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POST
Edit a message and rewind

Authorizations

Authorization
string
header
required

Your Reason API key from Settings > API. New keys use reason_; legacy ara_ keys remain accepted. Keys are capability-scoped: run, mcp:read, mcp:write, secrets:read, secrets:write, sessions:read, sessions:debug, knowledge:read, memory:read, memory:write, skills:read, skills:write, repos:read, repos:write, reviews:read, reviews:write, deployment:read, analytics:read, org:read, org:write, attachments:read, attachments:write, guardrails:read, guardrails:write, network:read, network:write, automations:read, automations:write, agent_auth:read. network:read and network:write are opt-in, excluded from default keys. network:read reads the saved workspace network policy; network:write replaces custom allowed hosts and requires a current organization owner/admin. Legacy project PATCH requests containing network_allowed_hosts also require network:write plus their existing run scope and project management permission; saved project hosts do not affect current session egress. Only owners/admins can mint or manage keys with network:write; keys cannot grant themselves more authority. See /docs/network-policies for replacement semantics and runtime applicability. mcp:write manages MCP server configuration only; it does not authorize remote MCP-tool execution. sessions:read reads sessions, including the assistant, reasoning and tool activity in their events. sessions:debug is privileged: only for organization owners/admins, it expands session events to the full diagnostic projection (diagnostic event kinds, status text and raw event metadata).

Path Parameters

orgId
string
required

Organization id or slug. Resolve it with GET /v3/self.

sessionId
string
required

The session id, returned as session_id by createSession and listSessions.

Body

application/json
content
string
required

The edited message. It replaces that message, and the conversation after it is set aside.

message_id
string

The follow-up to rewind to, by its id from listSessionMessages. Give this or client_message_id.

client_message_id
string

The message to rewind to, by the client_message_id it was sent with. This also names an opening prompt that was created with one; listSessionMessages does not list opening prompts.

Maximum string length: 160
request_id
string<uuid>

A caller-chosen id for this rewind, so a retried request returns the first rewind (deduplicated true) instead of rewinding twice. Omitted, every request rewinds.

Pattern: ^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$

Response

The rewind started.

ok
boolean
required

Always true on success.

session_id
string
required

The Session that runs again from the edited message.

deduplicated
boolean
required

True when this request_id was already applied and the first rewind is returned instead of starting another.