fix(agent-variant): resolve variant based on current model, not static config (#1179)

src/index.ts

@@ -40,7 +40,7 @@ import {
   contextCollector,
   createContextInjectorMessagesTransformHook,
 } from "./features/context-injector";
-import { applyAgentVariant, resolveAgentVariant } from "./shared/agent-variant";
+import { applyAgentVariant, resolveAgentVariant, resolveVariantForModel } from "./shared/agent-variant";
 import { createFirstMessageVariantGate } from "./shared/first-message-variant";
 import {
   discoverUserClaudeSkills,
@@ -384,13 +384,22 @@ const OhMyOpenCodePlugin: Plugin = async (ctx) => {
 
       const message = (output as { message: { variant?: string } }).message
       if (firstMessageVariantGate.shouldOverride(input.sessionID)) {
-        const variant = resolveAgentVariant(pluginConfig, input.agent)
+        const variant = input.model && input.agent
+          ? resolveVariantForModel(pluginConfig, input.agent, input.model)
+          : resolveAgentVariant(pluginConfig, input.agent)
         if (variant !== undefined) {
           message.variant = variant
         }
         firstMessageVariantGate.markApplied(input.sessionID)
       } else {
-        applyAgentVariant(pluginConfig, input.agent, message)
+        if (input.model && input.agent && message.variant === undefined) {
+          const variant = resolveVariantForModel(pluginConfig, input.agent, input.model)
+          if (variant !== undefined) {
+            message.variant = variant
+          }
+        } else {
+          applyAgentVariant(pluginConfig, input.agent, message)
+        }
       }
 
       await keywordDetector?.["chat.message"]?.(input, output);

src/shared/agent-variant.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, test } from "bun:test"
 import type { OhMyOpenCodeConfig } from "../config"
-import { applyAgentVariant, resolveAgentVariant } from "./agent-variant"
+import { applyAgentVariant, resolveAgentVariant, resolveVariantForModel } from "./agent-variant"
 
 describe("resolveAgentVariant", () => {
   test("returns undefined when agent name missing", () => {
@@ -81,3 +81,117 @@ describe("applyAgentVariant", () => {
     expect(message.variant).toBe("max")
   })
 })
+
+describe("resolveVariantForModel", () => {
+  test("returns correct variant for anthropic provider", () => {
+    // #given
+    const config = {} as OhMyOpenCodeConfig
+    const model = { providerID: "anthropic", modelID: "claude-opus-4-5" }
+
+    // #when
+    const variant = resolveVariantForModel(config, "sisyphus", model)
+
+    // #then
+    expect(variant).toBe("max")
+  })
+
+  test("returns correct variant for openai provider", () => {
+    // #given
+    const config = {} as OhMyOpenCodeConfig
+    const model = { providerID: "openai", modelID: "gpt-5.2" }
+
+    // #when
+    const variant = resolveVariantForModel(config, "sisyphus", model)
+
+    // #then
+    expect(variant).toBe("medium")
+  })
+
+  test("returns undefined for provider with no variant in chain", () => {
+    // #given
+    const config = {} as OhMyOpenCodeConfig
+    const model = { providerID: "google", modelID: "gemini-3-pro" }
+
+    // #when
+    const variant = resolveVariantForModel(config, "sisyphus", model)
+
+    // #then
+    expect(variant).toBeUndefined()
+  })
+
+  test("returns undefined for provider not in chain", () => {
+    // #given
+    const config = {} as OhMyOpenCodeConfig
+    const model = { providerID: "unknown-provider", modelID: "some-model" }
+
+    // #when
+    const variant = resolveVariantForModel(config, "sisyphus", model)
+
+    // #then
+    expect(variant).toBeUndefined()
+  })
+
+  test("returns undefined for unknown agent", () => {
+    // #given
+    const config = {} as OhMyOpenCodeConfig
+    const model = { providerID: "anthropic", modelID: "claude-opus-4-5" }
+
+    // #when
+    const variant = resolveVariantForModel(config, "nonexistent-agent", model)
+
+    // #then
+    expect(variant).toBeUndefined()
+  })
+
+  test("returns variant for zai-coding-plan provider without variant", () => {
+    // #given
+    const config = {} as OhMyOpenCodeConfig
+    const model = { providerID: "zai-coding-plan", modelID: "glm-4.7" }
+
+    // #when
+    const variant = resolveVariantForModel(config, "sisyphus", model)
+
+    // #then
+    expect(variant).toBeUndefined()
+  })
+
+  test("falls back to category chain when agent has no requirement", () => {
+    // #given
+    const config = {
+      agents: {
+        "custom-agent": { category: "ultrabrain" },
+      },
+    } as OhMyOpenCodeConfig
+    const model = { providerID: "openai", modelID: "gpt-5.2-codex" }
+
+    // #when
+    const variant = resolveVariantForModel(config, "custom-agent", model)
+
+    // #then
+    expect(variant).toBe("xhigh")
+  })
+
+  test("returns correct variant for oracle agent with openai", () => {
+    // #given
+    const config = {} as OhMyOpenCodeConfig
+    const model = { providerID: "openai", modelID: "gpt-5.2" }
+
+    // #when
+    const variant = resolveVariantForModel(config, "oracle", model)
+
+    // #then
+    expect(variant).toBe("high")
+  })
+
+  test("returns correct variant for oracle agent with anthropic", () => {
+    // #given
+    const config = {} as OhMyOpenCodeConfig
+    const model = { providerID: "anthropic", modelID: "claude-opus-4-5" }
+
+    // #when
+    const variant = resolveVariantForModel(config, "oracle", model)
+
+    // #then
+    expect(variant).toBe("max")
+  })
+})

src/shared/agent-variant.ts

@@ -1,5 +1,6 @@
 import type { OhMyOpenCodeConfig } from "../config"
 import { findCaseInsensitive } from "./case-insensitive"
+import { AGENT_MODEL_REQUIREMENTS, CATEGORY_MODEL_REQUIREMENTS } from "./model-requirements"
 
 export function resolveAgentVariant(
   config: OhMyOpenCodeConfig,
@@ -29,6 +30,43 @@ export function resolveAgentVariant(
   return config.categories?.[categoryName]?.variant
 }
 
+export function resolveVariantForModel(
+  config: OhMyOpenCodeConfig,
+  agentName: string,
+  currentModel: { providerID: string; modelID: string },
+): string | undefined {
+  const agentRequirement = AGENT_MODEL_REQUIREMENTS[agentName]
+  if (agentRequirement) {
+    return findVariantInChain(agentRequirement.fallbackChain, currentModel.providerID)
+  }
+
+  const agentOverrides = config.agents as
+    | Record<string, { category?: string }>
+    | undefined
+  const agentOverride = agentOverrides ? findCaseInsensitive(agentOverrides, agentName) : undefined
+  const categoryName = agentOverride?.category
+  if (categoryName) {
+    const categoryRequirement = CATEGORY_MODEL_REQUIREMENTS[categoryName]
+    if (categoryRequirement) {
+      return findVariantInChain(categoryRequirement.fallbackChain, currentModel.providerID)
+    }
+  }
+
+  return undefined
+}
+
+function findVariantInChain(
+  fallbackChain: { providers: string[]; model: string; variant?: string }[],
+  providerID: string,
+): string | undefined {
+  for (const entry of fallbackChain) {
+    if (entry.providers.includes(providerID)) {
+      return entry.variant
+    }
+  }
+  return undefined
+}
+
 export function applyAgentVariant(
   config: OhMyOpenCodeConfig,
   agentName: string | undefined,