fix(model-availability): prefer exact model ID match in fuzzyMatchModel (#1460)

* fix(model-availability): prefer exact model ID match in fuzzyMatchModel

* fix(model-availability): use filter+shortest for multi-provider tie-break

- Change Priority 2 from find() to filter()+reduce()
- Preserves shortest-match tie-break when multiple providers share model ID
- Add test for multi-provider same model ID case
- Addresses Oracle review feedback

src/shared/model-availability.test.ts

@@ -277,6 +277,42 @@ describe("fuzzyMatchModel", () => {
 		expect(result).toBe("anthropic/claude-opus-4-5")
 	})
 
+	// given available models with similar model IDs (e.g., glm-4.7 and glm-4.7-free)
+	// when searching for the longer variant (glm-4.7-free)
+	// then return exact model ID match, not the shorter one
+	it("should prefer exact model ID match over shorter substring match", () => {
+		const available = new Set([
+			"zai-coding-plan/glm-4.7",
+			"zai-coding-plan/glm-4.7-free",
+		])
+		const result = fuzzyMatchModel("glm-4.7-free", available)
+		expect(result).toBe("zai-coding-plan/glm-4.7-free")
+	})
+
+	// given available models with similar model IDs
+	// when searching for the shorter variant
+	// then return the shorter match (existing behavior preserved)
+	it("should still prefer shorter match when searching for shorter variant", () => {
+		const available = new Set([
+			"zai-coding-plan/glm-4.7",
+			"zai-coding-plan/glm-4.7-free",
+		])
+		const result = fuzzyMatchModel("glm-4.7", available)
+		expect(result).toBe("zai-coding-plan/glm-4.7")
+	})
+
+	// given same model ID from multiple providers
+	// when searching for exact model ID
+	// then return shortest full string (preserves tie-break behavior)
+	it("should use shortest tie-break when multiple providers have same model ID", () => {
+		const available = new Set([
+			"opencode/gpt-5.2",
+			"openai/gpt-5.2",
+		])
+		const result = fuzzyMatchModel("gpt-5.2", available)
+		expect(result).toBe("openai/gpt-5.2")
+	})
+
 	// given available models with multiple providers
 	// when multiple providers are specified
 	// then search all specified providers

src/shared/model-availability.ts

@@ -72,14 +72,29 @@ export function fuzzyMatchModel(
 		return null
 	}
 
-	// Priority 1: Exact match (normalized)
+	// Priority 1: Exact match (normalized full model string)
 	const exactMatch = matches.find((model) => normalizeModelName(model) === targetNormalized)
 	if (exactMatch) {
 		log("[fuzzyMatchModel] exact match found", { exactMatch })
 		return exactMatch
 	}
 
-	// Priority 2: Shorter model name (more specific)
+	// Priority 2: Exact model ID match (part after provider/)
+	// This ensures "glm-4.7-free" matches "zai-coding-plan/glm-4.7-free" over "zai-coding-plan/glm-4.7"
+	// Use filter + shortest to handle multi-provider cases (e.g., openai/gpt-5.2 + opencode/gpt-5.2)
+	const exactModelIdMatches = matches.filter((model) => {
+		const modelId = model.split("/").slice(1).join("/")
+		return normalizeModelName(modelId) === targetNormalized
+	})
+	if (exactModelIdMatches.length > 0) {
+		const result = exactModelIdMatches.reduce((shortest, current) =>
+			current.length < shortest.length ? current : shortest,
+		)
+		log("[fuzzyMatchModel] exact model ID match found", { result, candidateCount: exactModelIdMatches.length })
+		return result
+	}
+
+	// Priority 3: Shorter model name (more specific, fallback for partial matches)
 	const result = matches.reduce((shortest, current) =>
 		current.length < shortest.length ? current : shortest,
 	)