openclaw/docs/concepts/session-tool.md

---
summary: "Agent tools for cross-session status, recall, messaging, and sub-agent orchestration"
read_when:
  - 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 status or control spawned sub-agents
title: "Session Tools"
---

# 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, recency)                         |
| `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, steer, or kill spawned sub-agents for this session                    |
| `session_status`   | Show a `/status`-style card and optionally set a per-session model override |

## Listing and reading sessions

`sessions_list` returns sessions with their key, kind, channel, model, token
counts, and timestamps. Filter by kind (`main`, `group`, `cron`, `hook`,
`node`) or recency (`activeMinutes`).

`sessions_history` fetches the conversation transcript for a specific session.
By default, tool results are excluded -- pass `includeTools: true` to see them.
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`, and `bytes`

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

If you need the exact byte-for-byte transcript, inspect the transcript file on
disk instead of treating `sessions_history` as a raw 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.

After the target responds, OpenClaw can run a **reply-back loop** where the
agents alternate messages (up to 5 turns). 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.

`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 control-plane helper for already spawned OpenClaw
sub-agents. It supports:

- `action: "list"` to inspect active/recent runs
- `action: "steer"` to send follow-up guidance to a running child
- `action: "kill"` to stop one child or `all`

## Spawning sub-agents

`sessions_spawn` creates an isolated session for a background task. It is always
non-blocking -- it returns immediately with a `runId` and `childSessionKey`.

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.

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](/tools/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](/concepts/session) -- routing, lifecycle, maintenance
- [ACP Agents](/tools/acp-agents) -- external harness spawning
- [Multi-agent](/concepts/multi-agent) -- multi-agent architecture
- [Gateway Configuration](/gateway/configuration) -- session tool config knobs