diff --git a/Cargo.lock b/Cargo.lock
index 7b23eb0..e3cb70e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -933,6 +933,7 @@ dependencies = [
  "sha2",
  "substrate-identity-store",
  "substrate-ipc",
+ "substrate-session",
  "tempfile",
  "thiserror 2.0.18",
  "tokio",
@@ -1537,6 +1538,17 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "substrate-session"
+version = "0.1.0"
+dependencies = [
+ "async-trait",
+ "chrono",
+ "guildhouse-did",
+ "serde",
+ "thiserror 2.0.18",
+]
+
 [[package]]
 name = "subtle"
 version = "2.6.1"
diff --git a/Cargo.toml b/Cargo.toml
index ae8a294..8c0d4cc 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,5 +25,6 @@ atty = "0.2"
 tracing = "0.1"
 substrate-ipc = { path = "../substrate/crates/substrate-ipc" }
 substrate-identity-store = { path = "../substrate/crates/substrate-identity-store" }
+substrate-session = { path = "../substrate-session" }
 tokio = { version = "1", features = ["full"] }
 libc = "0.2"
diff --git a/libgsh/Cargo.toml b/libgsh/Cargo.toml
index d848607..a727198 100644
--- a/libgsh/Cargo.toml
+++ b/libgsh/Cargo.toml
@@ -16,6 +16,7 @@ dirs = { workspace = true }
 tracing = { workspace = true }
 substrate-ipc = { workspace = true }
 substrate-identity-store = { workspace = true, optional = true }
+substrate-session = { workspace = true }
 tokio = { workspace = true }
 libc = { workspace = true }
 
diff --git a/libgsh/src/shell_tier.rs b/libgsh/src/shell_tier.rs
index 0a0fe6b..94bdbd0 100644
--- a/libgsh/src/shell_tier.rs
+++ b/libgsh/src/shell_tier.rs
@@ -1,263 +1 @@
-// Copyright 2026 Guildhouse Dev
-// SPDX-License-Identifier: Apache-2.0
-
-//! Typed shell hierarchy (T0–T6).
-//!
-//! Local definition matching org-ops-core's `ShellTier`. Kept here to
-//! avoid pulling the full org-ops-core dependency tree into gsh. If a
-//! shared governance-types crate is created, consolidate there.
-//!
-//! ```text
-//! T0 Genesis → T1 Infrastructure → ┬─ T2 Operator → ┬─ T3 Agent
-//!                                   │                └─ T4 Task
-//!                                   ├─ T5 Forensic
-//!                                   └─ T6 Recovery
-//! ```
-
-use std::fmt;
-use std::str::FromStr;
-
-use serde::{Deserialize, Serialize};
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
-pub enum ShellTier {
-    T0Genesis,
-    T1Infrastructure,
-    T2Operator,
-    T3Agent,
-    T4Task,
-    T5Forensic,
-    T6Recovery,
-}
-
-impl ShellTier {
-    pub fn numeric_level(&self) -> u8 {
-        match self {
-            Self::T0Genesis => 0,
-            Self::T1Infrastructure => 1,
-            Self::T2Operator => 2,
-            Self::T3Agent => 3,
-            Self::T4Task => 4,
-            Self::T5Forensic => 5,
-            Self::T6Recovery => 6,
-        }
-    }
-
-    pub fn from_numeric(n: u8) -> Option<Self> {
-        match n {
-            0 => Some(Self::T0Genesis),
-            1 => Some(Self::T1Infrastructure),
-            2 => Some(Self::T2Operator),
-            3 => Some(Self::T3Agent),
-            4 => Some(Self::T4Task),
-            5 => Some(Self::T5Forensic),
-            6 => Some(Self::T6Recovery),
-            _ => None,
-        }
-    }
-
-    pub fn label(&self) -> &'static str {
-        match self {
-            Self::T0Genesis => "Genesis",
-            Self::T1Infrastructure => "Infrastructure",
-            Self::T2Operator => "Operator",
-            Self::T3Agent => "Agent",
-            Self::T4Task => "Task",
-            Self::T5Forensic => "Forensic",
-            Self::T6Recovery => "Recovery",
-        }
-    }
-
-    pub fn parent(&self) -> Option<ShellTier> {
-        match self {
-            Self::T0Genesis => None,
-            Self::T1Infrastructure => Some(Self::T0Genesis),
-            Self::T2Operator => Some(Self::T1Infrastructure),
-            Self::T3Agent => Some(Self::T2Operator),
-            Self::T4Task => Some(Self::T2Operator),
-            Self::T5Forensic => Some(Self::T1Infrastructure),
-            Self::T6Recovery => Some(Self::T1Infrastructure),
-        }
-    }
-
-    pub fn satisfies(&self, required: ShellTier) -> bool {
-        if *self == required {
-            return true;
-        }
-        let mut current = required;
-        while let Some(p) = current.parent() {
-            if p == *self {
-                return true;
-            }
-            current = p;
-        }
-        false
-    }
-
-    /// Map a legacy `GSH_SHELL_CLASS` string to a tier.
-    pub fn from_shell_class(class: &str) -> Self {
-        match class {
-            "System" => Self::T1Infrastructure,
-            "Application" => Self::T2Operator,
-            _ => Self::T2Operator,
-        }
-    }
-
-    /// Return the legacy shell class string for backward compatibility.
-    pub fn to_shell_class(&self) -> &'static str {
-        match self {
-            Self::T0Genesis | Self::T1Infrastructure => "System",
-            _ => "Application",
-        }
-    }
-}
-
-impl Default for ShellTier {
-    fn default() -> Self {
-        ShellTier::T2Operator
-    }
-}
-
-impl fmt::Display for ShellTier {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "T{} ({})", self.numeric_level(), self.label())
-    }
-}
-
-impl FromStr for ShellTier {
-    type Err = String;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        if let Ok(n) = s.parse::<u8>() {
-            return Self::from_numeric(n).ok_or_else(|| format!("unknown shell tier: {s}"));
-        }
-        match s.to_lowercase().trim() {
-            "t0" | "genesis" | "t0genesis" => Ok(Self::T0Genesis),
-            "t1" | "infrastructure" | "t1infrastructure" => Ok(Self::T1Infrastructure),
-            "t2" | "operator" | "t2operator" => Ok(Self::T2Operator),
-            "t3" | "agent" | "t3agent" => Ok(Self::T3Agent),
-            "t4" | "task" | "t4task" => Ok(Self::T4Task),
-            "t5" | "forensic" | "t5forensic" => Ok(Self::T5Forensic),
-            "t6" | "recovery" | "t6recovery" => Ok(Self::T6Recovery),
-            other => Err(format!("unknown shell tier: {other}")),
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn default_is_t2() {
-        assert_eq!(ShellTier::default(), ShellTier::T2Operator);
-    }
-
-    #[test]
-    fn display_format() {
-        assert_eq!(format!("{}", ShellTier::T0Genesis), "T0 (Genesis)");
-        assert_eq!(format!("{}", ShellTier::T2Operator), "T2 (Operator)");
-        assert_eq!(format!("{}", ShellTier::T5Forensic), "T5 (Forensic)");
-    }
-
-    #[test]
-    fn parse_canonical_short() {
-        assert_eq!("t0".parse::<ShellTier>().unwrap(), ShellTier::T0Genesis);
-        assert_eq!("T2".parse::<ShellTier>().unwrap(), ShellTier::T2Operator);
-        assert_eq!("T6".parse::<ShellTier>().unwrap(), ShellTier::T6Recovery);
-    }
-
-    #[test]
-    fn parse_numeric_string() {
-        assert_eq!("0".parse::<ShellTier>().unwrap(), ShellTier::T0Genesis);
-        assert_eq!("3".parse::<ShellTier>().unwrap(), ShellTier::T3Agent);
-        assert_eq!("6".parse::<ShellTier>().unwrap(), ShellTier::T6Recovery);
-        assert!("7".parse::<ShellTier>().is_err());
-    }
-
-    #[test]
-    fn parse_label() {
-        assert_eq!("genesis".parse::<ShellTier>().unwrap(), ShellTier::T0Genesis);
-        assert_eq!("operator".parse::<ShellTier>().unwrap(), ShellTier::T2Operator);
-        assert_eq!("forensic".parse::<ShellTier>().unwrap(), ShellTier::T5Forensic);
-    }
-
-    #[test]
-    fn parse_invalid() {
-        assert!("t7".parse::<ShellTier>().is_err());
-        assert!("bogus".parse::<ShellTier>().is_err());
-    }
-
-    #[test]
-    fn parent_tree() {
-        assert_eq!(ShellTier::T0Genesis.parent(), None);
-        assert_eq!(ShellTier::T1Infrastructure.parent(), Some(ShellTier::T0Genesis));
-        assert_eq!(ShellTier::T2Operator.parent(), Some(ShellTier::T1Infrastructure));
-        assert_eq!(ShellTier::T3Agent.parent(), Some(ShellTier::T2Operator));
-        assert_eq!(ShellTier::T4Task.parent(), Some(ShellTier::T2Operator));
-        assert_eq!(ShellTier::T5Forensic.parent(), Some(ShellTier::T1Infrastructure));
-        assert_eq!(ShellTier::T6Recovery.parent(), Some(ShellTier::T1Infrastructure));
-    }
-
-    #[test]
-    fn satisfies_self() {
-        for tier in [
-            ShellTier::T0Genesis, ShellTier::T1Infrastructure, ShellTier::T2Operator,
-            ShellTier::T3Agent, ShellTier::T4Task, ShellTier::T5Forensic, ShellTier::T6Recovery,
-        ] {
-            assert!(tier.satisfies(tier));
-        }
-    }
-
-    #[test]
-    fn t0_satisfies_everything() {
-        assert!(ShellTier::T0Genesis.satisfies(ShellTier::T4Task));
-        assert!(ShellTier::T0Genesis.satisfies(ShellTier::T6Recovery));
-    }
-
-    #[test]
-    fn t2_satisfies_t3_t4_not_t5_t6() {
-        assert!(ShellTier::T2Operator.satisfies(ShellTier::T3Agent));
-        assert!(ShellTier::T2Operator.satisfies(ShellTier::T4Task));
-        assert!(!ShellTier::T2Operator.satisfies(ShellTier::T5Forensic));
-        assert!(!ShellTier::T2Operator.satisfies(ShellTier::T6Recovery));
-    }
-
-    #[test]
-    fn leaf_does_not_satisfy_sibling() {
-        assert!(!ShellTier::T3Agent.satisfies(ShellTier::T4Task));
-        assert!(!ShellTier::T5Forensic.satisfies(ShellTier::T6Recovery));
-    }
-
-    #[test]
-    fn from_shell_class_mapping() {
-        assert_eq!(ShellTier::from_shell_class("Application"), ShellTier::T2Operator);
-        assert_eq!(ShellTier::from_shell_class("System"), ShellTier::T1Infrastructure);
-        assert_eq!(ShellTier::from_shell_class("Unknown"), ShellTier::T2Operator);
-    }
-
-    #[test]
-    fn to_shell_class_backward_compat() {
-        assert_eq!(ShellTier::T0Genesis.to_shell_class(), "System");
-        assert_eq!(ShellTier::T1Infrastructure.to_shell_class(), "System");
-        assert_eq!(ShellTier::T2Operator.to_shell_class(), "Application");
-        assert_eq!(ShellTier::T3Agent.to_shell_class(), "Application");
-        assert_eq!(ShellTier::T5Forensic.to_shell_class(), "Application");
-    }
-
-    #[test]
-    fn numeric_levels() {
-        assert_eq!(ShellTier::T0Genesis.numeric_level(), 0);
-        assert_eq!(ShellTier::T3Agent.numeric_level(), 3);
-        assert_eq!(ShellTier::T6Recovery.numeric_level(), 6);
-    }
-
-    #[test]
-    fn from_numeric_round_trip() {
-        for n in 0..=6u8 {
-            let tier = ShellTier::from_numeric(n).unwrap();
-            assert_eq!(tier.numeric_level(), n);
-        }
-        assert!(ShellTier::from_numeric(7).is_none());
-    }
-}
+pub use substrate_session::ShellTier;