Fix runtime provider override leakage across source handoff

packages/coding-agent/CHANGELOG.md

@@ -25,7 +25,7 @@
 - Fixed edit streaming preview updates to cancel obsolete in-flight computations and avoid rendering stale previews as args change
 - Fixed Mermaid fenced markdown rendering in assistant messages on terminals without image protocol support ([#650](https://github.com/can1357/oh-my-pi/issues/650))
 - Fixed SQLite `read` helper queries to reject `where=` clauses with SQL control syntax that could override the structured selector's pagination; raw SQL remains available through `q=SELECT ...`
-- Fixed `models` provider transport overrides so `headers`-only entries apply without requiring `baseUrl`, including runtime `registerProvider()` overrides that now persist across `refresh()` / `refreshProvider()` and preserve existing `baseUrl` on subsequent headers-only updates
+- Fixed `models` provider transport overrides so `headers`-only entries apply without requiring `baseUrl`, including runtime `registerProvider()` overrides that now persist across `refresh()` / `refreshProvider()`, preserve existing `baseUrl` on subsequent headers-only updates, and clear stale transport overrides when a provider is re-registered under a different extension source
 
 ## [14.2.0] - 2026-04-23
 

packages/coding-agent/src/config/model-registry.ts

@@ -2035,6 +2035,7 @@ export class ModelRegistry {
 				if (previousProviders && previousProviders.size === 0) {
 					this.#runtimeProvidersBySource.delete(previousSourceId);
 				}
+				this.#runtimeProviderOverrides.delete(providerName);
 			}
 			const sourceProviders = this.#runtimeProvidersBySource.get(sourceId) ?? new Set<string>();
 			sourceProviders.add(providerName);

packages/coding-agent/test/model-registry-runtime-provider.test.ts

@@ -382,6 +382,54 @@ describe("ModelRegistry runtime provider registration", () => {
 		expect(modelAfterProviderRefresh?.headers?.[runtimeHeader]).toBe("runtime-header");
 	});
 
+	test("provider source handoff does not retain previous source transport overrides", async () => {
+		const registry = new ModelRegistry(authStorage, modelsJsonPath);
+		const providerName = "shared-runtime-provider";
+		const leakedHeader = "X-Old-Source-Header";
+		const sourceBBaseUrl = "https://source-b.example.com/v1";
+
+		registry.registerProvider(
+			providerName,
+			{
+				baseUrl: "https://source-a.example.com/v1",
+				apiKey: "KEY_A",
+				api: "openai-completions",
+				models: [{ ...baseModel, id: "model-a" }],
+			},
+			"ext://a",
+		);
+		registry.registerProvider(
+			providerName,
+			{ baseUrl: "https://override-a.example.com/v1", headers: { [leakedHeader]: "from-source-a" } },
+			"ext://a",
+		);
+		registry.registerProvider(
+			providerName,
+			{
+				baseUrl: sourceBBaseUrl,
+				apiKey: "KEY_B",
+				api: "openai-completions",
+				models: [{ ...baseModel, id: "model-b" }],
+			},
+			"ext://b",
+		);
+
+		expect(registry.find(providerName, "model-a")).toBeUndefined();
+		const modelAfterHandoff = registry.find(providerName, "model-b");
+		expect(modelAfterHandoff?.baseUrl).toBe(sourceBBaseUrl);
+		expect(modelAfterHandoff?.headers?.[leakedHeader]).toBeUndefined();
+
+		await registry.refresh("offline");
+		const modelAfterRefresh = registry.find(providerName, "model-b");
+		expect(modelAfterRefresh?.baseUrl).toBe(sourceBBaseUrl);
+		expect(modelAfterRefresh?.headers?.[leakedHeader]).toBeUndefined();
+
+		await registry.refreshProvider(providerName, "offline");
+		const modelAfterProviderRefresh = registry.find(providerName, "model-b");
+		expect(modelAfterProviderRefresh?.baseUrl).toBe(sourceBBaseUrl);
+		expect(modelAfterProviderRefresh?.headers?.[leakedHeader]).toBeUndefined();
+	});
+
 	test("multiple extension providers survive refresh independently", async () => {
 		const registry = new ModelRegistry(authStorage, modelsJsonPath);