feat(cli): add doctor check for model resolution

Add new 'model-resolution' check to diagnose model fallback chain health. Validates that configured agents and categories can resolve to available models, surfacing misconfiguration early.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/cli/doctor/checks/model-resolution.test.ts

@@ -0,0 +1,139 @@
+import { describe, it, expect, beforeEach, afterEach, spyOn, mock } from "bun:test"
+
+describe("model-resolution check", () => {
+  describe("getModelResolutionInfo", () => {
+    // #given: Model requirements are defined in model-requirements.ts
+    // #when: Getting model resolution info
+    // #then: Returns info for all agents and categories with their provider chains
+
+    it("returns agent requirements with provider chains", async () => {
+      const { getModelResolutionInfo } = await import("./model-resolution")
+
+      const info = getModelResolutionInfo()
+
+      // #then: Should have agent entries
+      const sisyphus = info.agents.find((a) => a.name === "Sisyphus")
+      expect(sisyphus).toBeDefined()
+      expect(sisyphus!.requirement.fallbackChain[0]?.model).toBe("claude-opus-4-5")
+      expect(sisyphus!.requirement.fallbackChain[0]?.providers).toContain("anthropic")
+      expect(sisyphus!.requirement.fallbackChain[0]?.providers).toContain("github-copilot")
+    })
+
+    it("returns category requirements with provider chains", async () => {
+      const { getModelResolutionInfo } = await import("./model-resolution")
+
+      const info = getModelResolutionInfo()
+
+      // #then: Should have category entries
+      const visual = info.categories.find((c) => c.name === "visual-engineering")
+      expect(visual).toBeDefined()
+      expect(visual!.requirement.fallbackChain[0]?.model).toBe("gemini-3-pro-preview")
+      expect(visual!.requirement.fallbackChain[0]?.providers).toContain("google")
+    })
+  })
+
+  describe("getModelResolutionInfoWithOverrides", () => {
+    // #given: User has overrides in oh-my-opencode.json
+    // #when: Getting resolution info with config
+    // #then: Shows user override in Step 1 position
+
+    it("shows user override for agent when configured", async () => {
+      const { getModelResolutionInfoWithOverrides } = await import("./model-resolution")
+
+      // #given: User has override for oracle agent
+      const mockConfig = {
+        agents: {
+          oracle: { model: "anthropic/claude-opus-4-5" },
+        },
+      }
+
+      const info = getModelResolutionInfoWithOverrides(mockConfig)
+
+      // #then: Oracle should show the override
+      const oracle = info.agents.find((a) => a.name === "oracle")
+      expect(oracle).toBeDefined()
+      expect(oracle!.userOverride).toBe("anthropic/claude-opus-4-5")
+      expect(oracle!.effectiveResolution).toBe("User override: anthropic/claude-opus-4-5")
+    })
+
+    it("shows user override for category when configured", async () => {
+      const { getModelResolutionInfoWithOverrides } = await import("./model-resolution")
+
+      // #given: User has override for visual-engineering category
+      const mockConfig = {
+        categories: {
+          "visual-engineering": { model: "openai/gpt-5.2" },
+        },
+      }
+
+      const info = getModelResolutionInfoWithOverrides(mockConfig)
+
+      // #then: visual-engineering should show the override
+      const visual = info.categories.find((c) => c.name === "visual-engineering")
+      expect(visual).toBeDefined()
+      expect(visual!.userOverride).toBe("openai/gpt-5.2")
+      expect(visual!.effectiveResolution).toBe("User override: openai/gpt-5.2")
+    })
+
+    it("shows provider fallback when no override exists", async () => {
+      const { getModelResolutionInfoWithOverrides } = await import("./model-resolution")
+
+      // #given: No overrides configured
+      const mockConfig = {}
+
+      const info = getModelResolutionInfoWithOverrides(mockConfig)
+
+      // #then: Should show provider fallback chain
+      const sisyphus = info.agents.find((a) => a.name === "Sisyphus")
+      expect(sisyphus).toBeDefined()
+      expect(sisyphus!.userOverride).toBeUndefined()
+      expect(sisyphus!.effectiveResolution).toContain("Provider fallback:")
+      expect(sisyphus!.effectiveResolution).toContain("anthropic")
+    })
+  })
+
+  describe("checkModelResolution", () => {
+    // #given: Doctor check is executed
+    // #when: Running the model resolution check
+    // #then: Returns pass with details showing resolution flow
+
+    it("returns pass status with agent and category counts", async () => {
+      const { checkModelResolution } = await import("./model-resolution")
+
+      const result = await checkModelResolution()
+
+      // #then: Should pass and show counts
+      expect(result.status).toBe("pass")
+      expect(result.message).toMatch(/\d+ agents?, \d+ categories?/)
+    })
+
+    it("includes resolution details in verbose mode details array", async () => {
+      const { checkModelResolution } = await import("./model-resolution")
+
+      const result = await checkModelResolution()
+
+      // #then: Details should contain agent/category resolution info
+      expect(result.details).toBeDefined()
+      expect(result.details!.length).toBeGreaterThan(0)
+      // Should have Current Models header and sections
+      expect(result.details!.some((d) => d.includes("Current Models"))).toBe(true)
+      expect(result.details!.some((d) => d.includes("Agents:"))).toBe(true)
+      expect(result.details!.some((d) => d.includes("Categories:"))).toBe(true)
+      // Should have legend
+      expect(result.details!.some((d) => d.includes("user override"))).toBe(true)
+    })
+  })
+
+  describe("getModelResolutionCheckDefinition", () => {
+    it("returns valid check definition", async () => {
+      const { getModelResolutionCheckDefinition } = await import("./model-resolution")
+
+      const def = getModelResolutionCheckDefinition()
+
+      expect(def.id).toBe("model-resolution")
+      expect(def.name).toBe("Model Resolution")
+      expect(def.category).toBe("configuration")
+      expect(typeof def.check).toBe("function")
+    })
+  })
+})