Function TestGetMessages_CacheControlWithSummary

pkg/session/session_test.go:207–253

(t *testing.T)

}

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

	// Caching contract pinned by this test:
	//
	//   - The last invariant system message gets a cache-control marker.
	//   - The last caller-supplied extra (typically turn_start hook output)
	//     ALSO gets a cache-control marker so stable per-session/per-day
	//     extras (AddPromptFiles, AddEnvironmentInfo) participate in
	//     prompt caching. This matches the prior
	//     buildContextSpecificSystemMessages caching behavior.
	//   - Summary and conversation messages are not cache-controlled.
	testAgent := agent.New("root", "instructions",
		agent.WithToolSets(todoToolSet(t)),
	)

	s := New()
	s.Messages = append(s.Messages, Item{Summary: "Test summary"})

	extra := chat.Message{
		Role:    chat.MessageRoleSystem,
		Content: "Today's date: 2026-04-25",
	}
	messages := s.GetMessages(testAgent, extra)

	var checkpointIndices []int
	for i, msg := range messages {
		if msg.Role == chat.MessageRoleSystem && msg.CacheControl {
			checkpointIndices = append(checkpointIndices, i)
		}
	}

	require.Len(t, checkpointIndices, 2,
		"invariant and last-extra messages should each be cache-controlled")

	// Checkpoint #1: last invariant message (toolset instructions).
	assert.Contains(t, messages[checkpointIndices[0]].Content, "Todo Tools",
		"checkpoint #1 must land on the last invariant message")

	// Checkpoint #2: last extra (the date system message).
	assert.Equal(t, extra.Content, messages[checkpointIndices[1]].Content,
		"checkpoint #2 must land on the last extra system message")

	// The extra must come AFTER the invariant block.
	assert.Greater(t, checkpointIndices[1], checkpointIndices[0],
		"extras must come AFTER the invariant cache checkpoint")
}

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