> ## Documentation Index > Fetch the complete documentation index at: https://docs.tracks.alpic.ai/llms.txt > Use this file to discover all available pages before exploring further. # Stream a run's frames > Sends the agent's output as server-sent events as it is produced: a `frame` event per line, its data the line as JSON, and a `heartbeat` event every 30 seconds to keep the connection open. Closes once the run has ended and every line was sent. The connection may also close earlier; to pick up where it stopped, call again with the `seq` of the last line received as `after`, or let an SSE client reconnect: the `Last-Event-ID` header it sends is used when `after` is absent. ## OpenAPI ````yaml https://tracks.alpic.ai/api/openapi.json get /runs/{id}/frames/stream openapi: 3.1.0 info: title: Tracks API version: 0.0.1 description: >- Run coding agents such as Claude Code in isolated sandboxes with an API key of your organization. Create a run with a prompt, then follow its output and what it costs, or launch an experiment to compare agents on your scenarios. servers: - url: https://tracks.alpic.ai/api security: [] tags: - name: Runs description: Start coding agents and follow their work. - name: Files description: Upload files to place in a run's sandbox. - name: Connections description: >- Let agents use MCP servers as one of their users, without their credentials entering the sandbox. - name: Experiments description: >- Define scenarios to give several agents in several variants, judged on what they did. - name: Executions description: Launch experiments and read their results. - name: Library description: What your experiments can give their agents. - name: System paths: /runs/{id}/frames/stream: get: tags: - Runs summary: Stream a run's frames description: >- Sends the agent's output as server-sent events as it is produced: a `frame` event per line, its data the line as JSON, and a `heartbeat` event every 30 seconds to keep the connection open. Closes once the run has ended and every line was sent. The connection may also close earlier; to pick up where it stopped, call again with the `seq` of the last line received as `after`, or let an SSE client reconnect: the `Last-Event-ID` header it sends is used when `after` is absent. operationId: runs.followFrames parameters: - name: id in: path schema: $ref: '#/components/schemas/RunId' required: true - name: after in: query schema: type: string pattern: ^[+-]?(?:\d+(?:\.\d+)?|\.\d+)(?:[Ee][+-]?\d+)?$ allOf: - description: Send only lines whose `seq` is greater than this. required: false responses: '200': description: Success content: text/event-stream: schema: anyOf: - type: object properties: id: anyOf: - type: string - type: 'null' event: type: string enum: - frame data: $ref: '#/components/schemas/FrameEncoded' required: - event - data additionalProperties: false - type: object properties: id: anyOf: - type: string - type: 'null' event: type: string enum: - heartbeat data: type: string enum: - '' required: - event - data additionalProperties: false x-effect-stream: encoding: sse causeSchema: type: array items: anyOf: - type: object properties: _tag: type: string enum: - Fail error: not: {} required: - _tag - error additionalProperties: false - type: object properties: _tag: type: string enum: - Die defect: {} required: - _tag - defect additionalProperties: false - type: object properties: _tag: type: string enum: - Interrupt fiberId: anyOf: - type: number - type: 'null' required: - _tag - fiberId additionalProperties: false errorSchema: not: {} failureEvent: effect/http-api/stream/failure '400': description: >- The request is invalid: a value is missing, has the wrong type or is out of range. Fix it before sending the request again. content: application/json: schema: $ref: '#/components/schemas/InvalidRequestEncoded' '401': description: >- The API key is missing, malformed or revoked, or its organization is closed. content: application/json: schema: $ref: '#/components/schemas/ApiKeyRefusedEncoded' '404': description: No run with this id exists in your organization. content: application/json: schema: $ref: '#/components/schemas/RunNotFoundEncoded' security: - bearer: [] components: schemas: RunId: type: string description: Unique identifier of the run. FrameEncoded: type: string contentMediaType: application/json contentSchema: $ref: '#/components/schemas/Frame' InvalidRequestEncoded: type: object properties: _tag: type: string enum: - InvalidRequest message: type: string description: Every problem found, in one sentence. location: type: string enum: - path - query - header - body description: The part of the request that is wrong. issues: type: array items: $ref: '#/components/schemas/RequestIssue' description: Each problem found, with where it is. required: - _tag - message - location - issues additionalProperties: false ApiKeyRefusedEncoded: type: object properties: _tag: type: string enum: - ApiKeyRefused message: type: string required: - _tag - message additionalProperties: false RunNotFoundEncoded: type: object properties: _tag: type: string enum: - RunNotFound message: type: string required: - _tag - message additionalProperties: false RequestIssue: type: object properties: path: type: array items: anyOf: - type: string - type: number - type: string enum: - Infinity - '-Infinity' - NaN description: >- Keys leading to the wrong value inside that part of the request, such as `["agent", "model"]`. Empty when the problem concerns that part as a whole. message: type: string description: What is wrong with the value. required: - path - message additionalProperties: false description: One problem found in the request. securitySchemes: bearer: description: >- An API key of your organization, starting with `trk_`, sent as `Authorization: Bearer `. type: http scheme: bearer ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.