Feat/compaction #20

raphaelmansuy · 2025-11-16T09:44:05Z

No description provided.

…ummarization - Introduced a new architectural decision record (ADR-009) detailing the implementation of session history compaction in `adk-code`. - Addressed issues of token budget exhaustion, database bloat, performance degradation, and cost escalation due to unbounded session histories. - Proposed a sliding window compaction mechanism that maintains immutability of original events while providing selective context for LLM interactions. - Defined a comprehensive architecture including components for compaction configuration, metadata handling, event selection, LLM summarization, and session service integration. - Established a mathematical model for triggering compaction based on invocation counts and token thresholds. - Outlined implementation phases and testing strategies to ensure robust integration and performance.

…tion using Agent's current LLM model

…dling

Copilot

Pull Request Overview

This PR implements session history compaction for the adk-code project to address unbounded token growth in long conversations. The implementation includes detailed ADR documentation and code changes across multiple layers.

Purpose: Enable 50+ turn agent workflows by automatically summarizing old conversation history, reducing token usage by 60-80% while preserving audit trails.

Key Changes:

New compaction package with sliding window algorithm using invocation-based thresholds
Wrapper pattern for session service to provide transparent event filtering
Integration with REPL, orchestration layer, and configuration system
New CLI flags and /compaction REPL command for configuration management

Reviewed Changes

Copilot reviewed 24 out of 24 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
`docs/adr/010-native-sdk-session-compaction.md`	ADR for upstream Google ADK Go SDK compaction (native EventActions approach)
`docs/adr/009-session-history-compaction.md`	ADR for adk-code-specific compaction using CustomMetadata workaround
`docs/adr/009-FEASIBILITY-REPORT.md`	Technical validation report confirming implementation feasibility
`docs/adr/0006-context-management.md`	Deleted - replaced by newer ADR-009 design
`adk-code/internal/session/compaction/types.go`	Core metadata types and helper functions for compaction events
`adk-code/internal/session/compaction/config.go`	Configuration structure with defaults matching ADR specs
`adk-code/internal/session/compaction/summarizer.go`	LLM-based summarization logic for event compaction
`adk-code/internal/session/compaction/selector.go`	Event selection algorithm for sliding window
`adk-code/internal/session/compaction/filtered_session.go`	Session wrapper implementing transparent event filtering
`adk-code/internal/session/compaction/service.go`	Service wrapper for compaction-aware session retrieval
`adk-code/internal/session/compaction/coordinator.go`	Orchestrates the compaction process
`adk-code/internal/session/compaction/compaction_test.go`	Unit tests for metadata storage and configuration
`adk-code/internal/session/manager.go`	Added WrapWithCompaction method for service wrapping
`adk-code/internal/repl/repl.go`	Integrated compaction trigger post-invocation with feedback display
`adk-code/internal/orchestration/session.go`	Modified initialization to create compaction coordinator
`adk-code/internal/orchestration/components.go`	Added compaction fields to SessionComponents
`adk-code/internal/orchestration/builder.go`	Updated builder to pass LLM to session initialization
`adk-code/internal/display/events/event.go`	Added compaction event detection and display
`adk-code/internal/config/config.go`	Added compaction configuration flags and fields
`adk-code/internal/cli/commands/repl_builders.go`	Updated help text with compaction documentation
`adk-code/internal/cli/commands/repl.go`	Added `/compaction` command handler
`adk-code/internal/cli/commands/interface.go`	Added CompactionCommand implementation
`adk-code/internal/cli/commands.go`	Updated command handler signature for appConfig
`adk-code/internal/app/app.go`	Passed config and session manager to REPL

Comments suppressed due to low confidence (1)

docs/adr/0006-context-management.md:1

This entire file is being deleted (ADR-0006), but the new implementation in ADR-009 and the code appears to be a different approach using CustomMetadata instead of the three-layer system described here. Consider if any valuable design insights from this ADR should be preserved in ADR-009, particularly around token tracking and output truncation.

adk-code/internal/display/events/event.go

Copilot · 2025-11-16T09:47:14Z

adk-code/internal/session/compaction/summarizer.go

+	responseStream := ls.llm.GenerateContent(ctx, llmRequest, false)
+	for resp := range responseStream {
+		if resp == nil {
+			continue
+		}
+		if resp.Content != nil {
+			summaryContent = resp.Content
+			usageMetadata = resp.UsageMetadata
+			break
+		}
+	}


Missing error handling: the response stream is iterated but resp.Err is never checked. If the LLM API call fails, this will result in nil content without surfacing the actual error to the caller.

@copilot open a new pull request to apply changes based on this feedback

adk-code/internal/session/compaction/summarizer.go

adk-code/internal/session/compaction/selector.go

Copilot · 2025-11-16T09:47:15Z

adk-code/internal/repl/repl.go

+	// Trigger compaction if enabled and conditions are met
+	if !hasError && r.config.SessionManager != nil && r.config.SessionManager.Coordinator != nil {
+		ctx := context.Background()
+
+		// Get the current session to pass to the coordinator
+		getResp, err := r.config.SessionManager.Manager.GetService().Get(ctx, &sessionpkg.GetRequest{
+			AppName:   "code_agent",
+			UserID:    r.config.UserID,
+			SessionID: r.config.SessionName,
+		})
+
+		if err == nil && getResp.Session != nil {
+			// Unwrap filtered session if necessary
+			sess := getResp.Session
+			if filtered, ok := sess.(*compaction.FilteredSession); ok {
+				sess = filtered.Underlying
+			}
+
+			// Create a spinner for compaction
+			compactionSpinner := display.NewSpinner(r.config.Renderer, "Compacting session history")
+			compactionSpinner.Start()
+
+			// Run compaction if thresholds are met
+			if compErr := r.config.SessionManager.Coordinator.RunCompaction(ctx, sess); compErr != nil {
+				// Log error but don't interrupt user experience
+				compactionSpinner.Stop()
+				fmt.Printf("%s Warning: Compaction failed: %v\n", r.config.Renderer.Yellow("⚠"), compErr)
+			} else {
+				// After compaction, check if an event was added and display feedback
+				// Get the session again to see the new compaction event
+				getResp2, err2 := r.config.SessionManager.Manager.GetService().Get(ctx, &sessionpkg.GetRequest{
+					AppName:   "code_agent",
+					UserID:    r.config.UserID,
+					SessionID: r.config.SessionName,
+				})
+
+				if err2 == nil && getResp2.Session != nil {
+					// Unwrap if needed
+					sess2 := getResp2.Session
+					if filtered, ok := sess2.(*compaction.FilteredSession); ok {
+						sess2 = filtered.Underlying
+					}
+
+					// Check if there's a recent compaction event
+					events := sess2.Events()
+					if events.Len() > 0 {
+						lastEvent := events.At(events.Len() - 1)
+						if lastEvent != nil && compaction.IsCompactionEvent(lastEvent) {
+							// Stop spinner with success
+							compactionSpinner.StopWithSuccess("Session history compacted")
+
+							// Display compaction notification
+							metadata, metaErr := compaction.GetCompactionMetadata(lastEvent)
+							if metaErr == nil {
+								fmt.Println()
+								fmt.Println(r.config.Renderer.Cyan("📦 Session History Compaction:"))
+								fmt.Printf("  %s Compacted %d events into 1 summary\n", r.config.Renderer.Dim("•"), metadata.EventCount)
+								fmt.Printf("  %s Token reduction: %d → %d tokens (%.1f%% compression)\n",
+									r.config.Renderer.Dim("•"),
+									metadata.OriginalTokens,
+									metadata.CompactedTokens,
+									metadata.CompressionRatio)
+								fmt.Printf("  %s Session context optimized for better performance\n", r.config.Renderer.Dim("•"))
+								fmt.Println()
+							} else {
+								compactionSpinner.Stop()
+							}
+						} else {
+							// No compaction event added (threshold not met)
+							compactionSpinner.Stop()
+						}
+					} else {
+						compactionSpinner.Stop()
+					}
+				} else {
+					compactionSpinner.Stop()
+				}
+			}
+		}
+	}


The compaction logic runs synchronously in the REPL main thread, which can cause a 1-5 second delay. According to ADR-009 line 801, this should be asynchronous to match Python ADK's behavior (asyncio.create_task()). The code should wrap this entire block in go func() { ... }() to avoid blocking the user.

@copilot open a new pull request to apply changes based on this feedback

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot · 2025-11-16T09:48:47Z

@raphaelmansuy I've opened a new pull request, #21, to work on those changes. Once the pull request is ready, I'll request review from you.

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot · 2025-11-16T09:49:26Z

@raphaelmansuy I've opened a new pull request, #22, to work on those changes. Once the pull request is ready, I'll request review from you.

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot · 2025-11-16T09:49:48Z

@raphaelmansuy I've opened a new pull request, #23, to work on those changes. Once the pull request is ready, I'll request review from you.

raphaelmansuy added 4 commits November 16, 2025 13:14

feat: update ADR-009 to reflect feasibility of session history compac…

de46d9e

…tion using Agent's current LLM model

Refactor code structure for improved readability and maintainability

a9eba89

style: format code for consistency in session components and repl han…

1bceb2a

…dling

raphaelmansuy requested a review from Copilot November 16, 2025 09:44

Copilot started reviewing on behalf of raphaelmansuy November 16, 2025 09:44 View session

Copilot finished reviewing on behalf of raphaelmansuy November 16, 2025 09:46

Copilot AI reviewed Nov 16, 2025

View reviewed changes

Update adk-code/internal/session/compaction/selector.go

6cc1c41

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot AI mentioned this pull request Nov 16, 2025

Make session history compaction asynchronous #21

Closed

raphaelmansuy and others added 2 commits November 16, 2025 17:48

Update adk-code/internal/session/compaction/summarizer.go

0ff4ff5

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Update adk-code/internal/session/compaction/summarizer.go

ac9b8ac

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot AI mentioned this pull request Nov 16, 2025

Fix missing error handling in LLM response stream iteration #22

Closed

Update adk-code/internal/display/events/event.go

14bfac4

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot AI mentioned this pull request Nov 16, 2025

Fix missing error handling in LLM response stream iteration #23

Closed

fix: correct parts initialization in LLM request for summarization

579fbfe

raphaelmansuy merged commit 56c1386 into main Nov 16, 2025
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