> ## Documentation Index > Fetch the complete documentation index at: https://docs.tazolabs.com/llms.txt > Use this file to discover all available pages before exploring further. # Stream decisions > Send audio over a WebSocket connection and receive typed decisions. Connect to `wss://api.tazolabs.com/v1/decisions/stream` and send `session.start` within five seconds. Include your API key or access token in its `authorization` field, then wait for `session.ready` before sending audio. Send control messages as JSON and audio as binary PCM16 frames: little-endian, 16 kHz, mono. Audio must be sent as raw bytes, without JSON or base64 encoding. For a walkthrough with request and response examples, see [Streaming decisions](https://docs.tazolabs.com/guides/streaming.md). Try streaming audio in the [Tazo playground](https://app.tazolabs.com). ## AsyncAPI ````yaml api-reference/asyncapi.yaml decisions id: decisions title: Stream decisions description: >- Send audio and receive typed decisions over one WebSocket connection. Chunk mode has no cumulative audio-duration cap and reports max_turn_audio_ms as null. Turn mode reports a numeric model/server limit; commit before exceeding it and wait for decision.finalized before the next turn. servers: - id: production protocol: wss host: api.tazolabs.com bindings: [] variables: [] address: /v1/decisions/stream parameters: [] bindings: [] operations: - &ref_8 id: sendToTazo title: Send to Tazo type: send messages: - &ref_15 id: sessionStart contentType: application/json payload: - name: session.start description: >- Authenticate and configure the session. Wait for session.ready before sending audio. type: object properties: - name: model type: string title: Model required: false - name: state type: anyOf title: State required: true - name: questions type: object title: Questions description: >- Exactly one question. Use Tazo Large. Tazo Small is unavailable through the API; requests receive a fatal model_unavailable error and close code 1008. Contact support@tazolabs.com for assistance. required: true - name: type type: string title: Type description: session.start required: true - name: authorization type: string title: Authorization description: >- Bearer API key or access token. Send in session.start within five seconds of connecting; authentication is checked again when a new turn starts. required: true - name: input_audio type: object title: StreamAudioFormat description: >- Source audio declaration, fixed for the connection. PCM16 supports integer rates from 8000 to 48000 Hz. G.711 mulaw and alaw require an explicit 8000 Hz rate. The server decodes and resamples to mono 16 kHz internally; raw input cannot be autodetected. required: false properties: - name: encoding type: string title: Encoding enumValues: - pcm_s16le - mulaw - alaw required: false - name: sample_rate_hz type: integer title: Sample Rate Hz required: false - name: channels type: integer title: Channels description: 1 required: false - name: evaluation_interval_ms type: integer title: Evaluation Interval Ms description: >- Evaluation interval in milliseconds. The server default is 1000; inference speed also affects response timing. required: false - name: audio_scope type: string title: Audio Scope description: >- chunk evaluates new audio only; turn evaluates all audio in the current turn. enumValues: - turn - chunk required: false headers: [] jsonPayloadSchema: additionalProperties: false description: >- Request text uses the account's character limit (1,000 by default); see the Limits guide. Exceeding it returns fatal request_text_too_long and closes with code 1008. properties: model: default: tazo-large minLength: 1 title: Model type: string x-parser-schema-id: state: anyOf: - type: string x-parser-schema-id: - additionalProperties: true type: object x-parser-schema-id: - items: type: string x-parser-schema-id: type: array x-parser-schema-id: title: State x-parser-schema-id: questions: additionalProperties: oneOf: - &ref_0 additionalProperties: false properties: type: const: choice title: Type type: string x-parser-schema-id: instructions: anyOf: - type: string x-parser-schema-id: - additionalProperties: true type: object x-parser-schema-id: - items: type: string x-parser-schema-id: type: array x-parser-schema-id: title: Instructions x-parser-schema-id: criteria: additionalProperties: anyOf: - type: string x-parser-schema-id: - additionalProperties: true type: object x-parser-schema-id: - items: type: string x-parser-schema-id: type: array x-parser-schema-id: - type: 'null' x-parser-schema-id: x-parser-schema-id: maxProperties: 255 minProperties: 2 title: Criteria type: object x-parser-schema-id: required: - type - instructions - criteria title: ChoiceQuestion type: object x-parser-schema-id: ChoiceQuestion - &ref_1 additionalProperties: false properties: type: const: noul title: Type type: string x-parser-schema-id: instructions: anyOf: - type: string x-parser-schema-id: - additionalProperties: true type: object x-parser-schema-id: - items: type: string x-parser-schema-id: type: array x-parser-schema-id: title: Instructions x-parser-schema-id: criteria: anyOf: - additionalProperties: anyOf: - type: string x-parser-schema-id: - additionalProperties: true type: object x-parser-schema-id: - items: type: string x-parser-schema-id: type: array x-parser-schema-id: - type: 'null' x-parser-schema-id: x-parser-schema-id: type: object x-parser-schema-id: - type: 'null' x-parser-schema-id: default: null title: Criteria x-parser-schema-id: required: - type - instructions title: NoulQuestion type: object x-parser-schema-id: NoulQuestion x-parser-schema-id: maxProperties: 1 minProperties: 1 title: Questions type: object description: >- Exactly one question. Use Tazo Large. Tazo Small is unavailable through the API; requests receive a fatal model_unavailable error and close code 1008. Contact support@tazolabs.com for assistance. x-parser-schema-id: type: const: session.start title: Type type: string x-parser-schema-id: authorization: format: password title: Authorization type: string writeOnly: true description: >- Bearer API key or access token. Send in session.start within five seconds of connecting; authentication is checked again when a new turn starts. x-parser-schema-id: input_audio: &ref_2 additionalProperties: false description: >- Source audio declaration, fixed for the connection. PCM16 supports integer rates from 8000 to 48000 Hz. G.711 mulaw and alaw require an explicit 8000 Hz rate. The server decodes and resamples to mono 16 kHz internally; raw input cannot be autodetected. properties: encoding: enum: - pcm_s16le - mulaw - alaw default: pcm_s16le title: Encoding type: string x-parser-schema-id: sample_rate_hz: minimum: 8000 maximum: 48000 default: 16000 title: Sample Rate Hz type: integer x-parser-schema-id: channels: const: 1 default: 1 title: Channels type: integer x-parser-schema-id: title: StreamAudioFormat type: object oneOf: - properties: encoding: const: pcm_s16le x-parser-schema-id: - required: - encoding - sample_rate_hz properties: encoding: enum: - mulaw - alaw sample_rate_hz: const: 8000 x-parser-schema-id: x-parser-schema-id: StreamAudioFormat evaluation_interval_ms: anyOf: - maximum: 30000 minimum: 250 type: integer x-parser-schema-id: - type: 'null' x-parser-schema-id: default: null title: Evaluation Interval Ms description: >- Evaluation interval in milliseconds. The server default is 1000; inference speed also affects response timing. x-parser-schema-id: audio_scope: default: chunk enum: - turn - chunk title: Audio Scope type: string description: >- chunk evaluates new audio only; turn evaluates all audio in the current turn. x-parser-schema-id: required: - state - questions - type - authorization title: SessionStart type: object x-parser-schema-id: SessionStart title: session.start description: >- Authenticate and configure the session. Wait for session.ready before sending audio. example: |- { "type": "session.start", "authorization": "Bearer YOUR_API_KEY", "model": "tazo-large", "audio_scope": "chunk", "evaluation_interval_ms": 1000, "state": { "context": "Choose the tool matching the spoken request." }, "questions": { "action": { "type": "choice", "instructions": "Which action should be taken?", "criteria": { "NO_TOOL": "Respond directly without calling a tool.", "get_weather": "Get weather for a city." } } }, "input_audio": { "encoding": "pcm_s16le", "sample_rate_hz": 16000, "channels": 1 } } bindings: [] extensions: - id: x-parser-unique-object-id value: sessionStart - &ref_16 id: audio contentType: application/octet-stream payload: - type: string format: binary minLength: 1 maxLength: 19200 x-parser-schema-id: name: Binary audio description: >- Send raw mono audio matching session.start.input_audio after session.ready. headers: [] jsonPayloadSchema: type: string format: binary minLength: 1 maxLength: 19200 x-parser-schema-id: title: Binary audio description: >- Send raw mono audio matching session.start.input_audio after session.ready. example: '{}' bindings: [] extensions: - id: x-parser-unique-object-id value: audio - &ref_17 id: sessionUpdate contentType: application/json payload: - name: session.update description: >- Between turns, replace both state and questions. Wait for session.updated before sending audio. type: object properties: - name: type type: string title: Type description: session.update required: true - name: state type: anyOf title: State required: true - name: questions type: object title: Questions required: true headers: [] jsonPayloadSchema: additionalProperties: false description: >- The session.start text limit applies. Exceeding it returns nonfatal request_text_too_long and preserves the previous configuration and revision. properties: type: const: session.update title: Type type: string x-parser-schema-id: state: anyOf: - type: string x-parser-schema-id: - additionalProperties: true type: object x-parser-schema-id: - items: type: string x-parser-schema-id: type: array x-parser-schema-id: title: State x-parser-schema-id: questions: additionalProperties: oneOf: - *ref_0 - *ref_1 x-parser-schema-id: maxProperties: 1 minProperties: 1 title: Questions type: object x-parser-schema-id: required: - type - state - questions title: SessionUpdate type: object x-parser-schema-id: SessionUpdate title: session.update description: >- Between turns, replace both state and questions. Wait for session.updated before sending audio. example: |- { "type": "session.update", "state": { "context": "Choose the tool matching the spoken request." }, "questions": { "action": { "type": "choice", "instructions": "Which action should be taken?", "criteria": { "NO_TOOL": "Respond directly without calling a tool.", "get_weather": "Get weather for a city." } } } } bindings: [] extensions: - id: x-parser-unique-object-id value: sessionUpdate - &ref_18 id: inputCommit contentType: application/json payload: - name: input.commit description: >- Complete the current turn. Wait for decision.finalized before sending more audio. type: object properties: - name: type type: string title: Type description: input.commit required: true headers: [] jsonPayloadSchema: additionalProperties: false properties: type: const: input.commit title: Type type: string x-parser-schema-id: required: - type title: InputCommit type: object x-parser-schema-id: InputCommit title: input.commit description: >- Complete the current turn. Wait for decision.finalized before sending more audio. example: |- { "type": "input.commit" } bindings: [] extensions: - id: x-parser-unique-object-id value: inputCommit - &ref_19 id: inputFinish contentType: application/json payload: - name: input.finish description: Complete pending audio and close the session. type: object properties: - name: type type: string title: Type description: input.finish required: true headers: [] jsonPayloadSchema: additionalProperties: false properties: type: const: input.finish title: Type type: string x-parser-schema-id: required: - type title: InputFinish type: object x-parser-schema-id: InputFinish title: input.finish description: Complete pending audio and close the session. example: |- { "type": "input.finish" } bindings: [] extensions: - id: x-parser-unique-object-id value: inputFinish bindings: [] extensions: &ref_6 - id: x-parser-unique-object-id value: decisions - &ref_7 id: receiveFromTazo title: Receive from Tazo type: receive messages: - &ref_9 id: sessionReady contentType: application/json payload: - name: session.ready description: >- The session is ready. Read the effective audio format, interval, scope, and limits. type: object properties: - name: session_id type: string title: Session Id required: true - name: sequence type: integer title: Sequence required: true - name: type type: string title: Type description: session.ready required: true - name: model type: string title: Model required: true - name: config_revision type: integer title: Config Revision required: true - name: input_audio type: object title: StreamAudioFormat description: >- Source audio declaration, fixed for the connection. PCM16 supports integer rates from 8000 to 48000 Hz. G.711 mulaw and alaw require an explicit 8000 Hz rate. The server decodes and resamples to mono 16 kHz internally; raw input cannot be autodetected. required: true properties: - name: encoding type: string title: Encoding enumValues: - pcm_s16le - mulaw - alaw required: false - name: sample_rate_hz type: integer title: Sample Rate Hz required: false - name: channels type: integer title: Channels description: 1 required: false - name: evaluation_interval_ms type: integer title: Evaluation Interval Ms required: true - name: max_turn_audio_ms type: integer title: Max Turn Audio Ms description: >- Null for continuous chunk streams; otherwise the maximum audio duration per turn. required: true - name: max_audio_message_bytes type: integer title: Max Audio Message Bytes required: true - name: audio_scope type: string title: Audio Scope enumValues: - turn - chunk required: false headers: [] jsonPayloadSchema: additionalProperties: false properties: session_id: title: Session Id type: string x-parser-schema-id: sequence: minimum: 1 title: Sequence type: integer x-parser-schema-id: type: const: session.ready title: Type type: string x-parser-schema-id: model: title: Model type: string x-parser-schema-id: config_revision: minimum: 1 title: Config Revision type: integer x-parser-schema-id: input_audio: *ref_2 evaluation_interval_ms: exclusiveMinimum: 0 title: Evaluation Interval Ms type: integer x-parser-schema-id: max_turn_audio_ms: anyOf: - exclusiveMinimum: 0 type: integer x-parser-schema-id: - type: 'null' x-parser-schema-id: title: Max Turn Audio Ms description: >- Null for continuous chunk streams; otherwise the maximum audio duration per turn. x-parser-schema-id: max_audio_message_bytes: exclusiveMinimum: 0 title: Max Audio Message Bytes type: integer x-parser-schema-id: audio_scope: default: chunk enum: - turn - chunk title: Audio Scope type: string x-parser-schema-id: required: - session_id - sequence - type - model - config_revision - input_audio - evaluation_interval_ms - max_turn_audio_ms - max_audio_message_bytes title: SessionReady type: object x-parser-schema-id: SessionReady title: session.ready description: >- The session is ready. Read the effective audio format, interval, scope, and limits. example: |- { "type": "session.ready", "session_id": "ses_example", "sequence": 1, "model": "tazo-large", "config_revision": 1, "input_audio": { "encoding": "pcm_s16le", "sample_rate_hz": 16000, "channels": 1 }, "evaluation_interval_ms": 1000, "max_turn_audio_ms": null, "max_audio_message_bytes": 6400, "audio_scope": "chunk" } bindings: [] extensions: - id: x-parser-unique-object-id value: sessionReady - &ref_10 id: sessionUpdated contentType: application/json payload: - name: session.updated description: The replacement context and question were accepted. type: object properties: - name: session_id type: string title: Session Id required: true - name: sequence type: integer title: Sequence required: true - name: type type: string title: Type description: session.updated required: true - name: config_revision type: integer title: Config Revision required: true headers: [] jsonPayloadSchema: additionalProperties: false properties: session_id: title: Session Id type: string x-parser-schema-id: sequence: minimum: 1 title: Sequence type: integer x-parser-schema-id: type: const: session.updated title: Type type: string x-parser-schema-id: config_revision: minimum: 1 title: Config Revision type: integer x-parser-schema-id: required: - session_id - sequence - type - config_revision title: SessionUpdated type: object x-parser-schema-id: SessionUpdated title: session.updated description: The replacement context and question were accepted. example: |- { "type": "session.updated", "session_id": "ses_example", "sequence": 4, "config_revision": 2 } bindings: [] extensions: - id: x-parser-unique-object-id value: sessionUpdated - &ref_11 id: decisionUpdated contentType: application/json payload: - allOf: &ref_3 - &ref_4 additionalProperties: false properties: session_id: title: Session Id type: string x-parser-schema-id: sequence: minimum: 1 title: Sequence type: integer x-parser-schema-id: id: pattern: ^dec_[A-Za-z0-9_-]+$ title: Id type: string x-parser-schema-id: model: title: Model type: string x-parser-schema-id: answers: additionalProperties: oneOf: - additionalProperties: false properties: type: const: choice title: Type type: string x-parser-schema-id: choice: title: Choice type: string x-parser-schema-id: probabilities: additionalProperties: type: number x-parser-schema-id: title: Probabilities type: object x-parser-schema-id: confidence: maximum: 1 minimum: 0 title: Confidence type: number x-parser-schema-id: required: - type - choice - probabilities - confidence title: ChoiceAnswer type: object x-parser-schema-id: ChoiceAnswer - additionalProperties: false properties: type: const: noul title: Type type: string x-parser-schema-id: noul: maximum: 1 minimum: 0 title: Noul type: number x-parser-schema-id: required: - type - noul title: NoulAnswer type: object x-parser-schema-id: NoulAnswer x-parser-schema-id: minProperties: 1 title: Answers type: object x-parser-schema-id: usage: additionalProperties: false properties: audio_seconds: minimum: 0 title: Audio Seconds type: number x-parser-schema-id: input_tokens: anyOf: - minimum: 0 type: integer x-parser-schema-id: - type: 'null' x-parser-schema-id: default: null title: Input Tokens x-parser-schema-id: output_tokens: anyOf: - minimum: 0 type: integer x-parser-schema-id: - type: 'null' x-parser-schema-id: default: null title: Output Tokens x-parser-schema-id: required: - audio_seconds title: Usage type: object x-parser-schema-id: Usage elapsed_ms: minimum: 0 title: Elapsed Ms type: number x-parser-schema-id: type: enum: - decision.updated - decision.finalized title: Type type: string x-parser-schema-id: turn_id: title: Turn Id type: string x-parser-schema-id: config_revision: minimum: 1 title: Config Revision type: integer x-parser-schema-id: audio_start_ms: default: 0 minimum: 0 title: Audio Start Ms type: number x-parser-schema-id: audio_end_ms: minimum: 0 title: Audio End Ms type: number x-parser-schema-id: required: - session_id - sequence - id - model - answers - usage - elapsed_ms - type - turn_id - config_revision - audio_end_ms title: StreamDecisionEvent type: object x-parser-schema-id: StreamDecisionEvent - type: object properties: type: const: decision.updated x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: name: decision.updated description: >- A decision for the reported audio range while audio continues arriving. headers: [] jsonPayloadSchema: allOf: *ref_3 x-parser-schema-id: title: decision.updated description: >- A decision for the reported audio range while audio continues arriving. example: |- { "type": "decision.updated", "session_id": "ses_example", "sequence": 2, "turn_id": "turn_1", "config_revision": 1, "id": "dec_example", "model": "tazo-large", "audio_start_ms": 0, "audio_end_ms": 500, "answers": { "action": { "type": "choice", "choice": "get_weather", "probabilities": { "NO_TOOL": 0.08, "get_weather": 0.92 }, "confidence": 0.92 } }, "usage": { "audio_seconds": 0.5 }, "elapsed_ms": 52 } bindings: [] extensions: - id: x-parser-unique-object-id value: decisionUpdated - &ref_12 id: decisionFinalized contentType: application/json payload: - allOf: &ref_5 - *ref_4 - type: object properties: type: const: decision.finalized x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: name: decision.finalized description: >- The turn is complete. In chunk mode this is the last chunk result, not a summary of the turn. headers: [] jsonPayloadSchema: allOf: *ref_5 x-parser-schema-id: title: decision.finalized description: >- The turn is complete. In chunk mode this is the last chunk result, not a summary of the turn. example: |- { "type": "decision.finalized", "session_id": "ses_example", "sequence": 3, "turn_id": "turn_1", "config_revision": 1, "id": "dec_example", "model": "tazo-large", "audio_start_ms": 0, "audio_end_ms": 500, "answers": { "action": { "type": "choice", "choice": "get_weather", "probabilities": { "NO_TOOL": 0.08, "get_weather": 0.92 }, "confidence": 0.92 } }, "usage": { "audio_seconds": 0.5 }, "elapsed_ms": 52 } bindings: [] extensions: - id: x-parser-unique-object-id value: decisionFinalized - &ref_13 id: sessionClosed contentType: application/json payload: - name: session.closed description: The server is closing the session after input.finish. type: object properties: - name: session_id type: string title: Session Id required: true - name: sequence type: integer title: Sequence required: true - name: type type: string title: Type description: session.closed required: true headers: [] jsonPayloadSchema: additionalProperties: false properties: session_id: title: Session Id type: string x-parser-schema-id: sequence: minimum: 1 title: Sequence type: integer x-parser-schema-id: type: const: session.closed title: Type type: string x-parser-schema-id: required: - session_id - sequence - type title: SessionClosed type: object x-parser-schema-id: SessionClosed title: session.closed description: The server is closing the session after input.finish. example: |- { "type": "session.closed", "session_id": "ses_example", "sequence": 4 } bindings: [] extensions: - id: x-parser-unique-object-id value: sessionClosed - &ref_14 id: error contentType: application/json payload: - name: error description: An error occurred. A fatal error closes the connection. type: object properties: - name: type type: string title: Type description: error required: true - name: session_id type: string title: Session Id required: false - name: sequence type: integer title: Sequence required: false - name: error type: object title: StreamErrorDetail required: true properties: - name: code type: string title: Code required: true - name: message type: string title: Message required: true - name: fatal type: boolean title: Fatal required: true headers: [] jsonPayloadSchema: additionalProperties: false properties: type: const: error title: Type type: string x-parser-schema-id: session_id: anyOf: - type: string x-parser-schema-id: - type: 'null' x-parser-schema-id: default: null title: Session Id x-parser-schema-id: sequence: anyOf: - minimum: 1 type: integer x-parser-schema-id: - type: 'null' x-parser-schema-id: default: null title: Sequence x-parser-schema-id: error: additionalProperties: false properties: code: title: Code type: string x-parser-schema-id: message: title: Message type: string x-parser-schema-id: required: - code - message title: StreamErrorDetail type: object x-parser-schema-id: StreamErrorDetail fatal: title: Fatal type: boolean x-parser-schema-id: required: - type - error - fatal title: StreamError type: object x-parser-schema-id: StreamError title: Error description: An error occurred. A fatal error closes the connection. example: |- { "type": "error", "session_id": "ses_example", "sequence": 3, "fatal": true, "error": { "code": "turn_too_long", "message": "The turn exceeds its audio limit; commit before sending more." } } bindings: [] extensions: - id: x-parser-unique-object-id value: error bindings: [] extensions: *ref_6 sendOperations: - *ref_7 receiveOperations: - *ref_8 sendMessages: - *ref_9 - *ref_10 - *ref_11 - *ref_12 - *ref_13 - *ref_14 receiveMessages: - *ref_15 - *ref_16 - *ref_17 - *ref_18 - *ref_19 extensions: - id: x-parser-unique-object-id value: decisions securitySchemes: [] ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.