diff --git a/app/src-tauri/src/lib.rs b/app/src-tauri/src/lib.rs
index d7287ab48..1a3842457 100644
--- a/app/src-tauri/src/lib.rs
+++ b/app/src-tauri/src/lib.rs
@@ -1821,21 +1821,27 @@ pub fn run() {
     // burns through the same 2 MB. In `crahs.log` (2026-05-17, build
     // 0.53.49) that tower plus the serde-monomorphised `Config` Visitor
     // frames pushed past the guard page and aborted with
-    // `SIGBUS / KERN_PROTECTION_FAILURE`. The structural fix
-    // (`spawn_blocking` for the TOML parse + cache in
-    // `src/openhuman/config/{schema/load.rs, ops.rs}`) moves the
-    // largest contributor off the worker; bumping the worker stack
-    // itself gives the rest of the tower comfortable headroom so future
-    // additions don't immediately re-tip the same scale. 8 MiB matches
-    // the OS-default pthread main-thread stack on macOS, so we can
-    // assume "as much room as the main thread" everywhere.
+    // `SIGBUS / KERN_PROTECTION_FAILURE`.
+    //
+    // The structural fix (`spawn_blocking` for the TOML parse + cache in
+    // `src/openhuman/config/{schema/load.rs, ops.rs}`) moves the largest
+    // contributor off the worker. An initial 8 MiB bump shipped here was
+    // enough for that single tower, but sub-agent delegation (issue #3159
+    // / PR #3155) re-tipped the scale: the standalone `openhuman-core`
+    // CLI server still aborted with `Abort trap: 6 / fatal runtime error:
+    // stack overflow` once an orchestrator delegated. PR #3155 raised the
+    // standalone server to 16 MiB; the desktop Tauri host is the *same*
+    // tower running on a *different* runtime and needs the same headroom.
+    // Share the constant with the rest of `src/core/*` via
+    // [`openhuman_core::core::runtime::AGENT_WORKER_STACK_BYTES`] so all
+    // multi-thread runtimes that may host an agent turn stay in sync.
     //
     // Must happen before any `tauri::async_runtime::*` call, otherwise
     // `set(...)` panics with "runtime already initialized".
     {
         let custom_runtime = tokio::runtime::Builder::new_multi_thread()
             .enable_all()
-            .thread_stack_size(8 * 1024 * 1024)
+            .thread_stack_size(openhuman_core::core::runtime::AGENT_WORKER_STACK_BYTES)
             .build()
             .expect("build custom tokio runtime for tauri async surface");
         let handle = custom_runtime.handle().clone();
diff --git a/src/core/agent_cli.rs b/src/core/agent_cli.rs
index 57c5282f7..4a51e47c7 100644
--- a/src/core/agent_cli.rs
+++ b/src/core/agent_cli.rs
@@ -122,6 +122,7 @@ fn run_dump_all(args: &[String]) -> Result<()> {
 
     let rt = tokio::runtime::Builder::new_multi_thread()
         .enable_all()
+        .thread_stack_size(crate::core::runtime::AGENT_WORKER_STACK_BYTES)
         .build()?;
     log::debug!("[agent-cli] run_dump_all: calling dump_all_agent_prompts");
     let dumps = rt.block_on(async {
@@ -253,6 +254,7 @@ fn run_dump_prompt(args: &[String]) -> Result<()> {
 
     let rt = tokio::runtime::Builder::new_multi_thread()
         .enable_all()
+        .thread_stack_size(crate::core::runtime::AGENT_WORKER_STACK_BYTES)
         .build()?;
     log::debug!("[agent-cli] run_dump_prompt: calling dump_agent_prompt");
     let dumped = rt.block_on(async { dump_agent_prompt(options).await })?;
diff --git a/src/core/cli.rs b/src/core/cli.rs
index 5c4d592d2..805edca37 100644
--- a/src/core/cli.rs
+++ b/src/core/cli.rs
@@ -288,7 +288,7 @@ fn run_server_command(args: &[String]) -> Result<()> {
     // the JSON-RPC server down mid-request. Give workers a roomier stack.
     let rt = tokio::runtime::Builder::new_multi_thread()
         .enable_all()
-        .thread_stack_size(16 * 1024 * 1024)
+        .thread_stack_size(crate::core::runtime::AGENT_WORKER_STACK_BYTES)
         .build()?;
     rt.block_on(async {
         crate::core::jsonrpc::run_server(host.as_deref(), port, socketio_enabled).await
@@ -337,8 +337,11 @@ fn run_call_command(args: &[String]) -> Result<()> {
     let method = method.ok_or_else(|| anyhow::anyhow!("--method is required"))?;
     let params = parse_json_params(&params).map_err(anyhow::Error::msg)?;
 
+    // `call` invokes a JSON-RPC method that may run an orchestrator turn
+    // (e.g. `agent.chat`), so it needs the same roomy stack as the server.
     let rt = tokio::runtime::Builder::new_multi_thread()
         .enable_all()
+        .thread_stack_size(crate::core::runtime::AGENT_WORKER_STACK_BYTES)
         .build()?;
     let value = rt
         .block_on(async { invoke_method(default_state(), &method, params).await })
@@ -415,8 +418,11 @@ fn run_namespace_command(
     let method = all::rpc_method_from_parts(namespace, function)
         .ok_or_else(|| anyhow::anyhow!("unregistered controller '{namespace}.{function}'"))?;
 
+    // Same as the explicit `call` path above — any registered controller may
+    // ultimately drive an orchestrator turn.
     let rt = tokio::runtime::Builder::new_multi_thread()
         .enable_all()
+        .thread_stack_size(crate::core::runtime::AGENT_WORKER_STACK_BYTES)
         .build()?;
     let value = rt
         .block_on(async { invoke_method(default_state(), &method, Value::Object(params)).await })
diff --git a/src/core/mod.rs b/src/core/mod.rs
index a7ae071c7..3a2f185a9 100644
--- a/src/core/mod.rs
+++ b/src/core/mod.rs
@@ -20,6 +20,7 @@ pub mod logging;
 pub mod memory_cli;
 pub mod observability;
 pub mod rpc_log;
+pub mod runtime;
 pub mod shutdown;
 pub mod socketio;
 pub mod types;
diff --git a/src/core/runtime.rs b/src/core/runtime.rs
new file mode 100644
index 000000000..1f83bb300
--- /dev/null
+++ b/src/core/runtime.rs
@@ -0,0 +1,16 @@
+//! Shared tokio runtime tuning constants.
+//!
+//! A single agent turn is a very large async state machine (system prompt +
+//! hundreds of tool specs + the nested provider/tool loop), and delegating
+//! to a sub-agent runs another full turn one level down. Even with the inner
+//! sub-agent future boxed, that nesting overflows tokio's default 2 MiB
+//! worker-thread stack and aborts the whole process (SIGABRT:
+//! "thread 'tokio-rt-worker' has overflowed its stack").
+//!
+//! PR #3155 set this on the standalone `openhuman-core run` JSON-RPC server.
+//! Issue #3159 calls out that every other multi-thread runtime that can host
+//! an agent turn (the desktop Tauri host's runtime, `agent_cli`, the rest of
+//! `cli.rs`, …) shares the same exposure. Centralising the value keeps them
+//! in sync; downstream call sites should set `.thread_stack_size(AGENT_WORKER_STACK_BYTES)`
+//! on every multi-thread runtime that may host an agent turn.
+pub const AGENT_WORKER_STACK_BYTES: usize = 16 * 1024 * 1024;