diff --git a/src/plugin-handlers/agent-config-handler.test.ts b/src/plugin-handlers/agent-config-handler.test.ts
index ac7551782..db7146f77 100644
--- a/src/plugin-handlers/agent-config-handler.test.ts
+++ b/src/plugin-handlers/agent-config-handler.test.ts
@@ -9,7 +9,7 @@ import type { OhMyOpenCodeConfig } from "../config"
 import * as agentLoader from "../features/claude-code-agent-loader"
 import * as skillLoader from "../features/opencode-skill-loader"
 import type { LoadedSkill } from "../features/opencode-skill-loader"
-import { getAgentDisplayName } from "../shared/agent-display-names"
+import { getAgentDisplayName, getAgentRuntimeName } from "../shared/agent-display-names"
 import { applyAgentConfig } from "./agent-config-handler"
 import type { PluginComponents } from "./plugin-components-loader"
 
@@ -203,7 +203,7 @@ describe("applyAgentConfig builtin override protection", () => {
     // then
     expect(result[BUILTIN_SISYPHUS_DISPLAY_NAME]).toEqual({
       ...builtinSisyphusConfig,
-      name: getAgentDisplayName("sisyphus"),
+      name: getAgentRuntimeName("sisyphus"),
     })
   })
 
@@ -228,7 +228,7 @@ describe("applyAgentConfig builtin override protection", () => {
     // then
     expect(result[BUILTIN_SISYPHUS_DISPLAY_NAME]).toEqual({
       ...builtinSisyphusConfig,
-      name: getAgentDisplayName("sisyphus"),
+      name: getAgentRuntimeName("sisyphus"),
     })
     expect(result.SiSyPhUs).toBeUndefined()
   })
@@ -255,7 +255,7 @@ describe("applyAgentConfig builtin override protection", () => {
     // then
     expect(result[BUILTIN_SISYPHUS_DISPLAY_NAME]).toEqual({
       ...builtinSisyphusConfig,
-      name: getAgentDisplayName("sisyphus"),
+      name: getAgentRuntimeName("sisyphus"),
     })
   })
 
diff --git a/src/plugin-handlers/agent-config-handler.ts b/src/plugin-handlers/agent-config-handler.ts
index 8c4a8b1fd..732576ec9 100644
--- a/src/plugin-handlers/agent-config-handler.ts
+++ b/src/plugin-handlers/agent-config-handler.ts
@@ -2,7 +2,7 @@ import { createBuiltinAgents } from "../agents";
 import { createSisyphusJuniorAgentWithOverrides } from "../agents/sisyphus-junior";
 import type { OhMyOpenCodeConfig } from "../config";
 import { isTaskSystemEnabled, log, migrateAgentConfig } from "../shared";
-import { getAgentDisplayName } from "../shared/agent-display-names";
+import { getAgentDisplayName, getAgentRuntimeName } from "../shared/agent-display-names";
 import { AGENT_NAME_MAP } from "../shared/migration";
 import { registerAgentName } from "../features/claude-code-session-state";
 import {
@@ -159,10 +159,10 @@ export async function applyAgentConfig(params: {
   if (isSisyphusEnabled && builtinAgents.sisyphus) {
     if (configuredDefaultAgent) {
       (params.config as { default_agent?: string }).default_agent =
-        getAgentDisplayName(configuredDefaultAgent);
+        getAgentRuntimeName(configuredDefaultAgent);
     } else {
       (params.config as { default_agent?: string }).default_agent =
-        getAgentDisplayName("sisyphus");
+        getAgentRuntimeName("sisyphus");
     }
 
     // Assembly order: Sisyphus -> Hephaestus -> Prometheus -> Atlas
diff --git a/src/plugin-handlers/agent-key-remapper.test.ts b/src/plugin-handlers/agent-key-remapper.test.ts
index 94a81a0b6..e792d8755 100644
--- a/src/plugin-handlers/agent-key-remapper.test.ts
+++ b/src/plugin-handlers/agent-key-remapper.test.ts
@@ -1,6 +1,6 @@
 import { describe, it, expect } from "bun:test"
 import { remapAgentKeysToDisplayNames } from "./agent-key-remapper"
-import { getAgentDisplayName } from "../shared/agent-display-names"
+import { getAgentDisplayName, getAgentRuntimeName } from "../shared/agent-display-names"
 
 describe("remapAgentKeysToDisplayNames", () => {
   it("remaps known agent keys to display names", () => {
@@ -106,7 +106,7 @@ describe("remapAgentKeysToDisplayNames", () => {
     }
   })
 
-  it("preserves clean keys and rewrites core agent name fields to canonical display names", () => {
+  it("preserves clean keys but rewrites core agent name fields to runtime names for sort ordering", () => {
     // given agents with raw config-key names
     const agents = {
       sisyphus: { name: "sisyphus", prompt: "test", mode: "primary" },
@@ -119,7 +119,7 @@ describe("remapAgentKeysToDisplayNames", () => {
     // when remapping
     const result = remapAgentKeysToDisplayNames(agents)
 
-    // then keys stay HTTP-header-safe, and nested names match the lookup-safe display names
+    // then keys stay HTTP-header-safe, name fields carry ZWSP for OpenCode localeCompare sort
     expect(Object.keys(result).slice(0, 4)).toEqual([
       getAgentDisplayName("sisyphus"),
       getAgentDisplayName("hephaestus"),
@@ -127,29 +127,29 @@ describe("remapAgentKeysToDisplayNames", () => {
       getAgentDisplayName("atlas"),
     ])
     expect(result[getAgentDisplayName("sisyphus")]).toEqual({
-      name: getAgentDisplayName("sisyphus"),
+      name: getAgentRuntimeName("sisyphus"),
       prompt: "test",
       mode: "primary",
     })
     expect(result[getAgentDisplayName("hephaestus")]).toEqual({
-      name: getAgentDisplayName("hephaestus"),
+      name: getAgentRuntimeName("hephaestus"),
       prompt: "test",
       mode: "primary",
     })
     expect(result[getAgentDisplayName("prometheus")]).toEqual({
-      name: getAgentDisplayName("prometheus"),
+      name: getAgentRuntimeName("prometheus"),
       prompt: "test",
       mode: "all",
     })
     expect(result[getAgentDisplayName("atlas")]).toEqual({
-      name: getAgentDisplayName("atlas"),
+      name: getAgentRuntimeName("atlas"),
       prompt: "test",
       mode: "primary",
     })
     expect(result.oracle).toEqual({ name: "oracle", prompt: "test", mode: "subagent" })
   })
 
-  it("backfills canonical display names for core agents when builtin configs omit name", () => {
+  it("backfills runtime names for core agents when builtin configs omit name", () => {
     // given builtin-style configs without name fields
     const agents = {
       sisyphus: { prompt: "test", mode: "primary" },
@@ -161,24 +161,24 @@ describe("remapAgentKeysToDisplayNames", () => {
     // when remapping
     const result = remapAgentKeysToDisplayNames(agents)
 
-    // then OpenCode receives lookup-safe display names and uses order for sorting
+    // then OpenCode's name sort can still preserve canonical order
     expect(result[getAgentDisplayName("sisyphus")]).toEqual({
-      name: getAgentDisplayName("sisyphus"),
+      name: getAgentRuntimeName("sisyphus"),
       prompt: "test",
       mode: "primary",
     })
     expect(result[getAgentDisplayName("hephaestus")]).toEqual({
-      name: getAgentDisplayName("hephaestus"),
+      name: getAgentRuntimeName("hephaestus"),
       prompt: "test",
       mode: "primary",
     })
     expect(result[getAgentDisplayName("prometheus")]).toEqual({
-      name: getAgentDisplayName("prometheus"),
+      name: getAgentRuntimeName("prometheus"),
       prompt: "test",
       mode: "all",
     })
     expect(result[getAgentDisplayName("atlas")]).toEqual({
-      name: getAgentDisplayName("atlas"),
+      name: getAgentRuntimeName("atlas"),
       prompt: "test",
       mode: "primary",
     })
diff --git a/src/plugin-handlers/agent-key-remapper.ts b/src/plugin-handlers/agent-key-remapper.ts
index c15241301..93499b014 100644
--- a/src/plugin-handlers/agent-key-remapper.ts
+++ b/src/plugin-handlers/agent-key-remapper.ts
@@ -1,4 +1,4 @@
-import { getAgentDisplayName } from "../shared/agent-display-names"
+import { getAgentDisplayName, getAgentRuntimeName } from "../shared/agent-display-names"
 
 function rewriteAgentNameForListDisplay(
   key: string,
@@ -11,7 +11,7 @@ function rewriteAgentNameForListDisplay(
   const agent = value as Record<string, unknown>
   return {
     ...agent,
-    name: getAgentDisplayName(key),
+    name: getAgentRuntimeName(key),
   }
 }
 
diff --git a/src/plugin-handlers/config-handler.test.ts b/src/plugin-handlers/config-handler.test.ts
index 8fdc2d29c..4cde1dadb 100644
--- a/src/plugin-handlers/config-handler.test.ts
+++ b/src/plugin-handlers/config-handler.test.ts
@@ -355,19 +355,19 @@ describe("Plan agent demote behavior", () => {
     expect(emittedCoreEntries).toEqual([
       [
         getAgentDisplayName("sisyphus"),
-        expect.objectContaining({ name: getAgentDisplayName("sisyphus") }),
+        expect.objectContaining({ name: getAgentRuntimeName("sisyphus") }),
       ],
       [
         getAgentDisplayName("hephaestus"),
-        expect.objectContaining({ name: getAgentDisplayName("hephaestus") }),
+        expect.objectContaining({ name: getAgentRuntimeName("hephaestus") }),
       ],
       [
         getAgentDisplayName("prometheus"),
-        expect.objectContaining({ name: getAgentDisplayName("prometheus") }),
+        expect.objectContaining({ name: getAgentRuntimeName("prometheus") }),
       ],
       [
         getAgentDisplayName("atlas"),
-        expect.objectContaining({ name: getAgentDisplayName("atlas") }),
+        expect.objectContaining({ name: getAgentRuntimeName("atlas") }),
       ],
     ])
   })
@@ -536,7 +536,7 @@ describe("default_agent behavior with Sisyphus orchestration", () => {
     await handler(config)
 
     // then
-    expect(config.default_agent).toBe(getAgentDisplayName("hephaestus"))
+    expect(config.default_agent).toBe(getAgentRuntimeName("hephaestus"))
   })
 
   test("canonicalizes configured default_agent when key uses mixed case", async () => {
@@ -560,7 +560,7 @@ describe("default_agent behavior with Sisyphus orchestration", () => {
     await handler(config)
 
     // then
-    expect(config.default_agent).toBe(getAgentDisplayName("hephaestus"))
+    expect(config.default_agent).toBe(getAgentRuntimeName("hephaestus"))
   })
 
   test("canonicalizes configured default_agent key to display name", async () => {
@@ -584,7 +584,7 @@ describe("default_agent behavior with Sisyphus orchestration", () => {
     await handler(config)
 
     // #then
-    expect(config.default_agent).toBe(getAgentDisplayName("hephaestus"))
+    expect(config.default_agent).toBe(getAgentRuntimeName("hephaestus"))
   })
 
   test("preserves existing display-name default_agent", async () => {
@@ -632,7 +632,7 @@ describe("default_agent behavior with Sisyphus orchestration", () => {
     await handler(config)
 
     // #then
-    expect(config.default_agent).toBe(getAgentDisplayName("sisyphus"))
+    expect(config.default_agent).toBe(getAgentRuntimeName("sisyphus"))
   })
 
   test("uses canonical default_agent display name so OpenCode lookups match emitted agent keys", async () => {
@@ -656,7 +656,7 @@ describe("default_agent behavior with Sisyphus orchestration", () => {
     await handler(config)
 
     // then
-    expect(config.default_agent).toBe(getAgentDisplayName("hephaestus"))
+    expect(config.default_agent).toBe(getAgentRuntimeName("hephaestus"))
   })
 
   test("sets default_agent to sisyphus when configured default_agent is empty after trim", async () => {
@@ -680,7 +680,7 @@ describe("default_agent behavior with Sisyphus orchestration", () => {
     await handler(config)
 
     // then
-    expect(config.default_agent).toBe(getAgentDisplayName("sisyphus"))
+    expect(config.default_agent).toBe(getAgentRuntimeName("sisyphus"))
   })
 
   test("preserves custom default_agent names while trimming whitespace", async () => {