Introduce signals change (#655)

* adding support for signals

* reducing false positives for signals like positive interaction

* adding docs. Still need to fix the messages list, but waiting on PR #621

* Improve frustration detection: normalize contractions and refine punctuation

* Further refine test cases with longer messages

* minor doc changes

* fixing echo statement for build

* fixing the messages construction and using the trait for signals

* update signals docs

* fixed some minor doc changes

* added more tests and fixed docuemtnation. PR 100% ready

* made fixes based on PR comments

* Optimize latency

1. replace sliding window approach with trigram containment check
2. add code to pre-compute ngrams for patterns

* removed some debug statements to make tests easier to read

* PR comments to make ObservableStreamProcessor accept optonal Vec<Messagges>

* fixed PR comments

---------

Co-authored-by: Salman Paracha <salmanparacha@MacBook-Pro-342.local>
Co-authored-by: MeiyuZhong <mariazhong9612@gmail.com>
Co-authored-by: nehcgs <54548843+nehcgs@users.noreply.github.com>

crates/brightstaff/src/handlers/llm.rs

@@ -111,6 +111,9 @@ pub async fn llm_chat(
         .get_recent_user_message()
         .map(|msg| truncate_message(&msg, 50));
 
+    // Extract messages for signal analysis (clone before moving client_request)
+    let messages_for_signals = client_request.get_messages();
+
     client_request.set_model(resolved_model.clone());
     if client_request.remove_metadata_key("archgw_preference_config") {
         debug!(
@@ -292,6 +295,7 @@ pub async fn llm_chat(
         operation_component::LLM,
         llm_span,
         request_start_time,
+        Some(messages_for_signals),
     );
 
     // === v1/responses state management: Wrap with ResponsesStateProcessor ===

crates/brightstaff/src/handlers/utils.rs

@@ -10,8 +10,10 @@ use tokio_stream::wrappers::ReceiverStream;
 use tokio_stream::StreamExt;
 use tracing::warn;
 
-// Import tracing constants
-use crate::tracing::{error, llm};
+// Import tracing constants and signals
+use crate::signals::{InteractionQuality, SignalAnalyzer, TextBasedSignalAnalyzer, FLAG_MARKER};
+use crate::tracing::{error, llm, signals as signal_constants};
+use hermesllm::apis::openai::Message;
 
 /// Trait for processing streaming chunks
 /// Implementors can inject custom logic during streaming (e.g., hallucination detection, logging)
@@ -38,6 +40,7 @@ pub struct ObservableStreamProcessor {
     chunk_count: usize,
     start_time: Instant,
     time_to_first_token: Option<u128>,
+    messages: Option<Vec<Message>>,
 }
 
 impl ObservableStreamProcessor {
@@ -48,11 +51,13 @@ impl ObservableStreamProcessor {
     /// * `service_name` - The service name for this span (e.g., "archgw(llm)")
     /// * `span` - The span to finalize after streaming completes
     /// * `start_time` - When the request started (for duration calculation)
+    /// * `messages` - Optional conversation messages for signal analysis
     pub fn new(
         collector: Arc<TraceCollector>,
         service_name: impl Into<String>,
         span: Span,
         start_time: Instant,
+        messages: Option<Vec<Message>>,
     ) -> Self {
         Self {
             collector,
@@ -62,6 +67,7 @@ impl ObservableStreamProcessor {
             chunk_count: 0,
             start_time,
             time_to_first_token: None,
+            messages,
         }
     }
 }
@@ -133,6 +139,94 @@ impl StreamProcessor for ObservableStreamProcessor {
             }
         }
 
+        // Analyze signals if messages are available and add to span attributes
+        if let Some(ref messages) = self.messages {
+            let analyzer: Box<dyn SignalAnalyzer> = Box::new(TextBasedSignalAnalyzer::new());
+            let report = analyzer.analyze(messages);
+
+            // Add overall quality
+            self.span.attributes.push(Attribute {
+                key: signal_constants::QUALITY.to_string(),
+                value: AttributeValue {
+                    string_value: Some(format!("{:?}", report.overall_quality)),
+                },
+            });
+
+            // Add repair/follow-up metrics if concerning
+            if report.follow_up.is_concerning || report.follow_up.repair_count > 0 {
+                self.span.attributes.push(Attribute {
+                    key: signal_constants::REPAIR_COUNT.to_string(),
+                    value: AttributeValue {
+                        string_value: Some(report.follow_up.repair_count.to_string()),
+                    },
+                });
+
+                self.span.attributes.push(Attribute {
+                    key: signal_constants::REPAIR_RATIO.to_string(),
+                    value: AttributeValue {
+                        string_value: Some(format!("{:.3}", report.follow_up.repair_ratio)),
+                    },
+                });
+            }
+
+            // Add flag marker to operation name if any concerning signal is detected
+            let should_flag = report.frustration.has_frustration
+                || report.repetition.has_looping
+                || report.escalation.escalation_requested
+                || matches!(
+                    report.overall_quality,
+                    InteractionQuality::Poor | InteractionQuality::Severe
+                );
+
+            if should_flag {
+                // Prepend flag marker to the operation name
+                self.span.name = format!("{} {}", self.span.name, FLAG_MARKER);
+            }
+
+            // Add key signal metrics
+            if report.frustration.has_frustration {
+                self.span.attributes.push(Attribute {
+                    key: signal_constants::FRUSTRATION_COUNT.to_string(),
+                    value: AttributeValue {
+                        string_value: Some(report.frustration.frustration_count.to_string()),
+                    },
+                });
+                self.span.attributes.push(Attribute {
+                    key: signal_constants::FRUSTRATION_SEVERITY.to_string(),
+                    value: AttributeValue {
+                        string_value: Some(report.frustration.severity.to_string()),
+                    },
+                });
+            }
+
+            if report.repetition.has_looping {
+                self.span.attributes.push(Attribute {
+                    key: signal_constants::REPETITION_COUNT.to_string(),
+                    value: AttributeValue {
+                        string_value: Some(report.repetition.repetition_count.to_string()),
+                    },
+                });
+            }
+
+            if report.escalation.escalation_requested {
+                self.span.attributes.push(Attribute {
+                    key: signal_constants::ESCALATION_REQUESTED.to_string(),
+                    value: AttributeValue {
+                        string_value: Some("true".to_string()),
+                    },
+                });
+            }
+
+            if report.positive_feedback.has_positive_feedback {
+                self.span.attributes.push(Attribute {
+                    key: signal_constants::POSITIVE_FEEDBACK_COUNT.to_string(),
+                    value: AttributeValue {
+                        string_value: Some(report.positive_feedback.positive_count.to_string()),
+                    },
+                });
+            }
+        }
+
         // Record the finalized span
         self.collector
             .record_span(&self.service_name, self.span.clone());

crates/brightstaff/src/lib.rs

@@ -1,5 +1,6 @@
 pub mod handlers;
 pub mod router;
+pub mod signals;
 pub mod state;
 pub mod tracing;
 pub mod utils;

crates/brightstaff/src/signals/mod.rs

@@ -0,0 +1,3 @@
+mod analyzer;
+
+pub use analyzer::*;

crates/brightstaff/src/tracing/constants.rs

@@ -139,6 +139,45 @@ pub mod error {
     pub const STACK_TRACE: &str = "error.stack_trace";
 }
 
+// =============================================================================
+// Span Attributes - Agentic Signals
+// =============================================================================
+
+/// Behavioral quality indicators for agent interactions
+/// These signals are computed automatically from conversation patterns
+pub mod signals {
+    /// Overall quality assessment
+    /// Values: "Excellent", "Good", "Neutral", "Poor", "Severe"
+    pub const QUALITY: &str = "signals.quality";
+
+    /// Total number of turns in the conversation
+    pub const TURN_COUNT: &str = "signals.turn_count";
+
+    /// Efficiency score (0.0-1.0)
+    pub const EFFICIENCY_SCORE: &str = "signals.efficiency_score";
+
+    /// Number of repair attempts detected
+    pub const REPAIR_COUNT: &str = "signals.follow_up.repair.count";
+
+    /// Ratio of repairs to user turns
+    pub const REPAIR_RATIO: &str = "signals.follow_up.repair.ratio";
+
+    /// Number of frustration indicators detected
+    pub const FRUSTRATION_COUNT: &str = "signals.frustration.count";
+
+    /// Frustration severity level (0-3)
+    pub const FRUSTRATION_SEVERITY: &str = "signals.frustration.severity";
+
+    /// Number of repetition instances detected
+    pub const REPETITION_COUNT: &str = "signals.repetition.count";
+
+    /// Whether escalation was requested (user asked for human help)
+    pub const ESCALATION_REQUESTED: &str = "signals.escalation.requested";
+
+    /// Number of positive feedback indicators detected
+    pub const POSITIVE_FEEDBACK_COUNT: &str = "signals.positive_feedback.count";
+}
+
 // =============================================================================
 // Operation Names
 // =============================================================================

crates/brightstaff/src/tracing/mod.rs

@@ -1,3 +1,5 @@
 mod constants;
 
-pub use constants::{error, http, llm, operation_component, routing, OperationNameBuilder};
+pub use constants::{
+    error, http, llm, operation_component, routing, signals, OperationNameBuilder,
+};