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//! Advisor mode as a runtime state transition.
//!
//! Advisor mode changes the advertised tool list, which the SDK cannot swap on
//! a live runtime. Turning it on or off therefore rebuilds the runtime and
//! rebinds the session so the change lands on the next turn. The session ID and
//! history survive it.
//!
//! The system prompt stays fixed for prompt-cache stability. The model learns
//! about the tool list change from an appended context notice (with the tool
//! schema when enabling) rather than a rewritten system prompt.
use std::sync::Arc;
use rho_sdk::{SessionOptions, SystemPrompt};
use crate::config::InternalAgentModelConfig;
use super::super::runtime_builder::{build_runtime, RuntimeBuildOptions};
use super::InteractiveRuntime;
#[cfg(test)]
thread_local! {
/// When set, the next advisor notice appends model-visible history, then
/// fails snapshot persistence so rollback must cover the partial commit.
static FAIL_NEXT_ADVISOR_NOTICE_SNAPSHOT_SAVE: std::cell::Cell<bool> =
const { std::cell::Cell::new(false) };
}
#[cfg(test)]
pub(crate) fn fail_next_advisor_switch_notice_for_tests() {
FAIL_NEXT_ADVISOR_NOTICE_SNAPSHOT_SAVE.with(|flag| flag.set(true));
}
#[cfg(test)]
pub(super) fn take_fail_next_advisor_notice_snapshot_save_for_tests() -> bool {
FAIL_NEXT_ADVISOR_NOTICE_SNAPSHOT_SAVE.with(|flag| flag.replace(false))
}
impl InteractiveRuntime {
/// Fixed system prompt for this session.
///
/// Mid-session tool list changes keep this value stable and tell the model
/// through appended context instead.
pub(super) fn active_system_prompt(&self) -> SystemPrompt {
self.system_prompt.clone()
}
/// Applies an advisor mode or advisor model change to the next turn.
///
/// `model` is the advisor model to use, or `None` when advisor mode is off
/// or has no model yet; those are the same thing to the executor. The live
/// tool reads the new model at once. Registering or removing the `advisor`
/// tool rebuilds the runtime without rewriting the system prompt, then
/// appends a context notice. A model-only change while advisor stays on
/// appends a switch notice without rebuilding. Returns display text for a
/// transcript notice when one was appended.
pub(crate) async fn set_advisor(
&mut self,
model: Option<InternalAgentModelConfig>,
) -> anyhow::Result<Option<String>> {
let Some(store) = self.tools.advisor().cloned() else {
return Ok(None);
};
let registered = model.is_some();
if registered == self.tools.advisor_registered() {
// The tool list is unchanged, so nothing rebuilds and nothing else
// would say the reviewer behind `advisor` is a different model.
//
// Compare what the notice reports, not the whole selection: a
// reasoning-only change would otherwise announce a switch to the
// model the advisor already used.
let previous_model = store.model();
let previous_identity = previous_model
.as_ref()
.map(crate::model_identity::PromptModel::from_internal_agent);
let notice = model
.as_ref()
.map(crate::model_identity::PromptModel::from_internal_agent)
.filter(|identity| previous_identity.as_ref() != Some(identity))
.map(|identity| {
crate::prompt::model_switch_context(
crate::prompt::ModelSwitchKind::Advisor,
&identity,
)
});
store.set_model(model);
let Some((context, display)) = notice else {
return Ok(None);
};
if let Err(error) = self.append_user_context_with_display(context, display.clone()) {
// Same rule as the transition below: the store must not hold a
// reviewer the executor was never told about.
store.set_model(previous_model);
return Err(error);
}
return Ok(Some(display));
}
if self.runs.is_active() {
anyhow::bail!("advisor mode cannot change while a run is active");
}
// The model lands only after the rebuild succeeds, so a failed
// transition leaves both the tool list and the store untouched.
let previous_registered = self.tools.advisor_registered();
let previous_model = store.model();
let history_before = self.sessions.history();
self.tools.set_advisor_registered(registered);
match self.rebind_current_session().await {
Ok(()) => {
store.set_model(model);
// After `set_model`, so the enable notice names the model the
// tool will actually consult.
match self.append_advisor_switch_notice(registered) {
Ok(display) => {
self.remember_tool_list();
Ok(Some(display))
}
Err(error) => {
// Mirror edit-tool: a notice failure must not leave the
// session advertising a tool list the model was never
// told about. Also restore model-visible history when a
// partial append-before-save left a notice in place.
store.set_model(previous_model);
self.tools.set_advisor_registered(previous_registered);
if self.sessions.history() != history_before {
let _ = self.sessions.session().replace_history(history_before);
}
let _ = self.rebind_current_session().await;
Err(error)
}
}
}
Err(error) => {
self.tools.set_advisor_registered(previous_registered);
Err(error)
}
}
}
fn append_advisor_switch_notice(&mut self, enabled: bool) -> anyhow::Result<String> {
let (model, display) = if enabled {
let spec = self
.tools
.specs()
.into_iter()
.find(|spec| spec.name == crate::tools::advisor::TOOL_NAME)
.ok_or_else(|| {
anyhow::anyhow!("advisor tool is missing after it was registered")
})?;
let reviewer = self
.tools
.advisor()
.and_then(crate::tools::advisor::AdvisorSessionStore::model)
.ok_or_else(|| {
anyhow::anyhow!("advisor tool is registered without an advisor model")
})?;
crate::prompt::advisor_enabled_context(
&spec,
&crate::model_identity::PromptModel::from_internal_agent(&reviewer),
)
} else {
crate::prompt::advisor_disabled_context()
};
self.append_user_context_with_display(model, display.clone())?;
Ok(display)
}
/// Rebuilds the SDK runtime around the current tools and prompt, then
/// rebinds the live session onto it. The live runtime is replaced only
/// after the replacement is ready, so a failure leaves the session intact.
///
/// Callers that change the advertised tool list should keep the system
/// prompt fixed for prompt-cache stability and tell the model about the
/// change with an appended context message instead.
pub(super) async fn rebind_current_session(&mut self) -> anyhow::Result<()> {
let snapshot = self.sessions.session().snapshot();
let replacement_runtime = build_runtime(RuntimeBuildOptions {
provider: Arc::clone(self.provider.provider()),
tools: self.tools.tools(),
workspace: self.workspace.clone(),
workspace_policy: self.workspace_policy(),
approval_session: self
.approval_handler
.clone()
.map(rho_sdk::ApprovalSession::from_shared),
system_prompt: self.active_system_prompt(),
reasoning: self.provider.reasoning(),
service_tier: self.sessions.session().service_tier(),
compaction: self.compaction.clone(),
context_window: self.context_window,
usage_purpose: "agent",
usage_parent_session_id: None,
usage_recording: self.usage_recording.clone(),
hook_host_labels: rho_sdk::hooks::HookHostLabels::new(),
hooks: self.hooks.as_ref(),
})?;
let replacement_session = replacement_runtime
.rebind_session(SessionOptions::from_snapshot(snapshot))
.await?;
let previous_runtime = std::mem::replace(&mut self.runtime, replacement_runtime);
self.sessions.replace_runtime_session(replacement_session);
previous_runtime.shutdown();
Ok(())
}
}