> ## Documentation Index > Fetch the complete documentation index at: https://checkfu.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Stream a Session thread's events (SSE) > Resumable SSE for one thread's EventEnvelope history. A primary thread receives the condensed Session projection and a child receives its complete history; optional agent.message and agent.thinking previews are live-only and thread-local. Checkfu support posture: alpha; hosted. Required evidence journey: session-threads. Deployment-specific readiness and the latest proven release are available from GET /v1/support/capabilities. ## OpenAPI ````yaml /openapi.json get /v1/sessions/{session_id}/threads/{thread_id}/stream openapi: 3.1.0 info: title: Checkfu API version: '2026-08-27' description: >- Authentication is declared per operation: API-key, runtime, or connector bearer; Automation signature; or credential-free pairing redemption. Every general Checkfu REST request requires the dated `Checkfu-Version` header (one of: 2026-08-27); the three MCP JSON-RPC transports use `MCP-Protocol-Version`, A2A uses `A2A-Version`, and the provider OAuth callback carries neither Checkfu header. API keys resolve one Workspace without a request selector; authenticated responses identify it with `Checkfu-Workspace-Id`. servers: - url: https://api.checkfu.com security: - bearerAuth: [] tags: - name: organizations - name: sourceRepositories - name: tenants - name: workspaces - name: principals - name: principalGroups - name: principalAccessCredentials - name: apiKeys - name: agents - name: harnesses - name: harnessRuntime - name: sandboxProfiles - name: computerProfiles - name: permissionAssignments - name: actionPolicies - name: files - name: memoryStores - name: dreams - name: modelCredentials - name: modelRoutingProfiles - name: blueprintInstallations - name: toolSources - name: skills - name: skillSources - name: agentSources - name: skillProposals - name: instructionProposals - name: catalog - name: concepts - name: support - name: connections - name: connectionVaults - name: connectionAssignments - name: connectedRuntimes - name: projects - name: collaboration - name: automationGraphs - name: automations - name: actionApprovals - name: standingApprovals - name: usage - name: models - name: outcomes - name: budgets - name: billing - name: sessions - name: audit - name: sessionExports - name: runs - name: runnerPools - name: transcripts - name: sessionWatches - name: webhookEndpoints - name: integrationGateway - name: agentDeployments - name: workEnvironments - name: computers - name: computerScreens - name: computerBrowserObservations - name: computerBrowserActions - name: environments - name: vaults - name: apiMcp - name: a2a paths: /v1/sessions/{session_id}/threads/{thread_id}/stream: get: tags: - sessions summary: Stream a Session thread's events (SSE) description: >- Resumable SSE for one thread's EventEnvelope history. A primary thread receives the condensed Session projection and a child receives its complete history; optional agent.message and agent.thinking previews are live-only and thread-local. Checkfu support posture: alpha; hosted. Required evidence journey: session-threads. Deployment-specific readiness and the latest proven release are available from GET /v1/support/capabilities. operationId: sessions.streamThreadEvents parameters: - name: session_id in: path schema: $ref: '#/components/schemas/SessionId' required: true - name: thread_id in: path schema: $ref: '#/components/schemas/SessionThreadId' required: true - name: page in: query required: false schema: type: string pattern: ^c1_[0-9a-z]+$ maxLength: 14 - name: event_deltas in: query required: false schema: type: array maxItems: 2 items: type: string enum: - agent.message - agent.thinking - name: live_ready in: query required: false schema: type: string enum: - '1' - name: last-event-id in: header required: false schema: type: string pattern: ^[0-9]+$ maxLength: 16 - name: checkfu-version in: header schema: type: string enum: - '2026-08-27' required: true responses: '200': description: text/event-stream of one thread's event envelopes content: text/event-stream: schema: type: string '400': description: Typed Checkfu wire error content: application/json: schema: type: object required: - error properties: error: type: object properties: type: type: string enum: - validation.malformed message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#validation-malformed description: >- Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false additionalProperties: false '401': description: Typed Checkfu wire error content: application/json: schema: type: object required: - error properties: error: type: object required: - type - message - more properties: type: type: string enum: - auth.invalid_key message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#auth-invalid-key description: >- Stable public documentation and remedy for this error type. additionalProperties: false additionalProperties: false '403': description: >- The organization, tenant, or workspace backing this key is administratively disabled. | Typed Checkfu wire error content: application/json: schema: anyOf: - type: object required: - error properties: error: type: object properties: type: type: string enum: - auth.disabled_tenancy message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#auth-disabled-tenancy description: >- Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false additionalProperties: false - type: object required: - error properties: error: type: object properties: type: type: string enum: - policy.denied message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#policy-denied description: >- Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false additionalProperties: false '404': description: Typed Checkfu wire error content: application/json: schema: type: object required: - error properties: error: type: object properties: type: type: string enum: - validation.not_found message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#validation-not-found description: >- Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false additionalProperties: false '429': description: Typed Checkfu wire error headers: retry-after: description: >- Delay in seconds for rate limits or deployment quotas with a known release or UTC reset boundary required: false schema: type: integer minimum: 1 content: application/json: schema: type: object required: - error properties: error: type: object required: - type - message - more properties: type: type: string enum: - budget.exceeded message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#budget-exceeded description: >- Stable public documentation and remedy for this error type. additionalProperties: false additionalProperties: false '500': description: Typed Checkfu wire error content: application/json: schema: type: object required: - error properties: error: type: object properties: type: type: string enum: - runtime.internal message: type: string more: type: string enum: - >- https://docs.checkfu.com/reference/errors#runtime-internal description: >- Stable public documentation and remedy for this error type. required: - type - message - more additionalProperties: false additionalProperties: false security: - bearerAuth: [] components: schemas: SessionId: type: string allOf: - pattern: ^sess_[0-9a-f]{32}$ SessionThreadId: type: string allOf: - pattern: ^sthr_[0-9a-f]{32}$ securitySchemes: bearerAuth: type: http scheme: bearer ````