--- title: "Changes to Create an agent session" method: POST path: "/agents/sessions" --- # Changes to Create an agent session `POST /agents/sessions` > Every recorded change to this operation, newest first. ## Timeline Changed in 11 of 88 revisions. - **2026-10-29** `0a26f104d35f`: 7 info - **2026-10-28** `81bec64c97ee`: 7 info - **2026-10-23** `edf54d38a1a0`: 6 breaking, 8 info - **2026-10-16** `909d15009c82`: 1 info - **2026-10-16** `d9e93345b02a`: 7 warning - **2026-10-08** `93176c92c17d`: 1 breaking, 10 warning, 1 info - **2026-10-08** `cd5f51b7675c`: 1 info - **2026-10-08** `a95c419c9257`: 7 info - **2026-10-06** `2605da219e32`: 5 warning - **2026-10-06** `81031e5704b1`: 1 info - **2026-10-05** `7f654af7f94f`: 1 info ## Changes - **2026-10-29** `0a26f104d35f`: 7 info - added the new optional request property `agent/experimental` - added the optional property `agent/experimental` to the response with the `201` status (media type: application/json) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionCreated]/session/agent/experimental` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionFailed]/session/agent/experimental` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionIdle]/session/agent/experimental` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionInProgress]/session/agent/experimental` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionRequiresAction]/session/agent/experimental` to the response with the `201` status (media type: text/event-stream) - **2026-10-28** `81bec64c97ee`: 7 info - added the new optional request property `agent/compaction` - added the optional property `agent/compaction` to the response with the `201` status (media type: application/json) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionCreated]/session/agent/compaction` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionFailed]/session/agent/compaction` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionIdle]/session/agent/compaction` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionInProgress]/session/agent/compaction` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionRequiresAction]/session/agent/compaction` to the response with the `201` status (media type: text/event-stream) - **2026-10-23** `edf54d38a1a0`: 6 breaking, 8 info - added `#/components/schemas/AgentToolResourceAutomations` to the `agent/tools/items/` response property `oneOf` list for the response status `201` (media type: application/json) - added `#/components/schemas/AgentToolResourceAutomations` to the `oneOf[#/components/schemas/SessionEventAgentSessionCreated]/session/agent/tools/items/` response property `oneOf` list for the response status `201` (media type: text/event-stream) - added `#/components/schemas/AgentToolResourceAutomations` to the `oneOf[#/components/schemas/SessionEventAgentSessionFailed]/session/agent/tools/items/` response property `oneOf` list for the response status `201` (media type: text/event-stream) - added `#/components/schemas/AgentToolResourceAutomations` to the `oneOf[#/components/schemas/SessionEventAgentSessionIdle]/session/agent/tools/items/` response property `oneOf` list for the response status `201` (media type: text/event-stream) - added `#/components/schemas/AgentToolResourceAutomations` to the `oneOf[#/components/schemas/SessionEventAgentSessionInProgress]/session/agent/tools/items/` response property `oneOf` list for the response status `201` (media type: text/event-stream) - added `#/components/schemas/AgentToolResourceAutomations` to the `oneOf[#/components/schemas/SessionEventAgentSessionRequiresAction]/session/agent/tools/items/` response property `oneOf` list for the response status `201` (media type: text/event-stream) - added `automations` discriminator mapping keys to the `agent/tools/items/` request property - added `#/components/schemas/AgentToolConfigParamAutomations` to the `agent/tools/items/` request property `oneOf` list - added `automations` discriminator mapping keys to the `agent/tools/items/` response property for the response status `201` (media type: application/json) - added `automations` discriminator mapping keys to the `oneOf[#/components/schemas/SessionEventAgentSessionCreated]/session/agent/tools/items/` response property for the response status `201` (media type: text/event-stream) - added `automations` discriminator mapping keys to the `oneOf[#/components/schemas/SessionEventAgentSessionFailed]/session/agent/tools/items/` response property for the response status `201` (media type: text/event-stream) - added `automations` discriminator mapping keys to the `oneOf[#/components/schemas/SessionEventAgentSessionIdle]/session/agent/tools/items/` response property for the response status `201` (media type: text/event-stream) - added `automations` discriminator mapping keys to the `oneOf[#/components/schemas/SessionEventAgentSessionInProgress]/session/agent/tools/items/` response property for the response status `201` (media type: text/event-stream) - added `automations` discriminator mapping keys to the `oneOf[#/components/schemas/SessionEventAgentSessionRequiresAction]/session/agent/tools/items/` response property for the response status `201` (media type: text/event-stream) - **2026-10-16** `909d15009c82`: 1 info - added the new `ultrafast` enum value to the request property `agent/service_tier/anyOf[#/components/schemas/ServiceTierParam]/` - **2026-10-16** `d9e93345b02a`: 7 warning - removed the request property `spend_control` - removed the optional property `oneOf[#/components/schemas/SessionEventAgentSessionCreated]/session/spend_control` from the response with the `201` status (media type: text/event-stream) - removed the optional property `oneOf[#/components/schemas/SessionEventAgentSessionFailed]/session/spend_control` from the response with the `201` status (media type: text/event-stream) - removed the optional property `oneOf[#/components/schemas/SessionEventAgentSessionIdle]/session/spend_control` from the response with the `201` status (media type: text/event-stream) - removed the optional property `oneOf[#/components/schemas/SessionEventAgentSessionInProgress]/session/spend_control` from the response with the `201` status (media type: text/event-stream) - removed the optional property `oneOf[#/components/schemas/SessionEventAgentSessionRequiresAction]/session/spend_control` from the response with the `201` status (media type: text/event-stream) - removed the optional property `spend_control` from the response with the `201` status (media type: application/json) - **2026-10-08** `93176c92c17d`: 1 breaking, 10 warning, 1 info - added `#/components/schemas/SessionEventAgentSessionEnvironmentSuspended, #/components/schemas/SessionEventAgentSessionEnvironmentExpired` to the response body `oneOf` list for the response status `201` - added the new `expired` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionEnvironmentConnected]/environment/status` response property for the response status `201` - added the new `expired` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionEnvironmentDisconnected]/environment/status` response property for the response status `201` - added the new `expired` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionEnvironmentFailed]/environment/status` response property for the response status `201` - added the new `expired` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionEnvironmentPending]/environment/status` response property for the response status `201` - added the new `expired` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionEnvironmentReady]/environment/status` response property for the response status `201` - added the new `suspended` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionEnvironmentConnected]/environment/status` response property for the response status `201` - added the new `suspended` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionEnvironmentDisconnected]/environment/status` response property for the response status `201` - added the new `suspended` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionEnvironmentFailed]/environment/status` response property for the response status `201` - added the new `suspended` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionEnvironmentPending]/environment/status` response property for the response status `201` - added the new `suspended` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionEnvironmentReady]/environment/status` response property for the response status `201` - added `agent.session.environment.suspended, agent.session.environment.expired` mapping keys to the response discriminator for the response status `201` - **2026-10-08** `cd5f51b7675c`: 1 info - added the new optional request property `environment/oneOf[#/components/schemas/EnvironmentParamOpenaiHosted]/environment_id` - **2026-10-08** `a95c419c9257`: 7 info - added the new optional request property `spend_control` - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionCreated]/session/spend_control` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionFailed]/session/spend_control` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionIdle]/session/spend_control` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionInProgress]/session/spend_control` to the response with the `201` status (media type: text/event-stream) - added the optional property `oneOf[#/components/schemas/SessionEventAgentSessionRequiresAction]/session/spend_control` to the response with the `201` status (media type: text/event-stream) - added the optional property `spend_control` to the response with the `201` status (media type: application/json) - **2026-10-06** `2605da219e32`: 5 warning - added the new `billing_not_active` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionTurnCancelled]/turn/error/anyOf[#/components/schemas/SessionTurnErrorResource]/code` response property for the response status `201` - added the new `billing_not_active` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionTurnCompleted]/turn/error/anyOf[#/components/schemas/SessionTurnErrorResource]/code` response property for the response status `201` - added the new `billing_not_active` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionTurnCreated]/turn/error/anyOf[#/components/schemas/SessionTurnErrorResource]/code` response property for the response status `201` - added the new `billing_not_active` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionTurnFailed]/turn/error/anyOf[#/components/schemas/SessionTurnErrorResource]/code` response property for the response status `201` - added the new `billing_not_active` enum value to the `oneOf[#/components/schemas/SessionEventAgentSessionTurnInProgress]/turn/error/anyOf[#/components/schemas/SessionTurnErrorResource]/code` response property for the response status `201` - **2026-10-06** `81031e5704b1`: 1 info - added the non-success response with the status `429` - **2026-10-05** `7f654af7f94f`: 1 info - endpoint added --- [Operation](https://skmtc.dev/omnistack-sh/apis/openai-api/docs/agents/sessions/post.md) - [API](https://skmtc.dev/omnistack-sh/apis/openai-api.md) - [Page](https://skmtc.dev/omnistack-sh/apis/openai-api/changes/agents/sessions/post)