Function TestInjectTools_CacheBreakpoints

intercept/messages/base_test.go:381–488

(t *testing.T)

}

func TestInjectTools_CacheBreakpoints(t *testing.T) {
	t.Parallel()

	t.Run("cache control preserved when no tools to inject", func(t *testing.T) {
		t.Parallel()

		// Request has existing tool with cache control, but no tools to inject.
		i := &interceptionBase{
			reqPayload: mustMessagesPayload(t, `{"tools":[`+
				`{"name":"existing_tool","type":"custom","input_schema":{"type":"object","properties":{}},"cache_control":{"type":"ephemeral"}}]}`),
			mcpProxy: &mockServerProxier{tools: nil},
			logger:   slog.Make(),
		}

		i.injectTools()

		// Cache control should remain untouched since no tools were injected.
		toolItems := gjson.GetBytes(i.reqPayload, "tools").Array()
		require.Len(t, toolItems, 1)
		require.Equal(t, "existing_tool", toolItems[0].Get("name").String())
		require.Equal(t, string(constant.ValueOf[constant.Ephemeral]()), toolItems[0].Get("cache_control.type").String())
	})

	t.Run("cache control breakpoint is preserved by prepending injected tools", func(t *testing.T) {
		t.Parallel()

		// Request has existing tool with cache control.
		i := &interceptionBase{
			reqPayload: mustMessagesPayload(t, `{"tools":[`+
				`{"name":"existing_tool","type":"custom","input_schema":{"type":"object","properties":{}},"cache_control":{"type":"ephemeral"}}]}`),
			mcpProxy: &mockServerProxier{
				tools: []*mcp.Tool{
					{ID: "injected_tool", Name: "injected", Description: "Injected tool"},
				},
			},
			logger: slog.Make(),
		}

		i.injectTools()

		toolItems := gjson.GetBytes(i.reqPayload, "tools").Array()
		require.Len(t, toolItems, 2)
		// Injected tools are prepended.
		require.Equal(t, "injected_tool", toolItems[0].Get("name").String())
		require.Empty(t, toolItems[0].Get("cache_control.type").String())
		// Original tool's cache control should be preserved at the end.
		require.Equal(t, "existing_tool", toolItems[1].Get("name").String())
		require.Equal(t, string(constant.ValueOf[constant.Ephemeral]()), toolItems[1].Get("cache_control.type").String())
	})

	// The cache breakpoint SHOULD be on the final tool, but may not be; we must preserve that intention.
	t.Run("cache control breakpoint in non-standard location is preserved", func(t *testing.T) {
		t.Parallel()

		// Request has multiple tools with cache control breakpoints.
		i := &interceptionBase{
			reqPayload: mustMessagesPayload(t, `{"tools":[`+
				`{"name":"tool_with_cache_1","type":"custom","input_schema":{"type":"object","properties":{}},"cache_control":{"type":"ephemeral"}},`+