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Chris Rickman
2026-03-05 01:48:40 -08:00
parent fcd60daed5
commit eb8406214e
27 changed files with 1450 additions and 576 deletions
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dotnet/src/Microsoft.Agents.AI/Compaction/SummarizationCompactionStrategy.cs
+73 -31
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@@ -1,5 +1,7 @@
// Copyright (c) Microsoft. All rights reserved.
using System;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
@@ -9,36 +11,62 @@ using Microsoft.Shared.Diagnostics;
namespace Microsoft.Agents.AI.Compaction;
/// <summary>
/// A compaction strategy that summarizes older message groups using an <see cref="IChatClient"/>,
/// replacing them with a single summary message.
/// A compaction strategy that uses an LLM to summarize older portions of the conversation,
/// replacing them with a single summary message that preserves key facts and context.
/// </summary>
/// <remarks>
/// <para>
/// When the number of included message groups exceeds <see cref="MaxGroupsBeforeSummary"/>,
/// this strategy extracts the oldest non-system groups (up to the threshold), sends them
/// to an <see cref="IChatClient"/> for summarization, and replaces those groups with a single
/// assistant message containing the summary.
/// This strategy protects system messages and the most recent <see cref="PreserveRecentGroups"/>
/// non-system groups. All older groups are collected and sent to the <see cref="IChatClient"/>
/// for summarization. The resulting summary replaces those messages as a single assistant message
/// with <see cref="MessageGroupKind.Summary"/>.
/// </para>
/// <para>
/// System message groups are always preserved and never included in summarization.
/// The <see cref="CompactionTrigger"/> predicate controls when compaction proceeds.
/// When <see langword="null"/>, the strategy compacts whenever there are groups older than the preserve window.
/// Use <see cref="CompactionTriggers"/> for common trigger conditions such as token thresholds.
/// </para>
/// </remarks>
public sealed class SummarizationCompactionStrategy : ICompactionStrategy
public sealed class SummarizationCompactionStrategy : CompactionStrategy
{
private const string DefaultSummarizationPrompt =
"Summarize the following conversation concisely, preserving key facts, decisions, and context. " +
"Focus on information that would be needed to continue the conversation effectively.";
/// <summary>
/// The default summarization prompt used when none is provided.
/// </summary>
public const string DefaultSummarizationPrompt =
"""
You are a conversation summarizer. Produce a concise summary of the conversation that preserves:
- Key facts, decisions, and user preferences
- Important context needed for future turns
- Tool call outcomes and their significance
Omit pleasantries and redundant exchanges. Be factual and brief.
""";
/// <summary>
/// Initializes a new instance of the <see cref="SummarizationCompactionStrategy"/> class.
/// </summary>
/// <param name="chatClient">The chat client to use for generating summaries.</param>
/// <param name="maxGroupsBeforeSummary">The maximum number of included groups allowed before summarization is triggered.</param>
/// <param name="summarizationPrompt">Optional custom prompt for the summarization request. If <see langword="null"/>, a default prompt is used.</param>
public SummarizationCompactionStrategy(IChatClient chatClient, int maxGroupsBeforeSummary, string? summarizationPrompt = null)
/// <param name="chatClient">The <see cref="IChatClient"/> to use for generating summaries. A smaller, faster model is recommended.</param>
/// <param name="trigger">
/// The <see cref="CompactionTrigger"/> that controls when compaction proceeds.
/// </param>
/// <param name="preserveRecentGroups">
/// The number of most-recent non-system message groups to protect from summarization.
/// Defaults to 4, preserving the current and recent exchanges.
/// </param>
/// <param name="summarizationPrompt">
/// An optional custom system prompt for the summarization LLM call. When <see langword="null"/>,
/// <see cref="DefaultSummarizationPrompt"/> is used.
/// </param>
public SummarizationCompactionStrategy(
IChatClient chatClient,
CompactionTrigger trigger,
int preserveRecentGroups = 4,
string? summarizationPrompt = null)
: base(trigger)
{
this.ChatClient = Throw.IfNull(chatClient);
this.MaxGroupsBeforeSummary = maxGroupsBeforeSummary;
this.PreserveRecentGroups = preserveRecentGroups;
this.SummarizationPrompt = summarizationPrompt ?? DefaultSummarizationPrompt;
}
@@ -48,9 +76,9 @@ public sealed class SummarizationCompactionStrategy : ICompactionStrategy
public IChatClient ChatClient { get; }
/// <summary>
/// Gets the maximum number of included groups allowed before summarization is triggered.
/// Gets the number of most-recent non-system groups to protect from summarization.
/// </summary>
public int MaxGroupsBeforeSummary { get; }
public int PreserveRecentGroups { get; }
/// <summary>
/// Gets the prompt used when requesting summaries from the chat client.
@@ -58,25 +86,35 @@ public sealed class SummarizationCompactionStrategy : ICompactionStrategy
public string SummarizationPrompt { get; }
/// <inheritdoc/>
public async Task<bool> CompactAsync(MessageIndex groups, CancellationToken cancellationToken = default)
protected override async Task<bool> ApplyCompactionAsync(MessageIndex index, CancellationToken cancellationToken)
{
int includedCount = groups.IncludedGroupCount;
if (includedCount <= this.MaxGroupsBeforeSummary)
// Count non-system, non-excluded groups to determine which are protected
int nonSystemIncludedCount = 0;
for (int i = 0; i < index.Groups.Count; i++)
{
MessageGroup group = index.Groups[i];
if (!group.IsExcluded && group.Kind != MessageGroupKind.System)
{
nonSystemIncludedCount++;
}
}
int protectedFromEnd = Math.Min(this.PreserveRecentGroups, nonSystemIncludedCount);
int groupsToSummarize = nonSystemIncludedCount - protectedFromEnd;
if (groupsToSummarize <= 0)
{
return false;
}
// Determine how many groups to summarize (keep the most recent MaxGroupsBeforeSummary groups)
int groupsToSummarize = includedCount - this.MaxGroupsBeforeSummary;
// Collect the oldest non-system included groups for summarization
StringBuilder conversationText = new();
int summarized = 0;
int insertIndex = -1;
for (int i = 0; i < groups.Groups.Count && summarized < groupsToSummarize; i++)
for (int i = 0; i < index.Groups.Count && summarized < groupsToSummarize; i++)
{
MessageGroup group = groups.Groups[i];
MessageGroup group = index.Groups[i];
if (group.IsExcluded || group.Kind == MessageGroupKind.System)
{
continue;
@@ -98,7 +136,7 @@ public sealed class SummarizationCompactionStrategy : ICompactionStrategy
}
group.IsExcluded = true;
group.ExcludeReason = "Summarized by SummarizationCompactionStrategy";
group.ExcludeReason = $"Summarized by {nameof(SummarizationCompactionStrategy)}";
summarized++;
}
@@ -111,23 +149,27 @@ public sealed class SummarizationCompactionStrategy : ICompactionStrategy
ChatResponse response = await this.ChatClient.GetResponseAsync(
[
new ChatMessage(ChatRole.System, this.SummarizationPrompt),
.. index.Groups
.Where(g => !g.IsExcluded && g.Kind == MessageGroupKind.System)
.SelectMany(g => g.Messages),
new ChatMessage(ChatRole.User, conversationText.ToString()),
new ChatMessage(ChatRole.User, "Summarize the conversation above concisely."),
],
cancellationToken: cancellationToken).ConfigureAwait(false);
string summaryText = response.Text ?? string.Empty;
string summaryText = string.IsNullOrWhiteSpace(response.Text) ? "[Summary unavailable]" : response.Text;
// Insert a summary group at the position of the first summarized group
ChatMessage summaryMessage = new(ChatRole.Assistant, $"[Summary of earlier conversation]: {summaryText}");
ChatMessage summaryMessage = new(ChatRole.Assistant, $"[Summary]\n{summaryText}");
(summaryMessage.AdditionalProperties ??= [])[MessageGroup.SummaryPropertyKey] = true;
if (insertIndex >= 0)
{
groups.InsertGroup(insertIndex, MessageGroupKind.Summary, [summaryMessage]);
index.InsertGroup(insertIndex, MessageGroupKind.Summary, [summaryMessage]);
}
else
{
groups.AddGroup(MessageGroupKind.Summary, [summaryMessage]);
index.AddGroup(MessageGroupKind.Summary, [summaryMessage]);
}
return true;