> ## 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. # Get a Session's context ledger > Reads the Session's context ledger: the admitted definition version, `current_context_tokens` (which follows compaction resets), never-decreasing `cumulative_tokens`, the loaded tool and skill capabilities by reference, every compaction, and each platform-authored condensation with the `through_sequence` it covered. It answers what is loaded and what it has cost, rather than what happened, and is derived from the authoritative event ledger on every read. It carries no prompts, messages, or argument content, so it is shareable where a transcript is not. 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}/ledger 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/{id}/ledger: get: tags: - sessions summary: Get a Session's context ledger description: >- Reads the Session's context ledger: the admitted definition version, `current_context_tokens` (which follows compaction resets), never-decreasing `cumulative_tokens`, the loaded tool and skill capabilities by reference, every compaction, and each platform-authored condensation with the `through_sequence` it covered. It answers what is loaded and what it has cost, rather than what happened, and is derived from the authoritative event ledger on every read. It carries no prompts, messages, or argument content, so it is shareable where a transcript is not. 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.getSessionLedger 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 responses: '200': description: Success content: application/json: schema: type: object properties: session_id: $ref: '#/components/schemas/SessionId' current_definition_version: anyOf: - type: integer allOf: - exclusiveMinimum: 0 - type: 'null' current_context_tokens: type: integer allOf: - minimum: 0 cumulative_tokens: type: integer allOf: - minimum: 0 loaded_capabilities: type: array items: $ref: '#/components/schemas/Objects_163' compactions: type: array items: type: object properties: event_id: $ref: '#/components/schemas/EventId' seq: type: integer allOf: - exclusiveMinimum: 0 strategy: $ref: '#/components/schemas/Union_66' tokens_before: type: integer allOf: - minimum: 0 tokens_after: type: integer allOf: - minimum: 0 created_at: type: string required: - event_id - seq - strategy - tokens_before - tokens_after - created_at additionalProperties: false condensations: type: array items: type: object properties: event_id: $ref: '#/components/schemas/EventId' seq: type: integer allOf: - exclusiveMinimum: 0 through_sequence: type: integer allOf: - exclusiveMinimum: 0 condensed_user_messages: type: integer allOf: - minimum: 0 condensed_agent_messages: type: integer allOf: - minimum: 0 created_at: type: string required: - event_id - seq - through_sequence - condensed_user_messages - condensed_agent_messages - created_at additionalProperties: false last_event_seq: type: integer allOf: - minimum: 0 required: - session_id - current_definition_version - current_context_tokens - cumulative_tokens - loaded_capabilities - compactions - last_event_seq 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: 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. | 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: $ref: '#/components/schemas/RuntimeInternalError' security: - bearerAuth: [] components: schemas: SessionId: type: string allOf: - pattern: ^sess_[0-9a-f]{32}$ Objects_163: type: object properties: kind: type: string enum: - tool - skill ref: type: string allOf: - minLength: 1 - maxLength: 512 required: - kind - ref additionalProperties: false EventId: type: string allOf: - pattern: ^evt_[0-9a-f]{32}$ Union_66: type: string enum: - native - platform_summarize - truncate WorkspaceId: type: string allOf: - pattern: ^wrkspc_[0-9a-f]{32}$ 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. securitySchemes: bearerAuth: type: http scheme: bearer ````