requested asset content: application/json: schema: $ref: '#/components/schemas/QuoteRejection' examples: invalid: value: error: invalid quote request issues: - code: invalid_type path: - endpointId message: Required asset: value: error: endpoint infer does not accept asset 0.0.7777 '404': description: Unknown endpointId content: application/json: schema: $ref: '#/components/schemas/QuoteRejection' example: error: unknown endpoint translate '409': description: >- Offer below the seller's floor. Raise maxAmount to at least minimumAmount, or omit it. content: application/json: schema: $ref: '#/components/schemas/QuoteRejection' example: error: offer below floor minimumAmount: '57596' listPrice: '67760' components: schemas: QuoteRequest: type: object required: - endpointId properties: endpointId: type: string description: id of the endpoint in the manifest, e.g. infer or hbar-rate estimate: type: object description: >- The work to price. Which fields matter depends on the pricing model kind. properties: inputTokens: type: integer minimum: 0 description: per-token models, about 4 characters per token maxOutputTokens: type: integer minimum: 0 description: per-token models, the max_tokens you will send units: type: integer minimum: 0 description: per-unit models, defaults to 1 maxAmount: type: string pattern: ^\d+$ description: >- Your ceiling in atomic units. At or above list you pay list; between floor and list the seller accepts your counter; below floor you get 409. asset: type: string pattern: ^\d+\.\d+\.\d+$ default: 0.0.0 description: Asset to pay in. 0.0.0 is HBAR. buyer: type: string description: Your uaid, informational, echoed in basis.buyer QuoteResponse: type: object required: - quote - countered properties: quote: $ref: '#/components/schemas/Quote' countered: type: boolean description: true when the seller accepted your maxAmount below list price QuoteRejection: type: object required: - error properties: error: type: string issues: type: array description: Zod validation issues, only on invalid bodies items: type: object additionalProperties: true minimumAmount: type: string pattern: ^\d+$ description: The least the seller will take (409 only) listPrice: type: string pattern: ^\d+$ description: Undiscounted price (409 only) Quote: type: object description: A priced, time-limited offer signed by the seller account key required: - quoteId - seller - endpointId - network - asset - amount - expiresAt - basis - signature - signerPublicKey properties: quoteId: type: string minLength: 8 description: q_ followed by 24 hex. Send it with the paid request. seller: $ref: '#/components/schemas/Uaid' endpointId: type: string network: $ref: '#/components/schemas/Network' asset: $ref: '#/components/schemas/HederaEntityId' amount: $ref: '#/components/schemas/Amount' description: Exactly what the 402 will ask for when the quote is used expiresAt: type: integer description: Unix seconds. About 120 seconds after issue. basis: type: object additionalProperties: true description: >- What the price covers, for auditability. The seller includes pricing, estimate, listPrice, countered and buyer. signature: type: string description: >- Hex ECDSA or ED25519 signature over the canonical quote body (sorted keys, everything but signature and signerPublicKey) signerPublicKey: type: string description: >- Hex DER public key of the seller account. Verify it matches the account in payTo. Uaid: type: string pattern: '^uaid:' description: HCS-14 universal agent id example: >- uaid:aid:2NEpo7TZRRrLZSi2U;uid=agora-demo-seller;registry=agora402;proto=a2a;nativeId=hedera:testnet:0.0.5001234;domain=localhost:4402 Network: type: string enum: - hedera:testnet - hedera:mainnet description: CAIP-2 network id HederaEntityId: type: string pattern: ^\d+\.\d+\.\d+$ description: Hedera entity id, shard.realm.num example: 0.0.5001234 Amount: type: string pattern: ^\d+$ description: >- Atomic units of the asset as a decimal string (tinybars for HBAR). Never a float. example: '60000' ````