> ## Documentation Index > Fetch the complete documentation index at: https://arizeai-433a7140-roger-ci-skip-release-prs.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Patch Session > Update a persisted session's mutable fields. ## OpenAPI ````yaml patch /v1/agent_sessions/{session_id} openapi: 3.1.0 info: title: Arize-Phoenix REST API description: Schema for Arize-Phoenix REST API version: '1.0' servers: [] security: [] paths: /v1/agent_sessions/{session_id}: patch: tags: - chat summary: Patch Session description: Update a persisted session's mutable fields. operationId: patchAgentSession parameters: - name: session_id in: path required: true schema: type: string title: Session Id requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/PatchAgentSessionRequestBody' responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/PatchAgentSessionResponseBody' '400': content: text/plain: schema: type: string description: Bad Request '401': content: text/plain: schema: type: string description: Unauthorized '403': content: text/plain: schema: type: string description: Forbidden '404': content: text/plain: schema: type: string description: Not Found '409': description: >- The request conflicts with the session's current state; the body's ``code`` field says how. content: application/json: schema: $ref: '#/components/schemas/AgentSessionConflictError' '422': content: text/plain: schema: type: string description: Unprocessable Entity '507': content: text/plain: schema: type: string description: Insufficient Storage components: schemas: PatchAgentSessionRequestBody: properties: title: type: string maxLength: 100 title: Title description: New title for the session model: $ref: '#/components/schemas/AgentModelSelection' description: New model selection for the session type: object title: PatchAgentSessionRequestBody description: >- Fields to update on a persisted session. Omit a field to leave it unchanged. PatchAgentSessionResponseBody: properties: data: $ref: '#/components/schemas/AgentSessionData' type: object required: - data title: PatchAgentSessionResponseBody AgentSessionConflictError: properties: code: type: string enum: - agent_session_busy - agent_session_model_stale - agent_session_messages_stale - agent_session_tool_outputs_conflict - agent_session_already_compact - agent_session_compaction_conflict title: Code description: Machine-readable reason the request conflicted. message: anyOf: - type: string - type: 'null' title: Message description: Optional human-readable elaboration on the conflict. type: object required: - code title: AgentSessionConflictError description: >- Body of every HTTP 409 returned by the agent session routes. - ``agent_session_busy``: another turn holds the session's turn lock. - ``agent_session_model_stale``: the request asserted a model the session is no longer set to; refetch the session before retrying. - ``agent_session_messages_stale``: the send's ``lastMessageId`` no longer matches the persisted transcript — another client appended; refetch the transcript and retry. - ``agent_session_tool_outputs_conflict``: the submitted ``toolOutputs`` do not match the transcript's trailing assistant message (no trailing assistant message to continue, an unknown ``toolCallId``, or a tool-name mismatch). Unlike ``agent_session_messages_stale`` this is not a concurrent-writer race but an inconsistent request; fix the client rather than retrying. - ``agent_session_already_compact``: there are no complete turns to compact — either nothing new has finished since the transcript's latest checkpoint, or a concurrent request's checkpoint already covers them. Not retryable; the conversation is as compact as it can get. - ``agent_session_compaction_conflict``: the conversation changed while it was being compacted; retry. AgentModelSelection: oneOf: - $ref: '#/components/schemas/CustomProviderModelSelection' - $ref: '#/components/schemas/BuiltInProviderModelSelection' discriminator: propertyName: providerType mapping: builtin: $ref: '#/components/schemas/BuiltInProviderModelSelection' custom: $ref: '#/components/schemas/CustomProviderModelSelection' AgentSessionData: properties: id: type: string title: Id title: type: string title: Title created_at: type: string format: date-time title: Created At updated_at: type: string format: date-time title: Updated At is_ephemeral: type: boolean title: Is Ephemeral model: $ref: '#/components/schemas/AgentModelSelection' is_active: type: boolean title: Is Active description: >- Whether a response is currently streaming on this session, i.e. its lock has a live (non-stale) heartbeat. last_message_id: anyOf: - type: string - type: 'null' title: Last Message Id description: >- The message ID of the most recently persisted transcript message, or null for an empty transcript. type: object required: - id - title - created_at - updated_at - is_ephemeral - model - is_active title: AgentSessionData CustomProviderModelSelection: properties: providerType: type: string const: custom title: Providertype providerId: type: string title: Providerid modelName: type: string title: Modelname type: object required: - providerType - providerId - modelName title: CustomProviderModelSelection description: Chat against a stored custom provider record. BuiltInProviderModelSelection: properties: providerType: type: string const: builtin title: Providertype provider: $ref: '#/components/schemas/ModelProvider' modelName: type: string title: Modelname type: object required: - providerType - provider - modelName title: BuiltInProviderModelSelection description: |- Chat against a Phoenix built-in provider. Credentials and connection details (base URL, Azure endpoint, AWS region) are resolved from the secret store first and the process environment second. ModelProvider: type: string enum: - OPENAI - AZURE_OPENAI - ANTHROPIC - GOOGLE - DEEPSEEK - XAI - OLLAMA - AWS - CEREBRAS - FIREWORKS - GROQ - MOONSHOT - PERPLEXITY - TOGETHER title: ModelProvider ````