diff --git a/crates/tracedecay-agent-hosts/build.rs b/crates/tracedecay-agent-hosts/build.rs
index 0c81e4576f..864bb705c5 100644
--- a/crates/tracedecay-agent-hosts/build.rs
+++ b/crates/tracedecay-agent-hosts/build.rs
@@ -185,12 +185,18 @@ fn main() {
         &mut code,
         "GENERATED_CODEX_AGENT_FILES",
         agents.iter().map(|agent| {
+            // Keep read-only specialists on Terra so they do not silently
+            // inherit an expensive primary Sol session. Sol Advisor owns the
+            // separately configured explicit final/high-risk review lane.
+            let (model, model_reasoning_effort) = ("gpt-5.6-terra", "high");
             (
                 format!("tracedecay-{}.toml", agent.name),
                 format!(
-                    "name = {}\ndescription = {}\nsandbox_mode = \"read-only\"\ndeveloper_instructions = {}\n",
+                    "name = {}\ndescription = {}\nmodel = {}\nmodel_reasoning_effort = {}\nsandbox_mode = \"read-only\"\ndeveloper_instructions = {}\n",
                     quoted_string(&format!("tracedecay-{}", agent.name)),
                     quoted_string(&agent.description),
+                    quoted_string(model),
+                    quoted_string(model_reasoning_effort),
                     quoted_string(&agent.body),
                 ),
             )
diff --git a/tests/agent_suite/claude_plugin_bundle_test.rs b/tests/agent_suite/claude_plugin_bundle_test.rs
index 5534a9df62..3fadb07e6c 100644
--- a/tests/agent_suite/claude_plugin_bundle_test.rs
+++ b/tests/agent_suite/claude_plugin_bundle_test.rs
@@ -588,6 +588,8 @@ fn cursor_and_codex_agents_are_generated_from_the_canonical_catalog() {
             Some(required_scalar(&claude, "description", &claude_path).as_str())
         );
         assert_eq!(codex_toml["sandbox_mode"].as_str(), Some("read-only"));
+        assert_eq!(codex_toml["model"].as_str(), Some("gpt-5.6-terra"));
+        assert_eq!(codex_toml["model_reasoning_effort"].as_str(), Some("high"));
         assert_eq!(
             codex_toml["developer_instructions"].as_str().map(str::trim),
             Some(canonical_body.trim())