feat(config): add configurable agent ordering

assets/oh-my-opencode.schema.json

@@ -14,6 +14,14 @@
     "default_run_agent": {
       "type": "string"
     },
+    "agent_order": {
+      "maxItems": 64,
+      "type": "array",
+      "items": {
+        "type": "string",
+        "maxLength": 128
+      }
+    },
     "agent_definitions": {
       "type": "array",
       "items": {

docs/reference/configuration.md

@@ -161,7 +161,13 @@ Override built-in agent settings. Available agents: `sisyphus`, `hephaestus`, `p
 
 Disable agents entirely: `{ "disabled_agents": ["oracle", "multimodal-looker"] }`
 
-Core agents receive an injected runtime `order` field for deterministic Tab cycling in the UI: Sisyphus = 1, Hephaestus = 2, Prometheus = 3, Atlas = 4. This is not a user-configurable config key.
+Agent tab cycling defaults to Sisyphus, Hephaestus, Prometheus, Atlas. Override known agent ordering with `agent_order`; omitted core agents keep their default relative order. Unknown or duplicate names are ignored and reported with a config toast.
+
+```json
+{
+  "agent_order": ["hephaestus", "sisyphus", "prometheus", "atlas"]
+}
+```
 
 #### Agent Options
 

docs/reference/features.md

@@ -90,7 +90,7 @@ When running inside tmux:
 - Watch multiple agents work in real-time
 - Each pane shows agent output live
 - Auto-cleanup when agents complete
-- **Stable agent ordering**: core-agent tab cycling is deterministic via injected runtime order field (Sisyphus: 1, Hephaestus: 2, Prometheus: 3, Atlas: 4)
+- **Stable agent ordering**: core-agent tab cycling defaults to Sisyphus, Hephaestus, Prometheus, Atlas, and can be customized with `agent_order`
 
 Customize agent models, prompts, and permissions in `oh-my-opencode.jsonc`.
 

src/config/schema/oh-my-opencode-config.test.ts

@@ -38,3 +38,58 @@ describe("OhMyOpenCodeConfigSchema team_mode", () => {
     }
   })
 })
+
+describe("OhMyOpenCodeConfigSchema agent_order", () => {
+  it("accepts string agent ordering when provided", () => {
+    // given
+    const rawConfig = {
+      agent_order: ["hephaestus", "sisyphus", "prometheus", "atlas"],
+    }
+
+    // when
+    const result = OhMyOpenCodeConfigSchema.safeParse(rawConfig)
+
+    // then
+    expect(result.success).toBe(true)
+    if (result.success) {
+      expect(result.data.agent_order).toEqual([
+        "hephaestus",
+        "sisyphus",
+        "prometheus",
+        "atlas",
+      ])
+    }
+  })
+
+  it("allows agent_order omission", () => {
+    // given
+    const rawConfig = {}
+
+    // when
+    const result = OhMyOpenCodeConfigSchema.safeParse(rawConfig)
+
+    // then
+    expect(result.success).toBe(true)
+    if (result.success) {
+      expect(result.data.agent_order).toBeUndefined()
+    }
+  })
+
+  it("rejects abusive agent_order string length and item count", () => {
+    // given
+    const tooLongName = "x".repeat(129)
+    const tooManyNames = Array.from({ length: 65 }, (_, index) => `agent-${index}`)
+
+    // when
+    const tooLongResult = OhMyOpenCodeConfigSchema.safeParse({
+      agent_order: [tooLongName],
+    })
+    const tooManyResult = OhMyOpenCodeConfigSchema.safeParse({
+      agent_order: tooManyNames,
+    })
+
+    // then
+    expect(tooLongResult.success).toBe(false)
+    expect(tooManyResult.success).toBe(false)
+  })
+})

src/config/schema/oh-my-opencode-config.ts

@@ -32,6 +32,8 @@ export const OhMyOpenCodeConfigSchema = z.object({
   new_task_system_enabled: z.boolean().optional(),
   /** Default agent name for `oh-my-opencode run` (env: OPENCODE_DEFAULT_AGENT) */
   default_run_agent: z.string().optional(),
+  /** Preferred display order for known agents. Invalid names are ignored with a toast warning. */
+  agent_order: z.array(z.string().max(128)).max(64).optional(),
   /** Paths to external agent definition files (.md or .json) */
   agent_definitions: AgentDefinitionsConfigSchema,
   disabled_mcps: z.array(AnyMcpNameSchema).optional(),

src/index.test.ts

@@ -37,6 +37,8 @@ const mockCreateHooks = mock(() => ({
 const mockCreatePluginInterface = mock(() => ({}))
 const mockInitializeOpenClaw = mock(async () => {})
 const mockStartTmuxCheck = mock(() => {})
+const mockInstallAgentSortShim = mock(() => {})
+const mockSetAgentSortOrder = mock(() => {})
 
 let pluginModule: (typeof import("./index"))["default"]
 
@@ -95,6 +97,11 @@ function installIndexModuleMocks(): void {
     })),
   }))
 
+  mock.module("./shared/agent-sort-shim", () => ({
+    installAgentSortShim: mockInstallAgentSortShim,
+    setAgentSortOrder: mockSetAgentSortOrder,
+  }))
+
   mock.module("./openclaw", () => ({
     initializeOpenClaw: mockInitializeOpenClaw,
   }))
@@ -130,6 +137,8 @@ describe("oh-my-openagent plugin module", () => {
     mockCreatePluginInterface.mockClear()
     mockInitializeOpenClaw.mockClear()
     mockStartTmuxCheck.mockClear()
+    mockInstallAgentSortShim.mockClear()
+    mockSetAgentSortOrder.mockClear()
   })
 
   afterEach(() => {

src/index.ts

@@ -14,7 +14,7 @@ import { loadPluginConfig } from "./plugin-config"
 import { createModelCacheState } from "./plugin-state"
 import { createFirstMessageVariantGate } from "./shared/first-message-variant"
 import { injectServerAuthIntoClient, log, logLegacyPluginStartupWarning } from "./shared"
-import { installAgentSortShim } from "./shared/agent-sort-shim"
+import { installAgentSortShim, setAgentSortOrder } from "./shared/agent-sort-shim"
 import { detectExternalSkillPlugin, getSkillPluginConflictWarning } from "./shared/external-plugin-detector"
 import { startBackgroundCheck as startTmuxCheck } from "./tools/interactive-bash"
 
@@ -34,6 +34,7 @@ const serverPlugin: Plugin = async (input, _options): Promise<Hooks> => {
   injectServerAuthIntoClient(input.client)
 
   const pluginConfig = loadPluginConfig(input.directory, input)
+  setAgentSortOrder(pluginConfig.agent_order)
 
   if (pluginConfig.openclaw) {
     await initializeOpenClaw(pluginConfig.openclaw)

src/plugin-config.test.ts

@@ -1,9 +1,10 @@
-import { afterEach, describe, expect, it, mock, spyOn } from "bun:test";
+import { afterEach, describe, expect, it, mock } from "bun:test";
 import { chmodSync, existsSync, mkdtempSync, mkdirSync, readFileSync, realpathSync, rmSync, writeFileSync } from "node:fs"
 import { tmpdir } from "node:os"
 import { join } from "node:path"
-import { mergeConfigs, parseConfigPartially } from "./plugin-config";
+import { loadConfigFromPath, mergeConfigs, parseConfigPartially } from "./plugin-config";
 import { OhMyOpenCodeConfigSchema, type OhMyOpenCodeConfig, type TeamModeConfig } from "./config";
+import { clearConfigLoadErrors, getConfigLoadErrors } from "./shared/config-errors";
 
 const tempDirs: string[] = []
 type ConfigInput = Omit<Partial<OhMyOpenCodeConfig>, "team_mode"> & {
@@ -20,6 +21,7 @@ async function importFreshPluginConfigModule(): Promise<typeof import("./plugin-
 
 afterEach(() => {
   mock.restore()
+  clearConfigLoadErrors()
   delete process.env.OPENCODE_CONFIG_DIR
 
   for (const dir of tempDirs.splice(0)) {
@@ -273,6 +275,35 @@ describe("parseConfigPartially", () => {
       expect(result!.agents).toBeUndefined();
     });
 
+    it("should preserve valid agent_order when another section is invalid", () => {
+      const rawConfig = {
+        agent_order: ["hephaestus", "sisyphus", "prometheus", "atlas"],
+        disabled_skills: [42],
+      };
+
+      const result = parseConfigPartially(rawConfig);
+
+      expect(result?.agent_order).toEqual([
+        "hephaestus",
+        "sisyphus",
+        "prometheus",
+        "atlas",
+      ]);
+      expect(result?.disabled_skills).toBeUndefined();
+    });
+
+    it("should skip abusive agent_order when another section is valid", () => {
+      const rawConfig = {
+        agent_order: ["x".repeat(129)],
+        disabled_hooks: ["comment-checker"],
+      };
+
+      const result = parseConfigPartially(rawConfig);
+
+      expect(result?.agent_order).toBeUndefined();
+      expect(result?.disabled_hooks).toEqual(["comment-checker"]);
+    });
+
     it("should preserve valid agents when a non-agent section is invalid", () => {
       const rawConfig = {
         agents: {
@@ -349,6 +380,51 @@ describe("parseConfigPartially", () => {
   });
 });
 
+describe("loadConfigFromPath agent_order warnings", () => {
+  it("loads config and records warning for invalid agent_order entries", () => {
+    // given
+    const rootDir = mkdtempSync(join(tmpdir(), "agent-order-warning-"))
+    tempDirs.push(rootDir)
+    const configPath = join(rootDir, "oh-my-openagent.json")
+    writeJsonFile(configPath, {
+      agent_order: ["hephaestus", "not-real", "sisyphus", "hephaestus"],
+    })
+
+    // when
+    const result = loadConfigFromPath(configPath, {})
+
+    // then
+    expect(result?.agent_order).toEqual(["hephaestus", "not-real", "sisyphus", "hephaestus"])
+    expect(getConfigLoadErrors()).toEqual([
+      {
+        path: configPath,
+        error: 'agent_order warning - unknown agent names ignored: "not-real"; duplicate agent names ignored: "hephaestus"',
+      },
+    ])
+  })
+
+  it("sanitizes and caps invalid agent_order values before recording warnings", () => {
+    // given
+    const rootDir = mkdtempSync(join(tmpdir(), "agent-order-sanitize-"))
+    tempDirs.push(rootDir)
+    const configPath = join(rootDir, "oh-my-openagent.json")
+    writeJsonFile(configPath, {
+      agent_order: [
+        "\u001B[31mbad\u001B[0m",
+        ...Array.from({ length: 11 }, (_, index) => `missing-${index}`),
+      ],
+    })
+
+    // when
+    loadConfigFromPath(configPath, {})
+
+    // then
+    expect(getConfigLoadErrors()[0]?.error).toBe(
+      'agent_order warning - unknown agent names ignored: "[31mbad[0m", "missing-0", "missing-1", "missing-2", "missing-3", "missing-4", "missing-5", "missing-6", "missing-7", "missing-8", (+2 more)',
+    )
+  })
+})
+
 describe("loadPluginConfig", () => {
   it("should only honor mcp_env_allowlist from user config", async () => {
     // given

src/plugin-config.ts

@@ -16,6 +16,50 @@ import {
 } from "./shared";
 import { migrateLegacyConfigFile } from "./shared/migrate-legacy-config-file";
 import { CONFIG_BASENAME, LEGACY_CONFIG_BASENAME } from "./shared/plugin-identity";
+import { validateAgentOrder } from "./shared/agent-ordering";
+
+const CONTROL_CHARACTERS_REGEX = /[\u0000-\u001F\u007F-\u009F\u202A-\u202E\u2066-\u2069]/g;
+const MAX_AGENT_ORDER_WARNING_VALUES = 10;
+const MAX_AGENT_ORDER_WARNING_VALUE_LENGTH = 80;
+
+function formatAgentOrderWarningValues(values: readonly string[]): string {
+  const displayedValues = values.slice(0, MAX_AGENT_ORDER_WARNING_VALUES).map((value) => {
+    const sanitized = value.replace(CONTROL_CHARACTERS_REGEX, "");
+    const truncated = sanitized.length > MAX_AGENT_ORDER_WARNING_VALUE_LENGTH
+      ? `${sanitized.slice(0, MAX_AGENT_ORDER_WARNING_VALUE_LENGTH)}...`
+      : sanitized;
+    return JSON.stringify(truncated);
+  });
+
+  const remaining = values.length - displayedValues.length;
+  if (remaining > 0) {
+    displayedValues.push(`(+${remaining} more)`);
+  }
+
+  return displayedValues.join(", ");
+}
+
+function addAgentOrderWarnings(configPath: string, agentOrder: string[] | undefined): void {
+  if (!agentOrder) return;
+
+  const validation = validateAgentOrder(agentOrder);
+  const messages: string[] = [];
+
+  if (validation.invalid.length > 0) {
+    messages.push(`unknown agent names ignored: ${formatAgentOrderWarningValues(validation.invalid)}`);
+  }
+
+  if (validation.duplicates.length > 0) {
+    messages.push(`duplicate agent names ignored: ${formatAgentOrderWarningValues(validation.duplicates)}`);
+  }
+
+  if (messages.length === 0) return;
+
+  addConfigLoadError({
+    path: configPath,
+    error: `agent_order warning - ${messages.join("; ")}`,
+  });
+}
 
 function resolveHomeDirectory(): string {
   // Read env vars directly to bypass os.homedir() caching. Bun caches the
@@ -134,6 +178,7 @@ export function loadConfigFromPath(
       const result = OhMyOpenCodeConfigSchema.safeParse(rawConfig);
 
       if (result.success) {
+        addAgentOrderWarnings(configPath, result.data.agent_order);
         log(`Config loaded from ${configPath}`, { agents: result.data.agents });
         return result.data;
       }
@@ -149,6 +194,7 @@ export function loadConfigFromPath(
 
       const partialResult = parseConfigPartially(rawConfig);
       if (partialResult) {
+        addAgentOrderWarnings(configPath, partialResult.agent_order);
         log(`Partial config loaded from ${configPath}`, { agents: partialResult.agents });
         return partialResult;
       }

src/plugin-handlers/AGENTS.md

@@ -4,11 +4,12 @@
 
 ## CRITICAL: AGENT ORDERING
 
-The canonical agent order is **sisyphus → hephaestus → prometheus → atlas**.
+The default agent order is **sisyphus → hephaestus → prometheus → atlas**. User config may override it with `agent_order`; omitted core agents fall back to this default order.
 
 This order is enforced via two cooperating mechanisms:
-1. `CANONICAL_CORE_AGENT_ORDER` in `agent-priority-order.ts` controls object key insertion order in the agent map produced by `applyAgentConfig`.
-2. `installAgentSortShim()` in `src/shared/agent-sort-shim.ts` narrows `Array.prototype.toSorted` and `Array.prototype.sort` so that whenever the sorted array contains two or more agent objects whose `.name` matches a canonical core display name, OpenCode's `Agent.list()` (and any other sort site) returns the canonical order. The shim is installed once at plugin entry, before any agent registration.
+1. `DEFAULT_AGENT_ORDER` in `src/shared/agent-ordering.ts` supplies the fallback order used when `agent_order` is absent or incomplete.
+2. `reorderAgentsByPriority()` in `agent-priority-order.ts` controls object key insertion order in the agent map produced by `applyAgentConfig`.
+3. `installAgentSortShim()` in `src/shared/agent-sort-shim.ts` narrows `Array.prototype.toSorted` and `Array.prototype.sort` so that whenever the sorted array contains two or more ranked agent objects, OpenCode's `Agent.list()` (and any other sort site) returns the active configured/default order. The shim is installed once at plugin entry, before any agent registration, and its rank map is updated after plugin config loads.
 
 ### Why a Sort Shim
 
@@ -18,7 +19,7 @@ OpenCode 1.4.x sorts agents purely by `agent.name` via Remeda `sortBy`, which us
 - Removing the prefix and relying on insertion order alone falls back to alphabetical Atlas → Hephaestus → Prometheus → Sisyphus.
 
 The sort shim resolves this by intercepting only the narrow case it cares about, with strict activation guards to prevent collateral damage from a global prototype patch:
-- The activation predicate (`isAgentArray`) requires `arr.length >= 2`, every element is a non-null object with a string `.name`, and at least 2 elements have a `.name` matching one of the four canonical core display names. This rejects mixed-type arrays (numbers, strings, plain objects without `.name`) so unrelated `.sort()` / `.toSorted()` calls execute native semantics.
+- The activation predicate (`isAgentArray`) requires `arr.length >= 2`, every element is a non-null object with a string `.name`, and at least 2 elements have a `.name` ranked by the active order. This rejects mixed-type arrays (numbers, strings, plain objects without `.name`) so unrelated `.sort()` / `.toSorted()` calls execute native semantics.
 - The comparator never throws on mixed input — it defensively extracts `.name` and falls back to the user-supplied `compareFn`.
 - `installAgentSortShim()` is idempotent.
 
@@ -34,7 +35,7 @@ Agent ordering has caused 15+ commits, 8+ PRs, and multiple reverts. Notable mil
 DO NOT introduce:
 - ZWSP, U+2060, U+00AD, ANSI escape, or any other invisible / control character in agent names, display names, or object keys.
 - ASCII spaces or other visible sort prefixes on agent names.
-- Alternative ordering constants outside `CANONICAL_CORE_AGENT_ORDER`.
+- Alternative ordering constants outside `DEFAULT_AGENT_ORDER` / `CANONICAL_CORE_AGENT_ORDER`, or ordering code that bypasses `validateAgentOrder`.
 - Object.entries() iteration-order dependencies.
 - Agent name string comparisons that skip `getAgentConfigKey` / `stripInvisibleAgentCharacters` (legacy ZWSP-baked data must keep resolving).
 

src/plugin-handlers/agent-config-handler.ts

@@ -395,6 +395,7 @@ export async function applyAgentConfig(params: {
     );
     params.config.agent = reorderAgentsByPriority(
       params.config.agent as Record<string, unknown>,
+      params.pluginConfig.agent_order,
     );
   }
 

src/plugin-handlers/agent-priority-order.test.ts

@@ -65,6 +65,48 @@ describe("agent-priority-order", () => {
         expect(keys[3]).toBe(atlas)
       })
 
+      test("#when custom agent order is provided #then follows configured core ordering", () => {
+        // given
+        const agents: Record<string, unknown> = {
+          [atlas]: { name: "atlas" },
+          [prometheus]: { name: "prometheus" },
+          [hephaestus]: { name: "hephaestus" },
+          [sisyphus]: { name: "sisyphus" },
+        }
+
+        // when
+        const result = reorderAgentsByPriority(agents, [
+          "hephaestus",
+          "sisyphus",
+          "prometheus",
+          "atlas",
+        ])
+
+        // then
+        expect(Object.keys(result)).toEqual([hephaestus, sisyphus, prometheus, atlas])
+      })
+
+      test("#when custom agent order contains invalid entries #then ignores them and keeps valid/default ordering", () => {
+        // given
+        const agents: Record<string, unknown> = {
+          [atlas]: { name: "atlas" },
+          [prometheus]: { name: "prometheus" },
+          [hephaestus]: { name: "hephaestus" },
+          [sisyphus]: { name: "sisyphus" },
+        }
+
+        // when
+        const result = reorderAgentsByPriority(agents, [
+          "not-real",
+          "atlas",
+          "hephaestus",
+          "atlas",
+        ])
+
+        // then
+        expect(Object.keys(result)).toEqual([atlas, hephaestus, sisyphus, prometheus])
+      })
+
       test("#when core agents mixed with non-core #then core agents come first in canonical order", () => {
         // given: mixed order with non-core agents interleaved
         const agents: Record<string, unknown> = {
@@ -199,6 +241,21 @@ describe("agent-priority-order", () => {
         expect(result[atlas]).toEqual({ name: "atlas", mode: "primary", order: 4 })
       })
 
+      test("#when custom agent order is provided #then injects matching order fields", () => {
+        // given
+        const agents: Record<string, unknown> = {
+          [sisyphus]: { name: "sisyphus", mode: "primary" },
+          [hephaestus]: { name: "hephaestus", mode: "primary" },
+        }
+
+        // when
+        const result = reorderAgentsByPriority(agents, ["hephaestus", "sisyphus"])
+
+        // then
+        expect(result[hephaestus]).toEqual({ name: "hephaestus", mode: "primary", order: 1 })
+        expect(result[sisyphus]).toEqual({ name: "sisyphus", mode: "primary", order: 2 })
+      })
+
       test("#when core agent is non-object #then leaves value unchanged", () => {
         // given
         const agents: Record<string, unknown> = {

src/plugin-handlers/agent-priority-order.ts

@@ -1,35 +1,16 @@
-import { getAgentListDisplayName } from "../shared/agent-display-names"
+import { DEFAULT_AGENT_ORDER, resolveAgentOrderDisplayNames } from "../shared/agent-ordering"
 
 /**
- * CRITICAL: This is the ONLY source of truth for core agent ordering.
- * The order is: sisyphus → hephaestus → prometheus → atlas
+ * Default source of truth for core agent ordering.
+ * The default order is: sisyphus → hephaestus → prometheus → atlas.
  *
- * DO NOT CHANGE THIS ORDER. Any PR attempting to modify this order
- * or introduce alternative ordering mechanisms (ZWSP prefixes, sort
- * shims, etc.) will be rejected.
+ * User config may override the runtime order through `agent_order`; missing
+ * core agents still fall back to this default order. Do not reintroduce sort
+ * key prefixes or a second ordering constant.
  *
  * See: src/plugin-handlers/AGENTS.md for architectural context.
  */
-export const CANONICAL_CORE_AGENT_ORDER = [
-  "sisyphus",
-  "hephaestus",
-  "prometheus",
-  "atlas",
-] as const
-
-type CoreAgentName = (typeof CANONICAL_CORE_AGENT_ORDER)[number]
-
-const CORE_AGENT_ORDER: ReadonlyArray<{
-  configKey: CoreAgentName
-  displayName: string
-  order: number
-}> = CANONICAL_CORE_AGENT_ORDER.map((configKey, index) => ({
-  configKey,
-  displayName: getAgentListDisplayName(configKey),
-  order: index + 1,
-}))
-
-const CORE_DISPLAY_NAMES = new Set(CORE_AGENT_ORDER.map((a) => a.displayName))
+export const CANONICAL_CORE_AGENT_ORDER = DEFAULT_AGENT_ORDER
 
 function injectOrderField(agentConfig: unknown, order: number): unknown {
   if (typeof agentConfig === "object" && agentConfig !== null) {
@@ -40,13 +21,15 @@ function injectOrderField(agentConfig: unknown, order: number): unknown {
 
 export function reorderAgentsByPriority(
   agents: Record<string, unknown>,
+  agentOrder?: readonly string[],
 ): Record<string, unknown> {
   const ordered: Record<string, unknown> = {}
   const seen = new Set<string>()
+  const orderedDisplayNames = resolveAgentOrderDisplayNames(agentOrder)
 
-  for (const { displayName, order } of CORE_AGENT_ORDER) {
+  for (const [index, displayName] of orderedDisplayNames.entries()) {
     if (Object.prototype.hasOwnProperty.call(agents, displayName)) {
-      ordered[displayName] = injectOrderField(agents[displayName], order)
+      ordered[displayName] = injectOrderField(agents[displayName], index + 1)
       seen.add(displayName)
     }
   }

src/shared/agent-ordering.ts

@@ -0,0 +1,61 @@
+import { AGENT_DISPLAY_NAMES, getAgentConfigKey, getAgentListDisplayName } from "./agent-display-names"
+
+export const DEFAULT_AGENT_ORDER = [
+  "sisyphus",
+  "hephaestus",
+  "prometheus",
+  "atlas",
+] as const
+
+export type AgentOrderValidation = {
+  order: string[]
+  invalid: string[]
+  duplicates: string[]
+}
+
+const KNOWN_AGENT_KEYS = new Set(Object.keys(AGENT_DISPLAY_NAMES))
+
+function appendUnique(target: string[], value: string): void {
+  if (!target.includes(value)) {
+    target.push(value)
+  }
+}
+
+export function validateAgentOrder(agentOrder: readonly string[] | undefined): AgentOrderValidation {
+  const order: string[] = []
+  const invalid: string[] = []
+  const duplicates: string[] = []
+  const seen = new Set<string>()
+
+  for (const rawName of agentOrder ?? []) {
+    const trimmed = rawName.trim()
+    if (trimmed.length === 0) {
+      invalid.push(rawName)
+      continue
+    }
+
+    const configKey = getAgentConfigKey(trimmed)
+    if (!KNOWN_AGENT_KEYS.has(configKey)) {
+      invalid.push(rawName)
+      continue
+    }
+
+    if (seen.has(configKey)) {
+      duplicates.push(rawName)
+      continue
+    }
+
+    seen.add(configKey)
+    order.push(configKey)
+  }
+
+  for (const configKey of DEFAULT_AGENT_ORDER) {
+    appendUnique(order, configKey)
+  }
+
+  return { order, invalid, duplicates }
+}
+
+export function resolveAgentOrderDisplayNames(agentOrder: readonly string[] | undefined): string[] {
+  return validateAgentOrder(agentOrder).order.map((configKey) => getAgentListDisplayName(configKey))
+}

src/shared/agent-sort-shim.test.ts

@@ -1,8 +1,8 @@
 /// <reference types="bun-types" />
 
-import { beforeAll, describe, expect, test } from "bun:test"
+import { afterEach, beforeAll, describe, expect, test } from "bun:test"
 
-import { installAgentSortShim } from "./agent-sort-shim"
+import { installAgentSortShim, setAgentSortOrder } from "./agent-sort-shim"
 import { AGENT_DISPLAY_NAMES } from "./agent-display-names"
 
 type AgentListItem = {
@@ -10,15 +10,26 @@ type AgentListItem = {
   default_agent?: boolean
 }
 
+declare global {
+  interface Array<T> {
+    toSorted(compareFn?: (a: T, b: T) => number): T[]
+  }
+}
+
 describe("agent-sort-shim", () => {
   beforeAll(() => {
     installAgentSortShim()
   })
 
+  afterEach(() => {
+    setAgentSortOrder(undefined)
+  })
+
   describe("#given an array of all 4 core agent objects in random order", () => {
     describe("#when toSorted with alphabetical compareFn", () => {
       test("#then returns canonical sisyphus->hephaestus->prometheus->atlas order", () => {
         // given
+        setAgentSortOrder(undefined)
         const sisyphus = { name: "Sisyphus - Ultraworker" }
         const hephaestus = { name: "Hephaestus - Deep Agent" }
         const prometheus = { name: "Prometheus - Plan Builder" }
@@ -31,6 +42,22 @@ describe("agent-sort-shim", () => {
         // then
         expect(result).toEqual([sisyphus, hephaestus, prometheus, atlas])
       })
+
+      test("#then follows configured core agent order", () => {
+        // given
+        setAgentSortOrder(["hephaestus", "sisyphus", "prometheus", "atlas"])
+        const sisyphus = { name: "Sisyphus - Ultraworker" }
+        const hephaestus = { name: "Hephaestus - Deep Agent" }
+        const prometheus = { name: "Prometheus - Plan Builder" }
+        const atlas = { name: "Atlas - Plan Executor" }
+        const input = [atlas, prometheus, hephaestus, sisyphus]
+
+        // when
+        const result = input.toSorted((a, b) => a.name.localeCompare(b.name))
+
+        // then
+        expect(result).toEqual([hephaestus, sisyphus, prometheus, atlas])
+      })
     })
   })
 

src/shared/agent-sort-shim.ts

@@ -3,10 +3,9 @@
  *
  * OpenCode 1.4.x ignores the agent `order` field (sst/opencode#19127) and
  * sorts the agent list by `agent.name` via Remeda `sortBy(x => x.name, "asc")`
- * at packages/opencode/src/agent/agent.ts. Without intervention, the four
- * core agents collapse into Atlas -> Hephaestus -> Prometheus -> Sisyphus,
- * which inverts the canonical sisyphus -> hephaestus -> prometheus -> atlas
- * order this project ships.
+ * at packages/opencode/src/agent/agent.ts. Without intervention, core agents
+ * collapse into name order, which can invert the default sisyphus -> hephaestus
+ * -> prometheus -> atlas order or a user's configured `agent_order`.
  *
  * Earlier attempts to bias the sort key with invisible characters (ZWSP,
  * U+2060 WORD JOINER, U+00AD SOFT HYPHEN, ANSI escape) caused visible-gap
@@ -17,22 +16,21 @@
  *   1. `isAgentArray` rejects any array element that is null, non-object, or
  *      lacks a string `name`, eliminating the throw-on-mixed-array failure
  *      mode that closed the original PR.
- *   2. The activation predicate requires >= 2 elements whose `.name` is one
- *      of the four canonical core display names, so unrelated `.sort()` and
- *      `.toSorted()` calls (string arrays, number arrays, generic objects)
- *      execute native behavior unchanged.
+ *   2. The activation predicate requires >= 2 elements whose `.name` is ranked
+ *      by the active agent order, so unrelated `.sort()` and `.toSorted()` calls
+ *      (string arrays, number arrays, generic objects) execute native behavior
+ *      unchanged.
  *
  * Remove this shim once OpenCode honors the agent `order` field
  * (sst/opencode#19127).
  */
 
-import { CANONICAL_CORE_AGENT_ORDER } from "../plugin-handlers/agent-priority-order"
-import { AGENT_DISPLAY_NAMES } from "./agent-display-names"
+import { DEFAULT_AGENT_ORDER, resolveAgentOrderDisplayNames } from "./agent-ordering"
+import { getAgentListDisplayName } from "./agent-display-names"
 
-const AGENT_RANK: ReadonlyMap<string, number> = new Map(
-  CANONICAL_CORE_AGENT_ORDER.map(
-    (configKey, index): [string, number] => [AGENT_DISPLAY_NAMES[configKey], index + 1],
-  ),
+let agentRank: ReadonlyMap<string, number> = createAgentRank(undefined)
+const AGENT_ARRAY_SENTINELS = new Set(
+  DEFAULT_AGENT_ORDER.map((configKey) => getAgentListDisplayName(configKey)),
 )
 
 const UNRANKED = Number.MAX_SAFE_INTEGER
@@ -51,7 +49,7 @@ function isAgentArray(arr: ReadonlyArray<unknown>): boolean {
     if (element === null || typeof element !== "object") return false
     const name = (element as { name?: unknown }).name
     if (typeof name !== "string") return false
-    if (AGENT_RANK.has(name)) rankedCount++
+    if (AGENT_ARRAY_SENTINELS.has(name)) rankedCount++
   }
 
   return rankedCount >= 2
@@ -62,8 +60,8 @@ function agentComparator(
   b: unknown,
   fallback: ((a: unknown, b: unknown) => number) | undefined,
 ): number {
-  const aRank = AGENT_RANK.get(extractAgentName(a)) ?? UNRANKED
-  const bRank = AGENT_RANK.get(extractAgentName(b)) ?? UNRANKED
+  const aRank = agentRank.get(extractAgentName(a)) ?? UNRANKED
+  const bRank = agentRank.get(extractAgentName(b)) ?? UNRANKED
 
   if (aRank !== bRank) return aRank - bRank
   if (fallback) return fallback(a, b)
@@ -72,6 +70,18 @@ function agentComparator(
 
 let installed = false
 
+function createAgentRank(agentOrder: readonly string[] | undefined): ReadonlyMap<string, number> {
+  return new Map(
+    resolveAgentOrderDisplayNames(agentOrder).map(
+      (displayName, index): [string, number] => [displayName, index + 1],
+    ),
+  )
+}
+
+export function setAgentSortOrder(agentOrder: readonly string[] | undefined): void {
+  agentRank = createAgentRank(agentOrder)
+}
+
 export function installAgentSortShim(): void {
   if (installed) return