//! Verifies explicit and automatic context compaction behavior.
#[path = "support/fake_provider.rs"]
mod fake_provider;
#[path = "support/fixtures.rs"]
mod fixtures;
use std::{collections::HashMap, sync::Arc, time::Duration};
use cursor_server::{
cursor::prompting::{PromptAssets, PromptCompiler},
cursor::{
protocol::{connect, proto::agent::v1 as pb},
TransportCommand, TransportRegistry,
},
model::{
ContentPart, ConversationId, MessageContent, ModelConfigInput, ModelType, Origin,
ProjectedContent, Role, Usage, OPENAI_CHAT_ENDPOINT,
},
provider::{FinishReason, ModelEvent},
};
use prost::Message;
#[tokio::test]
async fn summarize_replaces_model_history_and_preserves_cursor_history() {
let (_directory, store) = fixtures::temp_store().await;
let model = store
.create_model(&ModelConfigInput {
sort_order: 0,
display_name: "Test Model".into(),
group_name: None,
model_type: ModelType::OpenAi,
base_url: "https://example.com/v1/chat/completions".into(),
use_full_url: true,
api_key: "test-key".into(),
tooltip_data: "Test Model".into(),
model_id: "test-model".into(),
reasoning_effort: None,
openai_endpoint: OPENAI_CHAT_ENDPOINT.into(),
openai_extra_params_enabled: false,
openai_extra_params: serde_json::json!({}),
custom_headers_enabled: false,
custom_headers: serde_json::json!({}),
anthropic_extra_params_enabled: false,
anthropic_extra_params: serde_json::json!({}),
context_window_tokens: None,
max_completion_tokens: None,
anthropic_max_tokens: None,
anthropic_thinking_effort: None,
thinking_budget_tokens: None,
})
.await
.unwrap();
let provider = fake_provider::FakeProvider::default();
provider.push(text_response("old answer", 4_000, 12));
provider.push(vec![
ModelEvent::Start {
model_call_id: "summary-call".into(),
},
ModelEvent::TextStart,
ModelEvent::TextDelta("Durable ".into()),
ModelEvent::TextDelta("summary".into()),
ModelEvent::TextEnd,
ModelEvent::Usage(Usage {
input_tokens: Some(4_012),
context_input_tokens: Some(4_012),
output_tokens: Some(9),
total_tokens: Some(4_021),
..Default::default()
}),
ModelEvent::Done(FinishReason::Stop),
]);
provider.push(text_response("new answer", 900, 5));
let assets = PromptAssets::load(
std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
.join("prompt/cursor")
.as_path(),
)
.unwrap();
let registry = TransportRegistry::new(
store.clone(),
Arc::new(provider.clone()),
PromptCompiler::new(assets),
);
let first = run(
®istry,
"first",
user_request(
"conversation",
"user-1",
"remember alpha",
&model.model_hash,
None,
),
)
.await;
let first_state = first.checkpoints.last().unwrap().clone();
let old_turns = first_state.turns.clone();
let old_roots = first_state.root_prompt_messages_json.clone();
assert!(old_roots.len() >= 3);
let compacted = run(
®istry,
"compact",
summary_request("conversation", &model.model_hash, first_state),
)
.await;
assert_eq!(compacted.summary_started, 1);
assert_eq!(compacted.summary, "Durable summary");
assert_eq!(compacted.summary_completed, 1);
assert_eq!(compacted.turn_ended, 1);
assert_eq!(compacted.token_delta, 0);
assert_eq!(compacted.checkpoints.len(), 3);
assert!(compacted
.checkpoints
.windows(2)
.all(|pair| pair[0] == pair[1]));
let compacted_state = compacted.checkpoints.last().unwrap();
assert_eq!(compacted_state.root_prompt_messages_json.len(), 2);
assert!(compacted_state.turns.starts_with(&old_turns));
assert_eq!(compacted_state.turns.len(), old_turns.len() + 1);
assert_eq!(compacted_state.self_summary_count, 1);
let summary_id = compacted_state.summary.as_ref().unwrap();
let summary = pb::ConversationSummary::decode(compacted.blobs[summary_id].as_slice()).unwrap();
assert_eq!(summary.summary, "Durable summary");
let archive_id = compacted_state.summary_archive.as_ref().unwrap();
let archive =
pb::ConversationSummaryArchive::decode(compacted.blobs[archive_id].as_slice()).unwrap();
assert_eq!(archive.summary, "Durable summary");
assert_eq!(archive.window_tail, 0);
assert_eq!(archive.summarized_messages, old_roots[1..]);
assert_eq!(
archive.summary_message,
*compacted_state.root_prompt_messages_json.last().unwrap()
);
let stored = store
.load_current_messages(&ConversationId::new("conversation"))
.await
.unwrap();
assert_eq!(stored.len(), 1);
assert_eq!(stored[0].origin, Origin::Runtime);
assert_eq!(stored[0].role, Role::User);
assert!(matches!(
&stored[0].content,
MessageContent::Parts { parts }
if matches!(parts.as_slice(), [ContentPart::Text { text }]
if text == "\nDurable summary\n")
));
let after = run(
®istry,
"after",
user_request(
"conversation",
"user-2",
"what remains?",
&model.model_hash,
Some(compacted_state.clone()),
),
)
.await;
assert!(after
.checkpoints
.last()
.unwrap()
.root_prompt_messages_json
.starts_with(&compacted_state.root_prompt_messages_json));
let requests = provider.requests();
assert_eq!(requests.len(), 3);
assert!(requests[1].prompt.tools.is_empty());
assert!(requests[1]
.prompt
.instructions
.contains("compacting conversation history"));
assert_eq!(requests[1].history.len(), 3);
assert_eq!(
requests[1].history[2].message_id, "compaction:instruction",
"an assistant-terminated history gets the summarize instruction as its user tail"
);
assert_eq!(requests[2].history.len(), 2);
let ProjectedContent::Parts(summary_parts) = &requests[2].history[0].content else {
panic!("first post-compaction message must be the summary")
};
assert!(
matches!(summary_parts.as_slice(), [ContentPart::Text { text }]
if text.contains("Durable summary"))
);
let ProjectedContent::Parts(new_user_parts) = &requests[2].history[1].content else {
panic!("second post-compaction message must be the new runtime user")
};
assert!(
matches!(new_user_parts.as_slice(), [ContentPart::Text { text }]
if text.contains("what remains?") && !text.contains("remember alpha"))
);
}
#[tokio::test]
async fn automatic_compaction_preflights_provider_input_and_records_rebuilt_tokens() {
let (_directory, store) = fixtures::temp_store().await;
let model = store
.create_model(&ModelConfigInput {
sort_order: 0,
display_name: "Auto Compact Model".into(),
group_name: None,
model_type: ModelType::OpenAi,
base_url: "https://example.com/v1/chat/completions".into(),
use_full_url: true,
api_key: "test-key".into(),
tooltip_data: "Auto Compact Model".into(),
model_id: "auto-compact-model".into(),
reasoning_effort: None,
openai_endpoint: OPENAI_CHAT_ENDPOINT.into(),
openai_extra_params_enabled: false,
openai_extra_params: serde_json::json!({}),
custom_headers_enabled: false,
custom_headers: serde_json::json!({}),
anthropic_extra_params_enabled: false,
anthropic_extra_params: serde_json::json!({}),
context_window_tokens: Some(100_000),
max_completion_tokens: None,
anthropic_max_tokens: None,
anthropic_thinking_effort: None,
thinking_budget_tokens: None,
})
.await
.unwrap();
let provider = fake_provider::FakeProvider::default();
provider.push(text_response(&"x".repeat(400_000), 150_000, 1_000));
provider.push(text_response("automatic durable summary", 120_000, 20));
provider.push(text_response("continued after compaction", 20_000, 20));
let assets = PromptAssets::load(
std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
.join("prompt/cursor")
.as_path(),
)
.unwrap();
let registry = TransportRegistry::new(
store,
Arc::new(provider.clone()),
PromptCompiler::new(assets),
);
let first = run(
®istry,
"auto-first",
user_request(
"auto-conversation",
"auto-user-1",
"start",
&model.model_hash,
None,
),
)
.await;
let first_state = first.checkpoints.last().unwrap().clone();
assert!(first_state.token_details.as_ref().unwrap().used_tokens > 100_000);
let second = run(
®istry,
"auto-second",
user_request(
"auto-conversation",
"auto-user-2",
"continue",
&model.model_hash,
Some(first_state),
),
)
.await;
assert_eq!(second.summary_started, 1);
assert_eq!(second.summary_completed, 1);
assert_eq!(
&second.interaction_events[..4],
&[
"token_delta:0",
"summary_started",
"summary_completed",
"token_delta:0",
],
"automatic compaction must publish estimated usage before summarizing and zero usage after"
);
let compacted_tokens = second
.checkpoints
.iter()
.filter_map(|state| state.token_details.as_ref())
.map(|details| details.used_tokens)
.find(|tokens| *tokens > 0 && *tokens < 100_000)
.expect("compacted checkpoint must record rebuilt context tokens");
assert!(compacted_tokens < 90_000);
let requests = provider.requests();
assert_eq!(requests.len(), 3);
assert!(!requests[0].prompt.tools.is_empty());
assert!(requests[1].prompt.tools.is_empty());
assert!(!requests[2].prompt.tools.is_empty());
assert!(requests[1]
.history
.iter()
.any(|message| match &message.content {
ProjectedContent::Assistant { text, .. } => text.len() == 400_000,
_ => false,
}));
assert!(requests[2]
.history
.iter()
.all(|message| match &message.content {
ProjectedContent::Assistant { text, .. } => text.len() != 400_000,
_ => true,
}));
}
#[tokio::test]
async fn incremental_preflight_uses_conversation_anchor_across_model_switch() {
let (_directory, store) = fixtures::temp_store().await;
let model_a = store
.create_model(&ModelConfigInput {
sort_order: 0,
display_name: "Anchor Model A".into(),
group_name: None,
model_type: ModelType::OpenAi,
base_url: "https://example.com/v1/chat/completions".into(),
use_full_url: true,
api_key: "test-key".into(),
tooltip_data: "Anchor Model A".into(),
model_id: "anchor-model-a".into(),
reasoning_effort: None,
openai_endpoint: OPENAI_CHAT_ENDPOINT.into(),
openai_extra_params_enabled: false,
openai_extra_params: serde_json::json!({}),
custom_headers_enabled: false,
custom_headers: serde_json::json!({}),
anthropic_extra_params_enabled: false,
anthropic_extra_params: serde_json::json!({}),
context_window_tokens: None,
max_completion_tokens: None,
anthropic_max_tokens: None,
anthropic_thinking_effort: None,
thinking_budget_tokens: None,
})
.await
.unwrap();
let model_b = store
.create_model(&ModelConfigInput {
sort_order: 1,
display_name: "Anchor Model B".into(),
group_name: None,
model_type: ModelType::OpenAi,
base_url: "https://example.com/v1/chat/completions".into(),
use_full_url: true,
api_key: "test-key".into(),
tooltip_data: "Anchor Model B".into(),
model_id: "anchor-model-b".into(),
reasoning_effort: None,
openai_endpoint: OPENAI_CHAT_ENDPOINT.into(),
openai_extra_params_enabled: false,
openai_extra_params: serde_json::json!({}),
custom_headers_enabled: false,
custom_headers: serde_json::json!({}),
anthropic_extra_params_enabled: false,
anthropic_extra_params: serde_json::json!({}),
context_window_tokens: Some(200_000),
max_completion_tokens: None,
anthropic_max_tokens: None,
anthropic_thinking_effort: None,
thinking_budget_tokens: None,
})
.await
.unwrap();
let provider = fake_provider::FakeProvider::default();
provider.push(text_response("old answer", 103_904, 12));
provider.push(text_response("new answer", 104_000, 12));
let assets = PromptAssets::load(
std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
.join("prompt/cursor")
.as_path(),
)
.unwrap();
let registry = TransportRegistry::new(
store,
Arc::new(provider.clone()),
PromptCompiler::new(assets),
);
let first = run(
®istry,
"anchor-first",
user_request(
"anchor-conversation",
"anchor-user-1",
&"x".repeat(400_000),
&model_a.model_hash,
None,
),
)
.await;
let second = run(
®istry,
"anchor-second",
user_request(
"anchor-conversation",
"anchor-user-2",
"short follow-up",
&model_b.model_hash,
first.checkpoints.last().cloned(),
),
)
.await;
assert_eq!(second.summary_started, 0);
assert_eq!(second.summary_completed, 0);
assert_eq!(provider.requests().len(), 2);
}
#[tokio::test]
async fn irreducibly_oversized_current_input_fails_before_provider_dispatch() {
let (_directory, store) = fixtures::temp_store().await;
let model = store
.create_model(&ModelConfigInput {
sort_order: 0,
display_name: "Overflow Model".into(),
group_name: None,
model_type: ModelType::OpenAi,
base_url: "https://example.com/v1/chat/completions".into(),
use_full_url: true,
api_key: "test-key".into(),
tooltip_data: "Overflow Model".into(),
model_id: "overflow-model".into(),
reasoning_effort: None,
openai_endpoint: OPENAI_CHAT_ENDPOINT.into(),
openai_extra_params_enabled: false,
openai_extra_params: serde_json::json!({}),
custom_headers_enabled: false,
custom_headers: serde_json::json!({}),
anthropic_extra_params_enabled: false,
anthropic_extra_params: serde_json::json!({}),
context_window_tokens: Some(100_000),
max_completion_tokens: None,
anthropic_max_tokens: None,
anthropic_thinking_effort: None,
thinking_budget_tokens: None,
})
.await
.unwrap();
let provider = fake_provider::FakeProvider::default();
let assets = PromptAssets::load(
std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
.join("prompt/cursor")
.as_path(),
)
.unwrap();
let registry = TransportRegistry::new(
store,
Arc::new(provider.clone()),
PromptCompiler::new(assets),
);
let output = run(
®istry,
"overflow-request",
user_request(
"overflow-conversation",
"overflow-user",
&"x".repeat(400_000),
&model.model_hash,
None,
),
)
.await;
assert!(provider.requests().is_empty());
assert_eq!(output.summary_started, 0);
assert_eq!(output.summary_completed, 0);
}
fn windowed_model(model_id: &str, context_window_tokens: Option) -> ModelConfigInput {
ModelConfigInput {
sort_order: 0,
display_name: model_id.into(),
group_name: None,
model_type: ModelType::OpenAi,
base_url: "https://example.com/v1/chat/completions".into(),
use_full_url: true,
api_key: "test-key".into(),
tooltip_data: model_id.into(),
model_id: model_id.into(),
reasoning_effort: None,
openai_endpoint: OPENAI_CHAT_ENDPOINT.into(),
openai_extra_params_enabled: false,
openai_extra_params: serde_json::json!({}),
custom_headers_enabled: false,
custom_headers: serde_json::json!({}),
anthropic_extra_params_enabled: false,
anthropic_extra_params: serde_json::json!({}),
context_window_tokens,
max_completion_tokens: None,
anthropic_max_tokens: None,
anthropic_thinking_effort: None,
thinking_budget_tokens: None,
}
}
#[tokio::test]
async fn provider_overflow_refusal_compacts_and_retries_once() {
// The estimate cleared the compaction check, but the provider counted
// more and refused. The refusal is the trigger the estimate missed.
let (_directory, store) = fixtures::temp_store().await;
let model = store
.create_model(&windowed_model("refusal-model", Some(1_000_000)))
.await
.unwrap();
let provider = fake_provider::FakeProvider::default();
provider.push(text_response("first answer", 4_000, 12));
provider.push_error(cursor_server::Error::Provider(
"Anthropic 400 Bad Request: {\"type\":\"error\",\"error\":{\"type\":\
\"invalid_request_error\",\"message\":\"prompt is too long: 1002148 tokens > \
1000000 maximum\"}}"
.into(),
));
provider.push(text_response("durable summary", 3_000, 20));
provider.push(text_response("answer after compaction", 500, 20));
let assets = PromptAssets::load(
std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
.join("prompt/cursor")
.as_path(),
)
.unwrap();
let registry = TransportRegistry::new(
store,
Arc::new(provider.clone()),
PromptCompiler::new(assets),
);
let first = run(
®istry,
"refusal-first",
user_request(
"refusal-conversation",
"refusal-user-1",
"start",
&model.model_hash,
None,
),
)
.await;
let second = run(
®istry,
"refusal-second",
user_request(
"refusal-conversation",
"refusal-user-2",
"continue",
&model.model_hash,
first.checkpoints.last().cloned(),
),
)
.await;
assert_eq!(second.summary_started, 1);
assert_eq!(second.summary_completed, 1);
assert_eq!(second.turn_ended, 1);
let requests = provider.requests();
assert_eq!(
requests.len(),
4,
"refused call, summary call, retried call"
);
assert!(requests[2].prompt.tools.is_empty());
assert_eq!(
requests[2].history.last().unwrap().role,
Role::User,
"the summarizer history must end with a user message"
);
assert!(!requests[3].prompt.tools.is_empty());
assert!(requests[3]
.history
.iter()
.any(|message| match &message.content {
ProjectedContent::Parts(parts) =>
matches!(parts.as_slice(), [ContentPart::Text { text }]
if text.contains("durable summary")),
_ => false,
}));
}
#[tokio::test]
async fn assistant_terminated_history_is_sent_with_a_user_tail() {
// Cursor can resume a conversation whose committed history already ends
// with the assistant. Anthropic refuses that as a prefill, so the run
// appends a provider-visible continuation without persisting it.
let (_directory, store) = fixtures::temp_store().await;
let model = store
.create_model(&windowed_model("tail-model", None))
.await
.unwrap();
let provider = fake_provider::FakeProvider::default();
provider.push(text_response("first answer", 400, 12));
provider.push(text_response("resumed answer", 450, 12));
let assets = PromptAssets::load(
std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
.join("prompt/cursor")
.as_path(),
)
.unwrap();
let registry = TransportRegistry::new(
store.clone(),
Arc::new(provider.clone()),
PromptCompiler::new(assets),
);
let first = run(
®istry,
"tail-first",
user_request(
"tail-conversation",
"tail-user-1",
"start",
&model.model_hash,
None,
),
)
.await;
let resumed = run(
®istry,
"tail-resume",
request(
"tail-conversation",
&model.model_hash,
first.checkpoints.last().cloned(),
pb::conversation_action::Action::ResumeAction(pb::ResumeAction::default()),
),
)
.await;
assert_eq!(resumed.turn_ended, 1);
let requests = provider.requests();
assert_eq!(requests.len(), 2);
let tail = requests[1].history.last().unwrap();
assert_eq!(tail.role, Role::User);
assert_eq!(tail.message_id, "runtime:continue");
assert_eq!(
requests[1].history[..requests[1].history.len() - 1]
.iter()
.map(|message| message.message_id.as_str())
.collect::>()
.len(),
requests[0].history.len() + 1,
"committed history plus the first answer, then the transient tail"
);
let stored = store
.load_current_messages(&ConversationId::new("tail-conversation"))
.await
.unwrap();
assert!(
stored
.iter()
.all(|message| message.message_id != "runtime:continue"),
"the continuation tail is provider-visible only and never persisted"
);
}
#[derive(Default)]
struct Output {
checkpoints: Vec,
blobs: HashMap, Vec>,
summary: String,
summary_started: usize,
summary_completed: usize,
turn_ended: usize,
token_delta: usize,
interaction_events: Vec,
}
async fn run(
registry: &TransportRegistry,
request_id: &str,
request: pb::AgentClientMessage,
) -> Output {
let handle = registry.get_or_create(request_id).await.unwrap();
let mut receiver = handle.subscribe();
handle
.command(TransportCommand::Append {
seqno: 0,
message: Box::new(request),
})
.await
.unwrap();
let mut append_seqno = 1;
let mut output = Output::default();
loop {
let frame = tokio::time::timeout(Duration::from_secs(5), receiver.recv())
.await
.unwrap()
.unwrap();
let (flags, payload) = connect::decode_frames(&frame).unwrap().pop().unwrap();
if flags & connect::END_STREAM_FLAG != 0 {
return output;
}
let server = pb::AgentServerMessage::decode(payload).unwrap();
match server.message {
Some(pb::agent_server_message::Message::KvServerMessage(kv)) => {
if let Some(pb::kv_server_message::Message::SetBlobArgs(set)) = kv.message {
output.blobs.insert(set.blob_id, set.blob_data);
}
handle
.command(TransportCommand::Append {
seqno: append_seqno,
message: Box::new(kv_ack(kv.id)),
})
.await
.unwrap();
append_seqno += 1;
}
Some(pb::agent_server_message::Message::ConversationCheckpointUpdate(state)) => {
output.checkpoints.push(state)
}
Some(pb::agent_server_message::Message::InteractionUpdate(update)) => {
match update.message {
Some(pb::interaction_update::Message::SummaryStarted(_)) => {
output.summary_started += 1;
output.interaction_events.push("summary_started".into());
}
Some(pb::interaction_update::Message::Summary(delta)) => {
output.summary.push_str(&delta.summary)
}
Some(pb::interaction_update::Message::SummaryCompleted(_)) => {
output.summary_completed += 1;
output.interaction_events.push("summary_completed".into());
}
Some(pb::interaction_update::Message::TurnEnded(_)) => output.turn_ended += 1,
Some(pb::interaction_update::Message::TokenDelta(delta)) => {
output.token_delta += 1;
output
.interaction_events
.push(format!("token_delta:{}", delta.tokens));
}
_ => {}
}
}
_ => {}
}
}
}
fn text_response(text: &str, input: u64, output: u64) -> Vec {
vec![
ModelEvent::Start {
model_call_id: format!("call-{text}"),
},
ModelEvent::TextStart,
ModelEvent::TextDelta(text.into()),
ModelEvent::TextEnd,
ModelEvent::Usage(Usage {
input_tokens: Some(input),
context_input_tokens: Some(input),
output_tokens: Some(output),
total_tokens: Some(input + output),
..Default::default()
}),
ModelEvent::Done(FinishReason::Stop),
]
}
fn user_request(
conversation_id: &str,
message_id: &str,
text: &str,
model_id: &str,
state: Option,
) -> pb::AgentClientMessage {
let user = pb::UserMessage {
text: text.into(),
message_id: message_id.into(),
mode: pb::AgentMode::Agent as i32,
..Default::default()
};
request(
conversation_id,
model_id,
state,
pb::conversation_action::Action::UserMessageAction(pb::UserMessageAction {
user_message: Some(user),
request_context: Some(pb::RequestContext::default()),
..Default::default()
}),
)
}
fn summary_request(
conversation_id: &str,
model_id: &str,
state: pb::ConversationStateStructure,
) -> pb::AgentClientMessage {
let user = pb::UserMessage {
text: "/summarize".into(),
message_id: "summary-command".into(),
mode: pb::AgentMode::Agent as i32,
..Default::default()
};
request(
conversation_id,
model_id,
Some(state),
pb::conversation_action::Action::UserMessageAction(pb::UserMessageAction {
user_message: Some(user),
request_context: Some(pb::RequestContext::default()),
..Default::default()
}),
)
}
fn request(
conversation_id: &str,
model_id: &str,
state: Option,
action: pb::conversation_action::Action,
) -> pb::AgentClientMessage {
pb::AgentClientMessage {
message: Some(pb::agent_client_message::Message::RunRequest(
pb::AgentRunRequest {
requested_model: Some(pb::RequestedModel {
model_id: model_id.into(),
..Default::default()
}),
action: Some(pb::ConversationAction {
action: Some(action),
..Default::default()
}),
conversation_id: Some(conversation_id.into()),
conversation_state: state,
run_id: Some("reusable-wire-run-id".into()),
..Default::default()
},
)),
}
}
fn kv_ack(id: u32) -> pb::AgentClientMessage {
pb::AgentClientMessage {
message: Some(pb::agent_client_message::Message::KvClientMessage(
pb::KvClientMessage {
id,
message: Some(pb::kv_client_message::Message::SetBlobResult(
pb::SetBlobResult { error: None },
)),
},
)),
}
}