bot/docs/concepts/session-tool.md

summary, read_when, title

summary	read_when	title
Agent session tools for listing sessions, fetching history, and sending cross-session messages	Adding or modifying session tools	Session Tools

Session Tools

Goal: small, hard-to-misuse tool set so agents can list sessions, fetch history, and send to another session.

Tool Names

• sessions_list
• sessions_history
• sessions_send
• sessions_spawn

Key Model

• Main direct chat bucket is always the literal key "main" (resolved to the current agent’s main key).
• Group chats use agent:<agentId>:<channel>:group:<id> or agent:<agentId>:<channel>:channel:<id> (pass the full key).
• Cron jobs use cron:<job.id>.
• Hooks use hook:<uuid> unless explicitly set.
• Node sessions use node-<nodeId> unless explicitly set.

global and unknown are reserved values and are never listed. If session.scope = "global", we alias it to main for all tools so callers never see global.

sessions_list

List sessions as an array of rows.

Parameters:

• kinds?: string[] filter: any of "main" | "group" | "cron" | "hook" | "node" | "other"
• limit?: number max rows (default: server default, clamp e.g. 200)
• activeMinutes?: number only sessions updated within N minutes
• messageLimit?: number 0 = no messages (default 0); >0 = include last N messages

Behavior:

• messageLimit > 0 fetches chat.history per session and includes the last N messages.
• Tool results are filtered out in list output; use sessions_history for tool messages.
• When running in a sandboxed agent session, session tools default to spawned-only visibility (see below).

Row shape (JSON):

• key: session key (string)
• kind: main | group | cron | hook | node | other
• channel: whatsapp | telegram | discord | signal | imessage | webchat | internal | unknown
• displayName (group display label if available)
• updatedAt (ms)
• sessionId
• model, contextTokens, totalTokens
• thinkingLevel, verboseLevel, systemSent, abortedLastRun
• sendPolicy (session override if set)
• lastChannel, lastTo
• deliveryContext (normalized { channel, to, accountId } when available)
• transcriptPath (best-effort path derived from store dir + sessionId)
• messages? (only when messageLimit > 0)

sessions_history

Fetch transcript for one session.

Parameters:

• sessionKey (required; accepts session key or sessionId from sessions_list)
• limit?: number max messages (server clamps)
• includeTools?: boolean (default false)

Behavior:

• includeTools=false filters role: "toolResult" messages.
• Returns messages array in the raw transcript format.
• When given a sessionId, HanzoBot resolves it to the corresponding session key (missing ids error).

sessions_send

Send a message into another session.

Parameters:

• sessionKey (required; accepts session key or sessionId from sessions_list)
• message (required)
• timeoutSeconds?: number (default >0; 0 = fire-and-forget)

Behavior:

• timeoutSeconds = 0: enqueue and return { runId, status: "accepted" }.
• timeoutSeconds > 0: wait up to N seconds for completion, then return { runId, status: "ok", reply }.
• If wait times out: { runId, status: "timeout", error }. Run continues; call sessions_history later.
• If the run fails: { runId, status: "error", error }.
• Announce delivery runs after the primary run completes and is best-effort; status: "ok" does not guarantee the announce was delivered.
• Waits via gateway agent.wait (server-side) so reconnects don't drop the wait.
• Agent-to-agent message context is injected for the primary run.
• Inter-session messages are persisted with message.provenance.kind = "inter_session" so transcript readers can distinguish routed agent instructions from external user input.
• After the primary run completes, HanzoBot runs a reply-back loop:
  • Round 2+ alternates between requester and target agents.
  • Reply exactly REPLY_SKIP to stop the ping‑pong.
  • Max turns is session.agentToAgent.maxPingPongTurns (0–5, default 5).
• Once the loop ends, HanzoBot runs the agent‑to‑agent announce step (target agent only):
  • Reply exactly ANNOUNCE_SKIP to stay silent.
  • Any other reply is sent to the target channel.
  • Announce step includes the original request + round‑1 reply + latest ping‑pong reply.

Channel Field

• For groups, channel is the channel recorded on the session entry.
• For direct chats, channel maps from lastChannel.
• For cron/hook/node, channel is internal.
• If missing, channel is unknown.

Security / Send Policy

Policy-based blocking by channel/chat type (not per session id).

{
  "session": {
    "sendPolicy": {
      "rules": [
        {
          "match": { "channel": "discord", "chatType": "group" },
          "action": "deny"
        }
      ],
      "default": "allow"
    }
  }
}

Runtime override (per session entry):

• sendPolicy: "allow" | "deny" (unset = inherit config)
• Settable via sessions.patch or owner-only /send on|off|inherit (standalone message).

Enforcement points:

• chat.send / agent (gateway)
• auto-reply delivery logic

sessions_spawn

Spawn a sub-agent run in an isolated session and announce the result back to the requester chat channel.

Parameters:

• task (required)
• label? (optional; used for logs/UI)
• agentId? (optional; spawn under another agent id if allowed)
• model? (optional; overrides the sub-agent model; invalid values error)
• thinking? (optional; overrides thinking level for the sub-agent run)
• runTimeoutSeconds? (defaults to agents.defaults.subagents.runTimeoutSeconds when set, otherwise 0; when set, aborts the sub-agent run after N seconds)
• thread? (default false; request thread-bound routing for this spawn when supported by the channel/plugin)
• mode? (run|session; defaults to run, but defaults to session when thread=true; mode="session" requires thread=true)
• cleanup? (delete|keep, default keep)
• sandbox? (inherit|require, default inherit; require rejects spawn unless the target child runtime is sandboxed)
• attachments? (optional array of inline files; subagent runtime only, ACP rejects). Each entry: { name, content, encoding?: "utf8" | "base64", mimeType? }. Files are materialized into the child workspace at .hanzo-bot/attachments/<uuid>/. Returns a receipt with sha256 per file.
• attachAs? (optional; { mountPath? } hint reserved for future mount implementations)

Allowlist:

• agents.list[].subagents.allowAgents: list of agent ids allowed via agentId (["*"] to allow any). Default: only the requester agent.
• Sandbox inheritance guard: if the requester session is sandboxed, sessions_spawn rejects targets that would run unsandboxed.

Discovery:

• Use agents_list to discover which agent ids are allowed for sessions_spawn.

Behavior:

• Starts a new agent:<agentId>:subagent:<uuid> session with deliver: false.
• Sub-agents default to the full tool set minus session tools (configurable via tools.subagents.tools).
• Sub-agents are not allowed to call sessions_spawn (no sub-agent → sub-agent spawning).
• Always non-blocking: returns { status: "accepted", runId, childSessionKey } immediately.
• With thread=true, channel plugins can bind delivery/routing to a thread target (Discord support is controlled by session.threadBindings.* and channels.discord.threadBindings.*).
• After completion, HanzoBot runs a sub-agent announce step and posts the result to the requester chat channel.
  • If the assistant final reply is empty, the latest toolResult from sub-agent history is included as Result.
• Reply exactly ANNOUNCE_SKIP during the announce step to stay silent.
• Announce replies are normalized to Status/Result/Notes; Status comes from runtime outcome (not model text).
• Sub-agent sessions are auto-archived after agents.defaults.subagents.archiveAfterMinutes (default: 60).
• Announce replies include a stats line (runtime, tokens, sessionKey/sessionId, transcript path, and optional cost).

Sandbox Session Visibility

Session tools can be scoped to reduce cross-session access.

Default behavior:

• tools.sessions.visibility defaults to tree (current session + spawned subagent sessions).
• For sandboxed sessions, agents.defaults.sandbox.sessionToolsVisibility can hard-clamp visibility.

Config:

{
  tools: {
    sessions: {
      // "self" | "tree" | "agent" | "all"
      // default: "tree"
      visibility: "tree",
    },
  },
  agents: {
    defaults: {
      sandbox: {
        // default: "spawned"
        sessionToolsVisibility: "spawned", // or "all"
      },
    },
  },
}

Notes:

• self: only the current session key.
• tree: current session + sessions spawned by the current session.
• agent: any session belonging to the current agent id.
• all: any session (cross-agent access still requires tools.agentToAgent).
• When a session is sandboxed and sessionToolsVisibility="spawned", HanzoBot clamps visibility to tree even if you set tools.sessions.visibility="all".