openclaw/docs/concepts/session-tool.md

summary, read_when, title

summary	read_when	title
Agent tools for cross-session status, recall, messaging, and sub-agent orchestration	You want to understand what session tools the agent has You want to configure cross-session access or sub-agent spawning You want to inspect spawned sub-agent status	Session tools

OpenClaw gives agents tools to work across sessions, inspect status, and orchestrate sub-agents.

Available tools

Tool	What it does
sessions_list	List sessions with optional filters (kind, label, agent, archive, preview)
sessions_history	Read the transcript of a specific session
sessions_send	Send a message to another session and optionally wait
sessions_spawn	Spawn an isolated sub-agent session for background work
sessions_yield	End the current turn and wait for follow-up sub-agent results
subagents	List spawned sub-agent status for this session
session_status	Show a /status-style card and optionally set a per-session model override

These tools are still subject to the active tool profile and allow/deny policy. tools.profile: "coding" includes the full session orchestration set, including sessions_spawn, sessions_yield, and subagents. tools.profile: "messaging" includes cross-session messaging tools (sessions_list, sessions_history, sessions_send, session_status) but does not include sub-agent spawning. To keep a messaging profile and still allow native delegation, add:

{
  tools: {
    profile: "messaging",
    alsoAllow: ["sessions_spawn", "sessions_yield", "subagents"],
  },
}

Group, provider, sandbox, and per-agent policies can still remove those tools after the profile stage. Use /tools from the affected session to inspect the effective tool list.

Listing and reading sessions

sessions_list returns sessions with their key, agentId, kind, channel, model, token counts, and timestamps. Filter by kinds (array; accepted values: main, group, cron, hook, node, other), exact label, exact agentId, search text, or recency (activeMinutes). Active sessions are returned by default; pass archived: true to inspect archived sessions instead. Rows include pinned and archived state. Set includeDerivedTitles, includeLastMessage, or messageLimit (capped at 20) when you need mailbox-style triage: a visibility-scoped derived title, a last-message preview snippet, or bounded recent messages on each row. Derived titles and previews are produced only for sessions the caller can already see under the configured session tool visibility policy, so unrelated sessions stay hidden. When visibility is restricted, sessions_list returns optional visibility metadata showing the effective mode and a warning that results may be scope-limited.

sessions_history fetches the conversation transcript for a specific session. By default, tool results are excluded; pass includeTools: true to see them. Use limit for the newest bounded tail. Pass offset: 0 when you need pagination metadata, then pass returned nextOffset values to page backward through older OpenClaw transcript windows without reading raw transcript files. Explicit offset pages do not merge external CLI fallback imports; use the default newest-tail view (no offset) when you need that merged display history.

The returned view is intentionally bounded and safety-filtered:

• assistant text is normalized before recall:
  • thinking tags are stripped
  • <relevant-memories> / <relevant_memories> scaffolding blocks are stripped
  • plain-text tool-call XML payload blocks such as <tool_call>...</tool_call>, <function_call>...</function_call>, <tool_calls>...</tool_calls>, and <function_calls>...</function_calls> are stripped, including truncated payloads that never close cleanly
  • downgraded tool-call/result scaffolding such as [Tool Call: ...], [Tool Result ...], and [Historical context ...] is stripped
  • leaked model control tokens such as <|assistant|>, other ASCII <|...|> tokens, and full-width <｜...｜> variants are stripped
  • malformed MiniMax tool-call XML such as <invoke ...> / </minimax:tool_call> is stripped
• credential/token-like text is redacted before it is returned
• long text blocks are truncated
• very large histories can drop older rows or replace an oversized row with [sessions_history omitted: message too large]
• the tool reports summary flags such as truncated, droppedMessages, contentTruncated, contentRedacted, bytes, and pagination metadata

Both tools accept either a session key (like "main") or a session ID from a previous list call.

If you need the exact raw transcript, inspect the scoped SQLite transcript rows instead of treating sessions_history as an unfiltered dump.

Sending cross-session messages

sessions_send delivers a message to another session and optionally waits for the response:

• Fire-and-forget: set timeoutSeconds: 0 to enqueue and return immediately.
• Wait for reply: set a timeout and get the response inline.

Thread-scoped chat sessions, such as keys ending in :thread:<id>, are not valid sessions_send targets. Use the parent channel session key for inter-agent coordination so tool-routed messages do not appear inside an active human-facing thread.

Messages and A2A follow-up replies are marked as inter-session data in the receiving prompt ([Inter-session message ... isUser=false]) and in transcript provenance. The receiving agent should treat them as tool-routed data, not as a direct end-user-authored instruction.

After the target responds, OpenClaw can run a reply-back loop where the agents alternate messages (up to session.agentToAgent.maxPingPongTurns, range 0-20, default 5). The target agent can reply REPLY_SKIP to stop early.

Status and orchestration helpers

session_status is the lightweight /status-equivalent tool for the current or another visible session. It reports usage, time, model/runtime state, and linked background-task context when present. Like /status, it can backfill sparse token/cache counters from the latest transcript usage entry, and model=default clears a per-session override. Use sessionKey="current" for the caller's current session; visible client labels such as openclaw-tui are not session keys.

When route metadata is available, session_status also includes a visible Route context JSON block and matching structured details fields. These fields disambiguate the session key from the route that is currently handling the live run:

• origin is where the session was created, or the provider inferred from a deliverable session-key prefix when older state lacks stored origin metadata.
• active is the current live-run route. It is only reported for the live or current session being handled now.
• deliveryContext is the persisted delivery route stored on the session, which OpenClaw can reuse for later delivery even when the active surface differs.

Session state changes

OpenClaw keeps a best-effort signal log for selected session state changes: direct human messages to child sessions, child-run completion or failure, child creation, goal changes, and compaction. Cancelled and timed-out child runs are recorded as failures, with the specific outcome (cancelled, timeout, or error) preserved in the event payload. The log contains metadata and one-line summaries, never message content. Its stateVersion is the session's signal-log head, not a transactional change-data-capture version; the session-store mutation and signal append use separate storage, so a failed append is logged without failing the originating turn.

sessions_list includes stateVersion on rows with logged changes. session_status always returns stateVersion in structured details. Pass changesSince: <previousStateVersion> to retrieve up to 200 retained events after that version; this read does not acknowledge or advance parent notification cursors. A historyGap: true result means the requested version predates retained history, so refresh the whole session state instead of treating the response as an exact delta.

When another actor sends a direct human turn to a watched child or changes its goal, the parent receives a system notice telling it to call session_status with its last-seen version. Main-session parents are proactively woken. Nested sub-agent parents receive the notice on their next turn because heartbeat routing cannot target their queue directly. Completion announcements remain the owner for ordinary child-run completion delivery.

History is bounded to 30 days and 50,000 rows, while per-session heads remain monotonic after pruning. Notice delivery uses the gateway's in-memory system-event queue and assumes one gateway process owns delivery for the shared state database. Multiple gateways still share the durable log and changesSince reconciliation surface, but v1 does not push notices across processes. Parent notices require an agent-qualified parent session key; under session.scope="global" the shared global key is ambiguous across agents, so those parents get the durable log and changesSince but no proactive notices in v1.

sessions_yield intentionally ends the current turn so the next message can be the follow-up event you are waiting for. Use it after spawning sub-agents when you want completion results to arrive as the next message instead of building poll loops.

subagents is the visibility helper for already spawned OpenClaw sub-agents. It supports action: "list" to inspect active/recent runs.

Spawning sub-agents

sessions_spawn creates an isolated session for a background task by default. It is always non-blocking; it returns immediately with a runId and childSessionKey. Native sub-agent runs receive the delegated task in the child session's first visible [Subagent Task] message, while the system prompt carries only sub-agent runtime rules and routing context.

Key options:

• runtime: "subagent" (default) or "acp" for external harness agents.
• model and thinking overrides for the child session.
• thread: true to bind the spawn to a chat thread (Discord, Slack, etc.).
• sandbox: "require" to enforce sandboxing on the child.
• context: "fork" for native sub-agents when the child needs the current requester transcript; omit it or use context: "isolated" for a clean child. context: "fork" is only valid with runtime: "subagent". Thread-bound native sub-agents default to context: "fork" unless threadBindings.defaultSpawnContext says otherwise.

Default leaf sub-agents do not get session tools. When maxSpawnDepth >= 2, depth-1 orchestrator sub-agents additionally receive sessions_spawn, subagents, sessions_list, and sessions_history so they can manage their own children. Leaf runs still do not get recursive orchestration tools.

After completion, an announce step posts the result to the requester's channel. Completion delivery preserves bound thread/topic routing when available, and if the completion origin only identifies a channel, OpenClaw can still reuse the requester session's stored route (lastChannel / lastTo) for direct delivery.

For ACP-specific behavior, see ACP Agents.

Visibility

Session tools are scoped to limit what the agent can see:

Level	Scope
self	Only the current session
tree	Current session + spawned sub-agents
agent	All sessions for this agent
all	All sessions (cross-agent if configured)

Default is tree. Sandboxed sessions are clamped to tree regardless of config.

Further reading

• Session Management: routing, lifecycle, maintenance
• Sub-agents: child-session lifecycle and delivery
• ACP Agents: external harness spawning
• Multi-agent: multi-agent architecture
• Gateway Configuration: session tool config knobs

Related

• Session management
• Session pruning