diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f580a5f..ae5291fa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -110,6 +110,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Sub-agent description copy** — `agent_spawn` tool description
   and `prompts/base.md` updated to reflect the new default cap of
   10 (was stale "Max 5 in flight").
+- **`agent_spawn` / `agent_assign` schema descriptions** (#404
+  follow-up) — type/agent_name property descriptions now list
+  `implementer` and `verifier` so the model surfaces those roles
+  without having to discover them from `docs/SUBAGENTS.md`. Adds
+  the long-form aliases (`builder` / `validator` / `tester`) on
+  `agent_assign` for parity with the alias map.
 - **RLM tool family** (#512) — `rlm` tool cards map to
   `ToolFamily::Rlm` and render `rlm`, not `swarm`. Stale "swarm"
   wording cleaned out of docs / comments / tests.
diff --git a/crates/tui/src/tools/subagent/mod.rs b/crates/tui/src/tools/subagent/mod.rs
index f480ae82..c6d3121b 100644
--- a/crates/tui/src/tools/subagent/mod.rs
+++ b/crates/tui/src/tools/subagent/mod.rs
@@ -1467,7 +1467,7 @@ impl ToolSpec for AgentSpawnTool {
                 },
                 "type": {
                     "type": "string",
-                    "description": "Sub-agent type: general, explore, plan, review, custom"
+                    "description": "Sub-agent type: general, explore, plan, review, implementer, verifier, custom. See docs/SUBAGENTS.md for posture per role."
                 },
                 "agent_type": {
                     "type": "string",
@@ -2325,7 +2325,7 @@ impl ToolSpec for DelegateToAgentTool {
             "properties": {
                 "agent_name": {
                     "type": "string",
-                    "description": "Name/type alias for the agent (general, explore, plan, review, worker, explorer, awaiter)"
+                    "description": "Name/type alias for the agent (general, explore, plan, review, implementer, verifier, worker, explorer, awaiter, builder, validator, tester)"
                 },
                 "type": {
                     "type": "string",