Session data structures

Session object

Returned by create, get, list, update, and archive endpoints.

Field	Type	Description
`id`	string	Session ID with the `sess_` prefix
`type`	string	Always `"session"`
`agent`	object	Agent snapshot used by this Session. See Session embedded agent for the field shape
`environment_id`	string	Environment ID used by this Session
`status`	string	Session lifecycle status: `rescheduling`, `running`, `idle`, or `terminated`. The `canceling` value in a Cancel endpoint response is a fixed acknowledgement value, not a persisted Session object status
`title`	string \| null	Session title
`metadata`	object	Session metadata
`environment_variables`	object	Session-level environment variables exported into the agent runtime as a map of string keys to string values (`{"NAME":"value"}`). Empty Sessions return `{}`. See Create a Session
`resources`	array of Session resource	File, GitHub, generic Git, or Memory Store resources attached to the Session
`vault_ids`	array of string	Vault IDs attached to the Session
`deployment_id`	string \| null	Deployment ID when the Session was created by a Deployment, otherwise `null`
`outcome_evaluations`	array	Outcome evaluation results. New Sessions return `[]`
`stats`	Session stats	Session statistics
`usage`	Session usage	Cumulative model, sandbox runtime, and total credits snapshot. Omitted when usage data is unavailable
`archived_at`	string \| null	Archive time, or `null` when not archived
`created_at`	string	Creation time
`updated_at`	string	Last update time

Session responses no longer include legacy fields such as agent_id, turn_status, or memory_store_ids.

Agent reference

agent in create requests can be either a string Agent ID or this object:

Field	Type	Required	Description
`id`	string	Yes	Agent ID with the `agent_` prefix
`type`	string	Yes (object form only)	Must be the literal `"agent"`. Missing or other values return 400 when the object form is used. The bare-string form (passing the Agent ID directly) skips this check
`version`	integer	No	Agent version to snapshot. Omit or pass `0` to use the latest active version

Session embedded agent

The agent returned inside a Session object is the Agent snapshot pinned to the Session, but several Agent fields are stripped before they are exposed: Publishing newer source Agent configuration does not replace this snapshot. Submitting agent fields through Update a session can change supported runtime fields locally for the Session without advancing its embedded agent.version; the linked guide also explains Skill version behavior.

created_at, updated_at — never included on the embedded Agent.
archived, archived_at — never included; the Session preserves access to the snapshot regardless of the source Agent's archive state.
metadata — Agent-level metadata is stripped; only Session-level metadata is exposed.
instructions — replaced by system.

See Multiagent roster element for the agent.multiagent.agents[] response structure and Session Thread object for the Agent structure returned in each thread.

`agent.model.effective_context_window`

Sessions return an additional response-only effective_context_window (int64, in tokens) inside agent.model. It is the runtime-resolved context window the Session will use for this Agent (after applying environment-level overrides). Absent or non-positive values are omitted; clients should treat the field as informational.

Session resource

resources[] is a union distinguished by type.

File resource

Field	Type	Required	Description
`id`	string	Response only	Resource ID
`type`	string	Yes	`"file"`
`file_id`	string	Yes	File ID with the `file_` prefix. The file must be ready
`mount_path`	string	No	Mount path in the container. Defaults to `/mnt/session/uploads/<file_id>` when omitted
`created_at`	string	Response only	Resource creation time
`updated_at`	string	Response only	Resource update time

GitHub repository resource

Field	Type	Required	Description
`id`	string	Response only	Resource ID
`type`	string	Yes	`"github_repository"`
`url`	string	Yes	Repository URL
`authorization_token`	string	No (write only)	GitHub token used to access a private repository or push. It is not returned in responses
`mount_path`	string	No	Clone target path in the container. Defaults from the repository name when omitted
`checkout`	object	No	Git checkout target, for example `{"type":"branch","name":"main"}`
`created_at`	string	Response only	Resource creation time
`updated_at`	string	Response only	Resource update time

Generic Git repository resource

Use this resource for GitLab, Gitee, Bitbucket, and other HTTP(S) Git providers.

Field	Type	Required	Description
`id`	string	Response only	Resource ID
`type`	string	Yes	`"git_repository"`
`url`	string	Yes	HTTP(S) clone URL. Public repositories need no username; authenticated repositories include it, e.g. `https://username@gitlab.com/group/repo.git`
`password`	string	No (write only)	Required together with a username for private repositories or push. Use the account password or the Access Token/PAT required by the provider. It is not returned in responses
`mount_path`	string	No	Clone target inside the container; derived from repository name when omitted
`checkout`	object	No	Git checkout target, e.g. `{"type":"branch","name":"main"}`
`created_at`	string	Response only	Resource creation time
`updated_at`	string	Response only	Resource update time

Memory Store resource

Field	Type	Required	Description
`type`	string	Yes	`"memory_store"`
`memory_store_id`	string	Yes	Memory Store ID with the `memstore_` prefix
`access`	string \| null	No	Optional access mode. Allowed values: `"read_write"`, `"read_only"`. Empty string or omitted means default (no override)
`instructions`	string \| null	No	Optional instructions stored on the Session resource. Maximum 4096 characters
`name`	string \| null	Response only	Current Memory Store name when available
`description`	string	Response only	Current Memory Store description when available
`mount_path`	string \| null	Response only	Current implementation returns `null` unless an existing resource snapshot contains a value

Memory Store resources do not include id, created_at, or updated_at fields.

Session stats

Field	Type	Description
`active_seconds`	number	Active processing time in seconds. New Sessions start at `0`
`duration_seconds`	number	Session duration in seconds. New Sessions start at `0`

Session usage

usage is the cumulative snapshot for a Session:

Field	Type	Description
`model_credits`	number	Credits accumulated from recorded model calls in the Session
`sandbox_runtime_credits`	number	Credits accumulated from billable cloud sandbox runtime used by the Session
`total_credits`	number	Total credits accumulated across all usage components

A Session without usage data omits the usage field. Each credits value is floored rather than rounded to at most 2 decimal places; for example, 7.6681 is returned as 7.66. JSON numbers do not preserve trailing zeroes, so 1.20 may be serialized as 1.2. Treat all three fields as one snapshot: overwrite local values by Session ID instead of adding them again on every query.

Multiagent roster element

In a Session response, ordinary Agent and self entries in agent.multiagent.agents[] return the corresponding Agent definitions with the fields below, excluding their own multiagent field. Advisor entries return only type and model, for example {"type":"advisor","model":"ultimate"}. See Advisor object.

Field	Type	Description
`type`	string	`"agent"` for a sibling Agent reference, or `"self"` for the coordinator itself
`id`	string	Agent ID. Present for `type = "agent"`; mirrors the coordinator's own ID when `type = "self"`
`version`	integer	Pinned Agent version. Present for `type = "agent"`
`name`	string	Hydrated Agent name
`description`	string \| null	Hydrated Agent description
`system`	string	Hydrated Agent system prompt (replaces `instructions`)
`model`	string \| object	Same shape as on the embedded Agent, including `effective_context_window` when set
Other Agent fields	varies	Tools, MCP servers, skills, and other Agent fields, with the same field stripping rules as the embedded Agent

If a referenced Agent definition cannot be retrieved (for example, its version no longer exists), the original reference is returned unchanged.

Event object

Events returned by send, list, and stream endpoints are event-specific JSON objects. Public event responses expose only the documented public fields for each event type.

Field	Type	Description
`id`	string	Event ID with the `evt_` prefix
`type`	string	Event type
`processed_at`	string	Present when the event has been processed. Many agent-generated events omit this field.

Depending on type, an event may also include fields such as content, input, name, tool_use_id, mcp_tool_use_id, custom_tool_use_id, result, deny_message, rubric, outcome_id, session_thread_id, stop_reason, error, usage, or model_usage.

Client event request types

POST /api/v1/cloud/sessions/{session_id}/events accepts exactly these client-sent event types:

Type	Required fields	Notes
`user.message`	`content`	`content` must be a non-empty array of content blocks
`user.interrupt`	none	`session_thread_id` is optional and is echoed as `null` when omitted
`user.tool_confirmation`	`tool_use_id`, `result`	`result` must be `allow` or `deny`; `deny_message` is optional
`user.tool_result`	`tool_use_id`	Use this to return a built-in tool result from a self-hosted worker. `content` is optional; when present, it must be an array of content blocks. `is_error` is optional
`user.custom_tool_result`	`custom_tool_use_id`	`content` is optional; when present, it must be an array of content blocks. `is_error` is optional
`user.define_outcome`	`description`, `rubric`	`rubric` is an object such as `{"type":"text","content":"..."}` or `{"type":"file","file_id":"file_..."}`; `max_iterations` is optional
`system.message`	`content`	`content` must be a non-empty array of text content blocks; the event must follow a user/tool result event

Message content blocks

events[].type identifies the event, content[].type identifies the content block, and an image's source.type identifies its source.

Event	Accepted `content[].type`	`content` requirements
`user.message`	`text`, `image`	Required, non-empty array; text and images may be mixed
`system.message`	`text`	Required, non-empty array
`user.tool_result`, `user.custom_tool_result`	`text`, `image`, `document`, `search_result`	Optional; when supplied, must be an array, which may be empty

User messages

All fields below are required. Use only the fields for the selected block type.

`content[].type`	Fields	Description
`text`	`type`, `text`	`text` must be a non-empty, non-whitespace string
`image`	`type`, `source`	`source` is one of the three formats below

All image source fields are strings:

`source.type`	Required fields	Description
`base64`	`type`, `media_type`, `data`	`media_type` is `image/png`, `image/jpeg`, `image/webp`, or `image/gif`; `data` is raw Base64, with optional trailing `=` padding and no Data URL prefix
`url`	`type`, `url`	External HTTPS image URL readable by the model service; private, loopback, and other restricted destinations are rejected
`file`	`type`, `file_id`	Image File ID from Upload file, readable by the current identity with status `ready`; supports PNG, JPEG, WebP, and GIF

Image limits:

Each user.message accepts at most 100 image blocks. Use a Session model that supports image input.
Each Base64 value is limited to 10 MiB (10,485,760 bytes) of encoded text, with width and height each at most 8000 pixels. Use a File source when the encoded length exceeds the limit.
Base64 and File images may be resized or compressed; URL images are fetched by the downstream model service.

User message examples

Each example is a single event object to place in the events array. Text:

{
  "type": "user.message",
  "content": [{"type": "text", "text": "Hello"}]
}

Base64 image:

{
  "type": "user.message",
  "content": [{"type": "image", "source": {"type": "base64", "media_type": "image/png", "data": "<raw Base64 image data>"}}]
}

URL image:

{
  "type": "user.message",
  "content": [{"type": "image", "source": {"type": "url", "url": "https://example.com/image.png"}}]
}

File image:

{
  "type": "user.message",
  "content": [{"type": "image", "source": {"type": "file", "file_id": "file_..."}}]
}

See Send events for the endpoint.

Public event types

List and stream endpoints can expose these event types: user.message, user.interrupt, user.tool_confirmation, user.custom_tool_result, user.define_outcome, user.tool_result, system.message, agent.custom_tool_use, agent.mcp_tool_result, agent.mcp_tool_use, agent.message, agent.thinking, agent.thread_context_compacted, agent.thread_message_received, agent.thread_message_sent, agent.tool_result, agent.tool_use, session.deleted, session.error, session.status_idle, session.status_rescheduled, session.status_running, session.status_terminated, session.thread_created, session.thread_status_idle, session.thread_status_rescheduled, session.thread_status_running, session.thread_status_terminated, session.updated, span.model_request_start, span.model_request_end, span.outcome_evaluation_start, span.outcome_evaluation_ongoing, and span.outcome_evaluation_end.

`session.updated` event

A successful Session update emits session.updated. The event always contains id, type, and processed_at. Depending on the request, it can additionally contain these fields:

Field	Type	Description
`title`	string \| null	Included when the request supplied `title`
`metadata`	object	Included when the resulting metadata object is non-empty and the request supplied `metadata`
`agent`	object	Updated embedded runtime snapshot, included after runtime configuration is changed through Update a session

An update that changes only environment_variables emits only the fixed fields. Environment-variable names and values are never included in this event.

`session.error` event

session.error reports an error during Session execution. The event contains id, type, processed_at, and error. The error object has these fields:

Field	Type	Description
`type`	string	Error category. Clients should handle `unknown_error` and future types
`message`	string	Human-readable error description
`retry_status`	object	Retry state. Its `type` is `retrying`, `exhausted`, or `terminal`
`qoder_error_code`	string	Optional diagnostic code. Clients must not use it to decide whether to retry

retry_status.type has these meanings:

Value	Description
`retrying`	The service is retrying automatically; the client should continue waiting
`exhausted`	The retry count or recovery window has been exhausted, or a non-retryable error failed immediately. No further automatic recovery is scheduled for this turn. Wait for subsequent status events before deciding whether to send a new message
`terminal`	The error is not recoverable and will not be retried automatically. Use subsequent Session/Thread status events to determine the final state

Advisor events

Advisor lifecycle events have agent_name: "qoder.advisor". Use session_thread_id to identify each consultation.

Event	Where to read it	Key fields
`agent.thread_message_received`	Main thread event stream	`from_session_thread_id` identifies the consultation thread, `from_agent_name` is `qoder.advisor`, and `content` contains the advice
`agent.thread_message_sent`	Advisor Thread event stream	`to_session_thread_id` and `to_agent_name` identify the main thread; `content` contains the advice
`session.error`	Advisor Thread event stream	`error` contains the cause and retry status; see session.error event
`session.thread_status_idle`	Session event stream	`stop_reason.type` is `end_turn` when the consultation ends (including interruption), or `retries_exhausted` on failure. See the thread's `session.error` for the cause

Example of the main thread receiving advice:

{
  "id": "evt_advisor_received",
  "type": "agent.thread_message_received",
  "processed_at": "2026-09-09T08:00:05Z",
  "from_session_thread_id": "sthr_advisor_call",
  "from_agent_name": "qoder.advisor",
  "content": [{"type": "text", "text": "Migrate through a canary rollout and verify the rollback steps."}]
}

A failed consultation does not stop the main Agent's task or produce an advice message. Read error details through the Thread events endpoint.

Event delta stream frames

A buffered event is a complete public Event object emitted after generation finishes and recorded in Session event history. It is the authoritative result. event_start and event_delta are stream-only SSE payloads used for incremental output. They are not public Event objects and do not appear in event list/history responses. Their JSON payloads have no top-level id or processed_at; the SSE id: field carries the ID of the event being streamed and can be used with Last-Event-ID.

Event start frame

An event_start frame identifies the public event whose incremental output has begun.

Field	Type	Description
`type`	string	Always `"event_start"`
`event`	object	Streamed event reference

The event object has these fields:

Field	Type	Description
`id`	string	Event ID with the `evt_` prefix. The SSE `id:`, related deltas, and buffered event use this same ID.
`type`	string	`"agent.message"` or `"agent.thinking"`

An agent.message start is followed by text event_delta frames. An agent.thinking start is start-only: no delta follows, and the buffered agent.thinking event with the same ID marks the end of that thinking phase when one is emitted.

{
  "type": "event_start",
  "event": {
    "id": "evt_00jjujk9fbnr4wkj2gh8",
    "type": "agent.message"
  }
}

Event delta frame

An event_delta frame appends text to an incrementally streamed agent.message.

Field	Type	Description
`type`	string	Always `"event_delta"`
`event_id`	string	ID from the matching `event_start.event.id` and SSE `id:` field
`delta`	object	Content delta

The delta object has these fields:

Field	Type	Description
`type`	string	Always `"content_delta"`
`index`	integer	Zero-based index of the content block being updated
`content`	object	Text fragment with `type: "text"` and a `text` string

{
  "type": "event_delta",
  "event_id": "evt_00jjujk9fbnr4wkj2gh8",
  "delta": {
    "type": "content_delta",
    "index": 0,
    "content": {
      "type": "text",
      "text": "Hello"
    }
  }
}

Model request span events

span.model_request_start marks the beginning of one model request.

Field	Type	Description
`id`	string	Event ID with the `evt_` prefix
`processed_at`	string	RFC 3339 timestamp
`type`	string	Always `"span.model_request_start"`

span.model_request_end marks completion of that model request and includes model_usage when credits are available for the call. model_usage.credits is floored to at most 2 decimal places.

Field	Type	Description
`id`	string	Event ID with the `evt_` prefix
`is_error`	boolean	Whether the model request ended with an error or cancellation
`model_request_start_id`	string	ID of the corresponding `span.model_request_start` event
`model_usage`	object	Optional usage for this model call. Omitted when credits are unavailable
`processed_at`	string	RFC 3339 timestamp
`type`	string	Always `"span.model_request_end"`

model_usage contains only:

Field	Type	Description
`credits`	number	Credits consumed by this model call. The value may be `0` and is floored to at most 2 decimal places

Session Thread object

In managed-agent scenarios, each thread within a Session is represented by this structure.

Field	Type	Description
`id`	string	Thread ID with the `sthr_` prefix
`type`	string	Always `"session_thread"`
`session_id`	string	Owning Session ID
`parent_thread_id`	string \| null	Parent thread ID. `null` for the coordinator thread
`agent`	object	An ordinary thread uses the Session embedded agent shape with `multiagent` removed; an Advisor Thread uses `{"type":"advisor","model":"..."}`
`status`	string	Thread lifecycle status: `running`, `idle`, `rescheduling`, or `terminated`
`stats`	object \| null	Thread statistics. Current implementation returns `null`
`archived_at`	string \| null	Archive time, or `null` when not archived
`created_at`	string	Creation time
`updated_at`	string	Last update time

Thread responses no longer include legacy fields such as agent_id, agent_version, name, role, stop_reason, created_by_tool_use_id, or usage.

​Session object

​Agent reference

​Session embedded agent

​agent.model.effective_context_window

​Session resource

​File resource

​GitHub repository resource

​Generic Git repository resource

​Memory Store resource

​Session stats

​Session usage

​Multiagent roster element

​Event object

​Client event request types

​Message content blocks

​User messages

​User message examples

​Public event types

​session.updated event

​session.error event

​Advisor events

​Event delta stream frames

​Event start frame

​Event delta frame

​Model request span events

​Session Thread object