diff --git a/CHANGELOG.md b/CHANGELOG.md
index d882c0c83cb..d1efde75b9f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,10 @@ Docs: https://docs.openclaw.ai
 
 - **BREAKING:** non-loopback Control UI now requires explicit `gateway.controlUi.allowedOrigins` (full origins). Startup fails closed when missing unless `gateway.controlUi.dangerouslyAllowHostHeaderOriginFallback=true` is set to use Host-header origin fallback mode.
 
+### Changes
+
+- Subagents/Sessions: add `agents.defaults.subagents.runTimeoutSeconds` so `sessions_spawn` can inherit a configurable default timeout when the tool call omits `runTimeoutSeconds` (unset remains `0`, meaning no timeout). (#24594) Thanks @mitchmcalister.
+
 ### Fixes
 
 - Gateway/Browser control: load `src/browser/server.js` during browser-control startup so the control listener starts reliably when browser control is enabled. (#23974) Thanks @ieaves.
diff --git a/docs/concepts/session-tool.md b/docs/concepts/session-tool.md
index ebac95dbe55..bbd58d599ce 100644
--- a/docs/concepts/session-tool.md
+++ b/docs/concepts/session-tool.md
@@ -152,7 +152,7 @@ Parameters:
 - `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?` (default 0; when set, aborts the sub-agent run after N seconds)
+- `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`)
diff --git a/docs/gateway/configuration-reference.md b/docs/gateway/configuration-reference.md
index 8ff41036354..0b89a272d90 100644
--- a/docs/gateway/configuration-reference.md
+++ b/docs/gateway/configuration-reference.md
@@ -1683,6 +1683,7 @@ Notes:
       subagents: {
         model: "minimax/MiniMax-M2.1",
         maxConcurrent: 1,
+        runTimeoutSeconds: 900,
         archiveAfterMinutes: 60,
       },
     },
@@ -1691,6 +1692,7 @@ Notes:
 ```
 
 - `model`: default model for spawned sub-agents. If omitted, sub-agents inherit the caller's model.
+- `runTimeoutSeconds`: default timeout (seconds) for `sessions_spawn` when the tool call omits `runTimeoutSeconds`. `0` means no timeout.
 - Per-subagent tool policy: `tools.subagents.tools.allow` / `tools.subagents.tools.deny`.
 
 ---
diff --git a/docs/tools/index.md b/docs/tools/index.md
index 88b2ee6bccd..269b6856d03 100644
--- a/docs/tools/index.md
+++ b/docs/tools/index.md
@@ -478,6 +478,7 @@ Notes:
   - Supports one-shot mode (`mode: "run"`) and persistent thread-bound mode (`mode: "session"` with `thread: true`).
   - If `thread: true` and `mode` is omitted, mode defaults to `session`.
   - `mode: "session"` requires `thread: true`.
+  - If `runTimeoutSeconds` is omitted, OpenClaw uses `agents.defaults.subagents.runTimeoutSeconds` when set; otherwise timeout defaults to `0` (no timeout).
   - Discord thread-bound flows depend on `session.threadBindings.*` and `channels.discord.threadBindings.*`.
   - Reply format includes `Status`, `Result`, and compact stats.
   - `Result` is the assistant completion text; if missing, the latest `toolResult` is used as fallback.
diff --git a/docs/tools/subagents.md b/docs/tools/subagents.md
index 7334da1ec40..9542858c840 100644
--- a/docs/tools/subagents.md
+++ b/docs/tools/subagents.md
@@ -71,6 +71,7 @@ Use `sessions_spawn`:
 - Then runs an announce step and posts the announce reply to the requester chat channel
 - Default model: inherits the caller unless you set `agents.defaults.subagents.model` (or per-agent `agents.list[].subagents.model`); an explicit `sessions_spawn.model` still wins.
 - Default thinking: inherits the caller unless you set `agents.defaults.subagents.thinking` (or per-agent `agents.list[].subagents.thinking`); an explicit `sessions_spawn.thinking` still wins.
+- Default run timeout: if `sessions_spawn.runTimeoutSeconds` is omitted, OpenClaw uses `agents.defaults.subagents.runTimeoutSeconds` when set; otherwise it falls back to `0` (no timeout).
 
 Tool params:
 
@@ -79,7 +80,7 @@ Tool params:
 - `agentId?` (optional; spawn under another agent id if allowed)
 - `model?` (optional; overrides the sub-agent model; invalid values are skipped and the sub-agent runs on the default model with a warning in the tool result)
 - `thinking?` (optional; overrides thinking level for the sub-agent run)
-- `runTimeoutSeconds?` (default `0`; when set, the sub-agent run is aborted after N seconds)
+- `runTimeoutSeconds?` (defaults to `agents.defaults.subagents.runTimeoutSeconds` when set, otherwise `0`; when set, the sub-agent run is aborted after N seconds)
 - `thread?` (default `false`; when `true`, requests channel thread binding for this sub-agent session)
 - `mode?` (`run|session`)
   - default is `run`
@@ -148,6 +149,7 @@ By default, sub-agents cannot spawn their own sub-agents (`maxSpawnDepth: 1`). Y
         maxSpawnDepth: 2, // allow sub-agents to spawn children (default: 1)
         maxChildrenPerAgent: 5, // max active children per agent session (default: 5)
         maxConcurrent: 8, // global concurrency lane cap (default: 8)
+        runTimeoutSeconds: 900, // default timeout for sessions_spawn when omitted (0 = no timeout)
       },
     },
   },