> ## 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. # List DeliveryScreen verdicts for a Session > List the DeliveryScreen's verdicts projected from one Session's event log, so the post-side Check gate's stopped items are listable exactly as an AdmissionFilter's filtered deliveries are — this is the endpoint that explains why an outbound agent message is not readable. Every gate is one gesture (D203): another agent evaluates, before the acting agent (an AdmissionFilter's Check), after it (a DeliveryScreen), or over its work (an OutcomeSpec). Each ScreenedSessionMessage carries the verdict, the bounded reason, the content digest correlating it to the adjacent withheld or delivered `agent.message`, a `withheld_reason` of `screen_block` or `screen_failed` when content was withheld, and the Check's routing and usage counters; structural facts and the screen's bounded verdict text only, never the judged message content. This projects the Session's event log rather than a separate index, so each request scans a bounded window of log positions and a window holding no verdicts returns an empty `data` with a non-null `next_page`: read until `next_page` is null, never until `data` is empty. Retention governs the source log — erased Sessions are not addressable, and any position whose content was crypto-shredded or never durably written under ZDR is reported in `unavailable` rather than silently omitted, so an empty page is never mistaken for a Session that was never screened. Checkfu support posture: alpha; hosted. Required evidence journey: session-turn. Deployment-specific readiness and the latest proven release are available from GET /v1/support/capabilities. ## OpenAPI ````yaml /openapi.json get /v1/sessions/{id}/screened-messages 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: 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: sessionHandoffs - name: sessionCapsules - name: sessionTrajectories - 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/{id}/screened-messages: get: tags: - sessions summary: List DeliveryScreen verdicts for a Session description: >- List the DeliveryScreen's verdicts projected from one Session's event log, so the post-side Check gate's stopped items are listable exactly as an AdmissionFilter's filtered deliveries are — this is the endpoint that explains why an outbound agent message is not readable. Every gate is one gesture (D203): another agent evaluates, before the acting agent (an AdmissionFilter's Check), after it (a DeliveryScreen), or over its work (an OutcomeSpec). Each ScreenedSessionMessage carries the verdict, the bounded reason, the content digest correlating it to the adjacent withheld or delivered `agent.message`, a `withheld_reason` of `screen_block` or `screen_failed` when content was withheld, and the Check's routing and usage counters; structural facts and the screen's bounded verdict text only, never the judged message content. This projects the Session's event log rather than a separate index, so each request scans a bounded window of log positions and a window holding no verdicts returns an empty `data` with a non-null `next_page`: read until `next_page` is null, never until `data` is empty. Retention governs the source log — erased Sessions are not addressable, and any position whose content was crypto-shredded or never durably written under ZDR is reported in `unavailable` rather than silently omitted, so an empty page is never mistaken for a Session that was never screened. Checkfu support posture: alpha; hosted. Required evidence journey: session-turn. Deployment-specific readiness and the latest proven release are available from GET /v1/support/capabilities. operationId: sessions.listScreenedMessages parameters: - name: id in: path schema: $ref: '#/components/schemas/SessionId' required: true - name: checkfu-version in: header schema: type: string enum: - '2026-08-27' required: true - name: limit in: query schema: type: integer minimum: 1 required: false - name: page in: query schema: type: string allOf: - pattern: ^c1_[0-9a-z]+$ required: false responses: '200': description: Success content: application/json: schema: type: object properties: data: type: array items: type: object properties: seq: type: integer allOf: - exclusiveMinimum: 0 event_id: $ref: '#/components/schemas/EventId' verdict: type: string enum: - pass - block reason: anyOf: - type: string allOf: - maxLength: 512 - type: 'null' content_digest: type: string allOf: - pattern: ^sha256:[0-9a-f]{64}$ route: anyOf: - $ref: '#/components/schemas/Objects_147' - type: 'null' usage: anyOf: - $ref: '#/components/schemas/Objects_65' - type: 'null' withheld_reason: anyOf: - type: string enum: - screen_block - screen_failed - type: 'null' subagent: anyOf: - $ref: '#/components/schemas/SubagentId' - type: 'null' created_at: type: string required: - seq - event_id - verdict - reason - content_digest - route - usage - withheld_reason - subagent - created_at additionalProperties: false unavailable: type: array items: $ref: '#/components/schemas/Objects_424' next_page: anyOf: - type: string - type: 'null' required: - data - next_page additionalProperties: false headers: checkfu-workspace-id: description: The Workspace resolved from the authenticated bearer credential. required: true schema: $ref: '#/components/schemas/WorkspaceId' '400': description: Typed Checkfu wire error content: application/json: schema: $ref: '#/components/schemas/ValidationMalformedError' '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. | Deployment governance or retention policy denied the request. 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 - $ref: '#/components/schemas/PolicyDeniedError' '404': description: >- The requested resource does not exist in the resolved deployment boundary. content: application/json: schema: $ref: '#/components/schemas/ValidationNotFoundError' '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: >- An unexpected internal failure occurred; the message contains an opaque incident reference. content: application/json: schema: $ref: '#/components/schemas/RuntimeInternalError' security: - bearerAuth: [] components: schemas: SessionId: type: string allOf: - pattern: ^sess_[0-9a-f]{32}$ EventId: type: string allOf: - pattern: ^evt_[0-9a-f]{32}$ Objects_147: type: object properties: model_routing_profile_key: type: string model: type: string tier: type: string reason: type: string access_source: anyOf: - $ref: '#/components/schemas/Objects_37' - type: object properties: kind: type: string enum: - platform_supply provider: type: string allOf: - pattern: ^[a-z0-9](?:[a-z0-9._-]{0,93})$ usage_entry_id: $ref: '#/components/schemas/UsageEntryId' supply_id: $ref: '#/components/schemas/PlatformSupplyId' credential_generation_id: $ref: '#/components/schemas/SupplyCredentialGenerationId' rate_card_id: $ref: '#/components/schemas/BillingRateCardId' rated_at: $ref: '#/components/schemas/PlatformModelRatedAt' required: - kind - provider - usage_entry_id - supply_id - credential_generation_id - rate_card_id - rated_at additionalProperties: false required: - model_routing_profile_key - model - tier - reason additionalProperties: false Objects_65: type: object properties: input_tokens: type: integer allOf: - minimum: 0 cached_input_tokens: type: integer allOf: - minimum: 0 cache_write_input_tokens: type: integer allOf: - minimum: 0 output_tokens: type: integer allOf: - minimum: 0 reasoning_output_tokens: type: integer allOf: - minimum: 0 total_tokens: type: integer allOf: - minimum: 0 required: - input_tokens - cached_input_tokens - cache_write_input_tokens - output_tokens - reasoning_output_tokens - total_tokens additionalProperties: false SubagentId: type: string allOf: - pattern: ^subg_[0-9a-f]{32}$ Objects_424: type: object properties: seq: type: integer allOf: - exclusiveMinimum: 0 content_class: anyOf: - $ref: '#/components/schemas/Union_349' - type: 'null' reason: type: string enum: - shredded - zdr structural_replay: type: string enum: - complete - incomplete replay_fact: anyOf: - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - state_neutral required: - version - seq - kind additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - user_message content_length: type: integer allOf: - minimum: 0 authored_by: anyOf: - $ref: '#/components/schemas/Union_314' - type: 'null' required: - version - seq - kind - content_length - authored_by additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - agent_message content_length: type: integer allOf: - minimum: 0 required: - version - seq - kind - content_length additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - system_message required: - version - seq - kind additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - user_custom_tool_result authored_by: $ref: '#/components/schemas/Union_314' session_thread_id: $ref: '#/components/schemas/SessionThreadId' required: - version - seq - kind - authored_by additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - user_tool_confirmation authored_by: $ref: '#/components/schemas/Union_314' required: - version - seq - kind - authored_by additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - user_question_answer question: $ref: '#/components/schemas/QuestionId' authored_by: $ref: '#/components/schemas/Union_314' required: - version - seq - kind - question - authored_by additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - run_requires_action run: $ref: '#/components/schemas/RunId' attempt: $ref: '#/components/schemas/RunAttemptId' action: anyOf: - type: object properties: kind: type: string enum: - custom_tool tool_use_id: type: string required: - kind - tool_use_id additionalProperties: false - type: object properties: kind: type: string enum: - action_approval approval: $ref: '#/components/schemas/ActionApprovalId' tool_use_id: type: string on_approve: type: object properties: kind: type: string enum: - custom_tool required: - kind additionalProperties: false required: - kind - approval additionalProperties: false - type: object properties: kind: type: string enum: - question question: $ref: '#/components/schemas/QuestionId' required: - kind - question additionalProperties: false - type: object properties: kind: type: string enum: - outcome_evaluation outcome: $ref: '#/components/schemas/OutcomeId' iteration: type: integer allOf: - minimum: 0 required: - kind - outcome - iteration additionalProperties: false cost: $ref: '#/components/schemas/Objects_143' required: - version - seq - kind - run - attempt - action - cost additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - run_failed run: $ref: '#/components/schemas/RunId' attempt: anyOf: - $ref: '#/components/schemas/RunAttemptId' - type: 'null' error_type: $ref: '#/components/schemas/Union_215' required: - version - seq - kind - run - attempt - error_type additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - run_attempt_requeued run: $ref: '#/components/schemas/RunId' attempt: $ref: '#/components/schemas/RunAttemptId' error_type: $ref: '#/components/schemas/Union_215' required: - version - seq - kind - run - attempt - error_type additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - approval_resolved approval: $ref: '#/components/schemas/ActionApprovalId' participant: anyOf: - $ref: '#/components/schemas/PrincipalId' - type: 'null' required: - version - seq - kind - approval - participant additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - user_define_outcome outcome: $ref: '#/components/schemas/OutcomeId' authored_by: $ref: '#/components/schemas/Union_314' max_iterations: type: integer allOf: - minimum: 1 maximum: 20 required: - version - seq - kind - outcome - authored_by - max_iterations additionalProperties: false - type: object properties: version: type: number enum: - 1 seq: type: integer allOf: - exclusiveMinimum: 0 kind: type: string enum: - outcome_evaluation_completed outcome: $ref: '#/components/schemas/OutcomeId' iteration: type: integer allOf: - minimum: 0 result: type: string enum: - satisfied - needs_revision - max_iterations_reached - failed - interrupted report_summary: anyOf: - $ref: '#/components/schemas/OutcomeReportSummaryCounts' - type: 'null' required: - version - seq - kind - outcome - iteration - result - report_summary additionalProperties: false prompt_integrity: anyOf: - type: object properties: analyzer_version: type: string enum: - unicode-17.0.0-uts39-r32-checkfu-1 disposition: $ref: '#/components/schemas/Union_304' required: - analyzer_version - disposition additionalProperties: false - type: 'null' required: - seq - content_class - reason additionalProperties: false WorkspaceId: type: string allOf: - pattern: ^wrkspc_[0-9a-f]{32}$ ValidationMalformedError: type: object 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 required: - error additionalProperties: false description: >- The request could not be decoded or violated a declared input constraint. PolicyDeniedError: type: object 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 required: - error additionalProperties: false description: Deployment governance or retention policy denied the request. ValidationNotFoundError: type: object 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 required: - error additionalProperties: false description: >- The requested resource does not exist in the resolved deployment boundary. RuntimeInternalError: type: object 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 required: - error additionalProperties: false description: >- An unexpected internal failure occurred; the message contains an opaque incident reference. Objects_37: type: object properties: kind: type: string enum: - workspace_credential provider: type: string allOf: - pattern: ^[a-z0-9](?:[a-z0-9._-]{0,93})$ model_credential_id: $ref: '#/components/schemas/ModelCredentialId' model_credential_generation_id: $ref: '#/components/schemas/ModelCredentialGenerationId' required: - kind - provider - model_credential_id - model_credential_generation_id additionalProperties: false UsageEntryId: type: string allOf: - pattern: ^use_[0-9a-f]{32}$ PlatformSupplyId: type: string allOf: - pattern: ^sup_[0-9a-f]{32}$ SupplyCredentialGenerationId: type: string allOf: - pattern: ^sgen_[0-9a-f]{32}$ BillingRateCardId: type: string allOf: - pattern: ^rate_[0-9a-f]{32}$ PlatformModelRatedAt: type: string allOf: - maxLength: 24 - pattern: ^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}Z$ description: >- A canonical UTC ISO-8601 model-rating instant with millisecond precision. Union_349: type: string enum: - message - thinking - tool_arguments - tool_result - artifact - checkpoint - file_body - memory_document - sandbox_state - wire_frame Union_314: anyOf: - $ref: '#/components/schemas/PrincipalId' - $ref: '#/components/schemas/ApiKeyId' - $ref: '#/components/schemas/AutomationId' - $ref: '#/components/schemas/AgentInstallationId' SessionThreadId: type: string allOf: - pattern: ^sthr_[0-9a-f]{32}$ QuestionId: type: string allOf: - pattern: ^qst_[0-9a-f]{32}$ RunId: type: string allOf: - pattern: ^run_[0-9a-f]{32}$ RunAttemptId: type: string allOf: - pattern: ^ratt_[0-9a-f]{32}$ ActionApprovalId: anyOf: - $ref: '#/components/schemas/NonBrowserActionApprovalId' - $ref: '#/components/schemas/BrowserActionApprovalId' description: >- an ActionApprovalId of the form approval_<32 hex chars> or bapproval_<32 hex chars> OutcomeId: type: string allOf: - pattern: ^outc_[0-9a-f]{32}$ Objects_143: type: object properties: tokens: type: integer allOf: - minimum: 0 tool_calls: type: integer allOf: - minimum: 0 active_ms: type: integer allOf: - minimum: 0 additionalProperties: false Union_215: type: string enum: - validation.malformed - validation.prompt_integrity_review_required - validation.not_found - validation.conflict - validation.idempotency_conflict - validation.idempotency_in_progress - validation.payload_too_large - validation.range_too_large - auth.invalid_key - auth.disabled_tenancy - policy.denied - budget.exceeded - model.no_eligible_model - model.credential_rejected - model.platform_supply_unavailable - model.platform_capacity_reached - billing.entitlement_unavailable - billing.usage_limit_reached - billing.payment_required - billing.seat_activation_unavailable - memory.not_found - memory.conflict - memory.read_only - memory.invalid_path - memory.backend_unavailable - memory.curation_failed - runtime.invalid_transition - runtime.primary_thread - runtime.checkpoint_expired - runtime.session_history_unavailable - runtime.harness_unavailable - runtime.harness_failed - runtime.runner_unavailable - runtime.lease_lost - runtime.start_timeout - runtime.provisioning_suspended - runtime.turn_deadline_exceeded - runtime.observation_gap - runtime.observation_conflict - runtime.attestation_invalid - runtime.harness_incompatible - runtime.internal PrincipalId: type: string allOf: - pattern: ^prin_[0-9a-f]{32}$ OutcomeReportSummaryCounts: type: object properties: status: type: string enum: - accepted - rejected output_count: type: integer allOf: - exclusiveMinimum: 0 - maximum: 32 accepted_count: type: integer allOf: - minimum: 0 required: - status - output_count - accepted_count additionalProperties: false Union_304: type: string enum: - accepted_normalization - preserved_original ModelCredentialId: type: string allOf: - pattern: ^mcred_[0-9a-f]{32}$ ModelCredentialGenerationId: type: string allOf: - pattern: ^mcgen_[0-9a-f]{32}$ ApiKeyId: type: string allOf: - pattern: ^akey_[0-9a-f]{32}$ AutomationId: type: string allOf: - pattern: ^auto_[0-9a-f]{32}$ AgentInstallationId: type: string allOf: - pattern: ^aini_[0-9a-f]{32}$ NonBrowserActionApprovalId: type: string allOf: - pattern: ^approval_[0-9a-f]{32}$ BrowserActionApprovalId: type: string allOf: - pattern: ^bapproval_[0-9a-f]{32}$ securitySchemes: bearerAuth: type: http scheme: bearer ````