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Lock tool sessions to their model

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This commit is contained in:
Georg Bauer
2026-09-01 22:37:57 +02:00
parent d40e86e5ef
commit 35f306bf2a
14 changed files with 299 additions and 7 deletions
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7
docs/USER_GUIDE.md
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@@ -196,6 +196,13 @@ stored per model; the custom system prompt is shared across profiles. Other
sections control A2UI, permission defaults, endpoint settings, Git diff display,
Dev Brain, extensions, checkpoint storage, and diagnostics.
A session remains model-independent until its first tool call. That call locks
the session to its model so persisted tool syntax is never mixed. Continuing a
locked session while another model is active asks before switching back. Legacy
sessions recover the exact model from their checkpoint when available; a legacy
tool session whose exact model can no longer be identified remains viewable but
cannot be continued.
### Main views, sidebar, and branches
**Chat** shows the conversation, **A2UI** shows interactive surfaces, **Git**

1
migrations/20260901223000_add_session_model/down.sql Normal file
View File

@@ -0,0 +1 @@
ALTER TABLE sessions DROP COLUMN model;

7
migrations/20260901223000_add_session_model/up.sql Normal file
View File

@@ -0,0 +1,7 @@
ALTER TABLE sessions ADD COLUMN model TEXT
CHECK (model IS NULL OR model IN (
'deepseek-v4-flash-0731',
'deepseek-v4-pro',
'glm-5.2',
'glm-5.3-flash'
));

6
src/agent.rs
View File

@@ -3627,6 +3627,12 @@ pub(crate) fn parse_tool_calls(
.map(|calls| (content, calls))
}
pub(crate) fn tool_protocol_model(text: &str) -> Option<ModelChoice> {
[ModelChoice::DeepSeekV4Flash0731, ModelChoice::Glm52]
.into_iter()
.find(|model| parse_tool_calls(*model, text).is_ok_and(|(_, calls)| !calls.is_empty()))
}
pub(crate) fn system_prompt(model: ModelChoice, extra: &str, dev_brain: bool) -> String {
system_prompt_with_tools(model, extra, dev_brain, false)
}

115
src/app.rs
View File

@@ -105,6 +105,8 @@ pub(crate) struct App {
session_menu: Option<i32>,
/// Session waiting for explicit confirmation before deletion.
pending_session_delete: Option<i32>,
/// Locked session model waiting to replace the current global selection.
pending_session_model_switch: Option<ModelChoice>,
/// Session being renamed, with the in-progress title.
session_rename: Option<(i32, String)>,
/// Projects whose archived sessions are expanded in the sidebar.
@@ -500,6 +502,8 @@ pub(crate) enum Message {
AllowToolOnce,
DenyTool,
SubmitPrompt,
ConfirmSessionModelSwitch,
CancelSessionModelSwitch,
StopGeneration,
GenerationTick,
ChatScrolled(scrollable::Viewport),
@@ -645,6 +649,7 @@ impl App {
background_chats: HashMap::new(),
session_menu: None,
pending_session_delete: None,
pending_session_model_switch: None,
session_rename: None,
expanded_archives: HashSet::new(),
sidebar_drag: false,
@@ -810,6 +815,7 @@ impl App {
background_chats: HashMap::new(),
session_menu: None,
pending_session_delete: None,
pending_session_model_switch: None,
session_rename: None,
expanded_archives: HashSet::new(),
sidebar_drag: false,
@@ -1134,7 +1140,7 @@ impl App {
let content = export_chat(
format,
&title,
self.config.model,
self.chat_parser_model(),
&self.conversation,
&surfaces,
&images,
@@ -1241,6 +1247,8 @@ impl App {
Message::DismissPanel => {
if self.quit_confirmation {
self.quit_confirmation = false;
} else if self.pending_session_model_switch.is_some() {
self.pending_session_model_switch = None;
} else if self.git_diff.is_some() {
self.git_diff = None;
} else if self.git_commit_all_confirmation {
@@ -1559,10 +1567,57 @@ impl App {
}
}
Message::SubmitPrompt => {
if !self.generating && self.selected_session.is_some() {
match required_session_model_switch(
self.config.model,
self.selected_session_model(),
self.chat_tool_protocol_model(),
) {
Ok(Some(model)) => {
self.pending_session_model_switch = Some(model);
return Task::none();
}
Err(protocol) => {
self.error = Some(format!(
"This legacy session contains {} tool calls, but its exact model was not recorded and no compatible checkpoint remains. Start a new session to continue safely.",
if protocol.is_glm() { "GLM" } else { "DeepSeek" }
));
return Task::none();
}
Ok(None) => {}
}
}
self.chat_follow_tail = true;
self.start_generation();
return scroll_chat_to_end();
}
Message::ConfirmSessionModelSwitch => {
let Some(model) = self.pending_session_model_switch.take() else {
return Task::none();
};
let mut config = self.config.clone();
config.model = model;
if let Err(error) = config.save(&config_path()) {
self.error = Some(error);
return Task::none();
}
self.config = config;
self.preference_draft = PreferenceDraft::from_saved(&self.config);
self.context_limit = self.config.active_generation().context_tokens.max(0) as u32;
if model != ModelChoice::Glm53Flash {
self.pending_vision_image = None;
}
#[cfg(target_os = "macos")]
{
self.agent_tools = None;
preferences::update_runtime_config(&self.runtime_config, &self.config);
}
self.error = None;
self.chat_follow_tail = true;
self.start_generation();
return scroll_chat_to_end();
}
Message::CancelSessionModelSwitch => self.pending_session_model_switch = None,
Message::StopGeneration => {
self.stop_requested = true;
self.activity = Some("Stopping…".into());
@@ -1938,6 +1993,7 @@ impl App {
if self.selected_session == Some(session_id) {
return Task::none();
}
self.pending_session_model_switch = None;
#[cfg(target_os = "macos")]
{
self.leave_current_chat();
@@ -1964,6 +2020,7 @@ impl App {
session.context_limit,
session.last_tokens_per_second,
session.permission_mode(),
session.model(),
)
});
let Some(database) = &mut self.database else {
@@ -1980,6 +2037,27 @@ impl App {
self.error = Some(format!("Could not update the session: {error}"));
return Task::none();
}
let stored_model = saved_context
.as_ref()
.and_then(|(_, _, _, _, model)| *model);
let protocol_model = messages.iter().find_map(|message| {
crate::agent::tool_protocol_model(&message.content)
});
if stored_model.is_none()
&& let (Some(protocol_model), Some(checkpoint_model)) = (
protocol_model,
crate::engine::checkpoint_model(&session_checkpoint_path(
session_id,
)),
)
&& protocol_model.is_glm() == checkpoint_model.is_glm()
&& let Err(error) =
database.set_session_model(session_id, checkpoint_model)
{
self.error =
Some(format!("Could not restore the session model: {error}"));
return Task::none();
}
self.conversation = messages.into_iter().map(ChatMessage::from).collect();
self.chat_follow_tail = true;
generation::promote_legacy_turn_summaries(&mut self.conversation);
@@ -2005,8 +2083,8 @@ impl App {
self.selected_session = Some(session_id);
self.system_prompt_seen_at = 0;
self.queued_inputs.clear();
let (used, limit, tokens_per_second, permission_mode) =
saved_context.unwrap_or((0, 0, None, PermissionMode::default()));
let (used, limit, tokens_per_second, permission_mode, _) =
saved_context.unwrap_or((0, 0, None, PermissionMode::default(), None));
self.context_used = used.max(0) as u32;
self.context_limit = if limit > 0 {
limit as u32
@@ -3154,6 +3232,18 @@ fn session_checkpoint_path(session_id: i32) -> PathBuf {
kv_cache_path().join(format!("{session_id}.bin"))
}
fn required_session_model_switch(
current: ModelChoice,
locked: Option<ModelChoice>,
legacy_protocol: Option<ModelChoice>,
) -> Result<Option<ModelChoice>, ModelChoice> {
match locked {
Some(model) if model != current => Ok(Some(model)),
Some(_) => Ok(None),
None => legacy_protocol.map_or(Ok(None), Err),
}
}
fn discard_session_checkpoint_files(directory: &Path, session_id: i32) -> Result<bool, String> {
let mut removed = false;
for extension in ["bin", "tmp", "compacting"] {
@@ -3204,6 +3294,25 @@ pub(crate) fn app_icon() -> window::Icon {
mod tests {
use super::*;
#[test]
fn tool_calls_lock_continuation_to_the_session_model() {
let flash = ModelChoice::DeepSeekV4Flash0731;
let glm = ModelChoice::Glm53Flash;
assert_eq!(
required_session_model_switch(flash, Some(flash), None),
Ok(None)
);
assert_eq!(
required_session_model_switch(glm, Some(flash), None),
Ok(Some(flash))
);
assert_eq!(
required_session_model_switch(glm, None, Some(flash)),
Err(flash)
);
assert_eq!(required_session_model_switch(glm, None, None), Ok(None));
}
#[test]
fn preferences_shortcut_and_dspark_support_are_explicit() {
let message = shortcut(

5
src/app/generation.rs
View File

@@ -1584,6 +1584,11 @@ impl App {
let session_id = self
.selected_session
.ok_or_else(|| "The active session is unavailable.".to_owned())?;
self.database
.as_mut()
.ok_or_else(|| "The project database is unavailable.".to_owned())?
.set_session_model(session_id, self.config.model)?;
self.reload_projects();
if self.agent_tools.as_ref().map(|(id, _)| *id) != Some(session_id) {
let project_id = self
.selected_project

22
src/app/projects.rs
View File

@@ -1,6 +1,27 @@
use super::*;
impl App {
pub(super) fn selected_session_model(&self) -> Option<ModelChoice> {
let session_id = self.selected_session?;
self.projects
.iter()
.flat_map(|project| &project.sessions)
.find(|session| session.id == session_id)
.and_then(|session| session.model())
}
pub(super) fn chat_tool_protocol_model(&self) -> Option<ModelChoice> {
self.conversation
.iter()
.find_map(|message| crate::agent::tool_protocol_model(&message.content))
}
pub(super) fn chat_parser_model(&self) -> ModelChoice {
self.selected_session_model()
.or_else(|| self.chat_tool_protocol_model())
.unwrap_or(self.config.model)
}
pub(super) fn clear_a2ui(&mut self) {
self.a2ui.clear();
self.a2ui_history.clear();
@@ -171,6 +192,7 @@ impl App {
self.drafts.entry(project_id).or_insert(title);
self.remember_project(project_id);
self.selected_session = None;
self.pending_session_model_switch = None;
self.permission_mode = self.config.default_permission_mode;
self.conversation.clear();
self.chat_follow_tail = true;

38
src/app/view.rs
View File

@@ -110,6 +110,7 @@ impl App {
/// tree, so the layers below have to stay out of the dialog's field order.
pub(super) fn modal_open(&self) -> bool {
self.quit_confirmation
|| self.pending_session_model_switch.is_some()
|| self.git_diff.is_some()
|| self.git_commit_all_confirmation
|| self.pending_project_path.is_some()
@@ -174,6 +175,8 @@ impl App {
#[cfg(target_os = "macos")]
if self.quit_confirmation {
layers.push(self.quit_confirmation_panel());
} else if let Some(model) = self.pending_session_model_switch {
layers.push(self.session_model_switch_panel(model));
} else if let Some((prompt, _)) = &self.pending_tool_approval {
layers.push(self.tool_approval_panel(prompt));
} else if let Some(path) = &self.pending_project_path {
@@ -196,6 +199,8 @@ impl App {
#[cfg(not(target_os = "macos"))]
if self.quit_confirmation {
layers.push(self.quit_confirmation_panel());
} else if let Some(model) = self.pending_session_model_switch {
layers.push(self.session_model_switch_panel(model));
} else if let Some(path) = &self.pending_project_path {
layers.push(self.project_dialog(path));
} else if let Some((_, title)) = &self.session_rename {
@@ -252,6 +257,39 @@ impl App {
)
}
fn session_model_switch_panel(&self, model: ModelChoice) -> Element<'_, Message> {
let title = self.active_chat_title().unwrap_or("This session");
let dialog = container(
column![
text("Switch model to continue?").size(22),
text(format!(
"“{title}” is locked to {model} because it contains that model's tool calls. Continuing will switch the active model from {} to {model}.",
self.config.model
))
.size(13),
row![
Space::new().width(Length::Fill),
action_button("Cancel").on_press(Message::CancelSessionModelSwitch),
action_button("Switch and continue")
.on_press(Message::ConfirmSessionModelSwitch),
]
.spacing(8),
]
.spacing(12),
)
.padding(22)
.width(520)
.style(overview_style);
opaque(
container(dialog)
.center_x(Length::Fill)
.center_y(Length::Fill)
.style(|_| {
container::Style::default().background(Color::from_rgba8(0, 0, 0, 0.68))
}),
)
}
#[cfg(target_os = "macos")]
fn tool_approval_panel<'a>(
&'a self,

4
src/app/view/chat.rs
View File

@@ -80,7 +80,7 @@ impl App {
if message.tool
&& index > 0
&& !crate::agent::stored_tool_cards(
self.config.model,
self.chat_parser_model(),
&self.conversation[index - 1].content,
None,
&self.conversation[index - 1].tool_approval_reasons,
@@ -191,7 +191,7 @@ impl App {
}
} else {
crate::agent::stored_tool_cards(
self.config.model,
self.chat_parser_model(),
&message.content,
stored_result,
&message.tool_approval_reasons,

2
src/app/view/stats.rs
View File

@@ -5,7 +5,7 @@ use iced::widget::column;
impl App {
pub(super) fn stats_dashboard(&self) -> Element<'_, Message> {
let stats = &self.metrics_snapshot;
let session = SessionStats::from_messages(&self.conversation, self.config.model);
let session = SessionStats::from_messages(&self.conversation, self.chat_parser_model());
let context_fraction = if stats.context_limit == 0 {
0.0
} else {

55
src/database.rs
View File

@@ -45,6 +45,8 @@ pub struct Session {
last_used: i64,
/// Raw column value; read it through [`Session::permission_mode`].
permission_mode: String,
/// Locked after the first tool call; read it through [`Session::model`].
model: Option<String>,
}
impl Session {
@@ -56,6 +58,12 @@ impl Session {
PermissionMode::from_id(&self.permission_mode).unwrap_or_default()
}
pub(crate) fn model(&self) -> Option<crate::model::ModelChoice> {
self.model
.as_deref()
.and_then(crate::model::ModelChoice::from_id)
}
#[cfg(test)]
pub fn fixture(id: i32, project_id: i32, title: &str, state: SessionState) -> Self {
Self {
@@ -69,6 +77,7 @@ impl Session {
compacted_summary: None,
last_used: 0,
permission_mode: PermissionMode::default().as_id().to_owned(),
model: None,
}
}
}
@@ -411,6 +420,25 @@ impl Database {
.map_err(|error| error.to_string())
}
pub(crate) fn set_session_model(
&mut self,
session_id: i32,
model: crate::model::ModelChoice,
) -> Result<(), String> {
let updated = diesel::update(
sessions::table
.find(session_id)
.filter(sessions::model.is_null().or(sessions::model.eq(model.id()))),
)
.set(sessions::model.eq(model.id()))
.execute(&mut self.connection)
.map_err(|error| error.to_string())?;
if updated == 0 {
return Err("The session is locked to a different model.".into());
}
Ok(())
}
pub fn touch_session(&mut self, session_id: i32) -> Result<(), String> {
touch_session(&mut self.connection, session_id).map_err(|error| error.to_string())
}
@@ -820,13 +848,29 @@ mod tests {
assert_eq!(loaded[0].sessions[0].title, "Second session");
assert_eq!(loaded[0].sessions[0].state(), SessionState::Normal);
assert_eq!(loaded[0].sessions[0].permission_mode(), PermissionMode::Ai);
assert_eq!(loaded[0].sessions[0].model(), None);
database
.set_session_permission_mode(second.id, PermissionMode::Heuristic)
.unwrap();
database
.set_session_model(second.id, crate::model::ModelChoice::DeepSeekV4Flash0731)
.unwrap();
database
.set_session_model(second.id, crate::model::ModelChoice::DeepSeekV4Flash0731)
.unwrap();
assert!(
database
.set_session_model(second.id, crate::model::ModelChoice::Glm53Flash)
.is_err()
);
assert_eq!(
database.load_projects().unwrap()[0].sessions[0].permission_mode(),
PermissionMode::Heuristic
);
assert_eq!(
database.load_projects().unwrap()[0].sessions[0].model(),
Some(crate::model::ModelChoice::DeepSeekV4Flash0731)
);
let ordinary = loaded[0].sessions[0].id;
let pinned = database
@@ -1288,6 +1332,9 @@ mod tests {
"Tool result 1 (present_svg):\nSVG presented inline: A dark rectangle\n",
)
.unwrap();
database
.set_session_model(session.id, crate::model::ModelChoice::DeepSeekV4Flash0731)
.unwrap();
database
.record_compaction(session.id, "Later context summary.", None, None, 100, 1_000)
.unwrap();
@@ -1307,8 +1354,14 @@ mod tests {
.iter()
.position(|message| message.id == assistant.id)
.unwrap();
let session_model = reopened.load_projects().unwrap()[0]
.sessions
.iter()
.find(|stored| stored.id == session.id)
.and_then(Session::model)
.unwrap();
let cards = crate::agent::stored_tool_cards(
crate::model::ModelChoice::DeepSeekV4Flash0731,
session_model,
&messages[assistant_index].content,
Some(&messages[assistant_index + 1].content),
&[],

39
src/engine.rs
View File

@@ -22,6 +22,8 @@ use kvstore::{KvStore, StoreReason};
use sha2::{Digest, Sha256};
#[cfg(target_os = "macos")]
use std::collections::HashMap;
use std::fs::File;
use std::io::{Read, Seek, SeekFrom};
use std::path::Path;
#[cfg(target_os = "macos")]
use std::path::PathBuf;
@@ -43,6 +45,24 @@ const VISION_START_TOKEN: i32 = 154_830;
const VISION_END_TOKEN: i32 = 154_831;
type VisionOverlays = Vec<(u32, metal::VisionEmbedding)>;
pub(crate) fn checkpoint_model(path: &Path) -> Option<ModelChoice> {
let mut file = File::open(path).ok()?;
let mut magic = [0; 8];
file.read_exact(&mut magic).ok()?;
let model_size_offset = match &magic {
b"DS4RKV01" => 40,
b"DS4GLM01" => 44,
_ => return None,
};
file.seek(SeekFrom::Start(model_size_offset)).ok()?;
let mut bytes = [0; 8];
file.read_exact(&mut bytes).ok()?;
let size = u64::from_le_bytes(bytes);
crate::model::MODEL_CHOICES
.into_iter()
.find(|model| model.main_artifact_size() == size)
}
pub(crate) fn vision_data_marker(uri: &str) -> String {
format!("{VISION_DATA_START}{uri}{VISION_DATA_END}")
}
@@ -1917,6 +1937,25 @@ impl Rng {
mod sampling_tests {
use super::*;
#[test]
fn checkpoint_headers_identify_the_exact_model() {
let path =
std::env::temp_dir().join(format!("ds4-checkpoint-model-{}", std::process::id()));
for (magic, offset, model) in [
(b"DS4RKV01".as_slice(), 40, ModelChoice::DeepSeekV4Flash0731),
(b"DS4RKV01".as_slice(), 40, ModelChoice::DeepSeekV4Pro),
(b"DS4GLM01".as_slice(), 44, ModelChoice::Glm52),
(b"DS4GLM01".as_slice(), 44, ModelChoice::Glm53Flash),
] {
let mut bytes = magic.to_vec();
bytes.resize(offset, 0);
bytes.extend_from_slice(&model.main_artifact_size().to_le_bytes());
std::fs::write(&path, bytes).unwrap();
assert_eq!(checkpoint_model(&path), Some(model));
}
std::fs::remove_file(path).unwrap();
}
#[test]
fn zero_temperature_is_greedy() {
let mut rng = Rng::new(1);

4
src/model.rs
View File

@@ -122,6 +122,10 @@ impl ModelChoice {
self.is_glm()
}
pub(crate) fn main_artifact_size(self) -> u64 {
self.main_artifact().size
}
fn main_artifact(self) -> &'static Artifact {
match self {
Self::DeepSeekV4Flash0731 => &FLASH_0731,

1
src/schema.rs
View File

@@ -51,6 +51,7 @@ diesel::table! {
compacted_summary -> Nullable<Text>,
last_used -> BigInt,
permission_mode -> Text,
model -> Nullable<Text>,
}
}