Skip to content

.NET: Add context window size compaction strategy for harness - #5304

Merged
westey (westey-m) merged 3 commits into
microsoft:feature-harnessfrom
westey-m:harness-compaction
Apr 16, 2026
Merged

.NET: Add context window size compaction strategy for harness#5304
westey (westey-m) merged 3 commits into
microsoft:feature-harnessfrom
westey-m:harness-compaction

Conversation

@westey-m

@westey-mwestey (westey-m) commented Apr 16, 2026

Copy link
Copy Markdown
Contributor

Motivation and Context

Adding an opinionated compaction strategy that is easy to use based on context window size.

Description

  • Add context window size compaction strategy for harness

Contribution Checklist

  • The code builds clean without any errors or warnings
  • The PR follows the Contribution Guidelines
  • All unit tests pass, and I have added new tests where possible
  • Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

CopilotAI review requested due to automatic review settings April 16, 2026 11:13
@moonbox3Evan Mattson (moonbox3) added the .NET Usage: [Issues, PRs], Target: .Net label Apr 16, 2026
@github-actionsgithub-actionsBot changed the title Add context window size compaction strategy for harness.NET: Add context window size compaction strategy for harnessApr 16, 2026
CopilotAI reviewed Apr 16, 2026
View reviewed changes

CopilotAI left a comment

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview

Adds an opinionated “context window size”-driven compaction strategy to the .NET Agent Framework and wires it into the Harness research sample to keep long-running sessions within token budgets.

Changes:

  • Introduces ContextWindowCompactionStrategy, which derives tool-eviction and truncation triggers from (maxContextWindowTokens - maxOutputTokens).
  • Adds unit tests covering constructor validation and basic compaction behavior.
  • Updates the Harness Step01 Research sample to use the new compaction strategy and display token usage breakdown during streaming.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 8 comments.

Show a summary per file
FileDescription
dotnet/src/Microsoft.Agents.AI/Compaction/ContextWindowCompactionStrategy.csNew strategy wrapping a compaction pipeline with thresholds computed from context window and output limits.
dotnet/tests/Microsoft.Agents.AI.UnitTests/Compaction/ContextWindowCompactionStrategyTests.csNew unit tests for constructor validation and compacting behavior.
dotnet/samples/02-agents/Harness/Harness_Step01_Research/Program.csUses the new strategy in the Harness sample; switches to Foundry endpoint env var and configures local history reduction.
dotnet/samples/02-agents/Harness/Harness_Step01_Research/Harness_Step01_Research.csprojAdds a project reference needed for OpenAI Responses extensions used by the sample.
dotnet/samples/02-agents/Harness/Harness_Shared_Console/HarnessConsole.csEnhances streaming console output to show token usage/reasoning and adds optional context-window parameters.

Comment threaddotnet/samples/02-agents/Harness/Harness_Step01_Research/Program.cs
Comment threaddotnet/tests/Microsoft.Agents.AI.UnitTests/Compaction/ContextWindowCompactionStrategyTests.cs Outdated
Comment threaddotnet/tests/Microsoft.Agents.AI.UnitTests/Compaction/ContextWindowCompactionStrategyTests.cs Outdated
Comment threaddotnet/src/Microsoft.Agents.AI/Compaction/ContextWindowCompactionStrategy.cs Outdated
Comment threaddotnet/samples/02-agents/Harness/Harness_Shared_Console/HarnessConsole.cs Outdated
Comment threaddotnet/samples/02-agents/Harness/Harness_Shared_Console/HarnessConsole.cs
Comment threaddotnet/samples/02-agents/Harness/Harness_Shared_Console/HarnessConsole.cs
Comment threaddotnet/src/Microsoft.Agents.AI/Compaction/ContextWindowCompactionStrategy.cs Outdated
rogerbarreto
Roger Barreto (rogerbarreto) reviewed Apr 16, 2026
View reviewed changes
Comment threaddotnet/samples/02-agents/Harness/Harness_Step01_Research/Program.cs Outdated
@westey-m
Apply suggestions from code review
1cf669c
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
westey-m
westey (westey-m) commented Apr 16, 2026
View reviewed changes

@westey-mwestey (westey-m) left a comment

Copy link
Copy Markdown
ContributorAuthor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Replying to open review comments with fixes applied — see individual thread replies below.

@moonbox3Evan Mattson (moonbox3) added the documentation Usage: [Issues, PRs], Target: documentation in the code base and learn docs label Apr 16, 2026
@westey-m
westey (westey-m) merged commit d0ac1d8 into microsoft:feature-harnessApr 16, 2026
13 checks passed
pullBot pushed a commit to nagyist/ms-agent-framework that referenced this pull request May 1, 2026
@westey-m@rogerbarreto
.NET: Harness Feature branch (microsoft#5310)
626b418
* .NET: Add a TODO AIContextProvider (microsoft#5233)
* Add a TODO AIContextProvider
* Add unit tests
* Address PR comments
* Address PR comments
* Fix test after removing one tool
* .NET: Add a ModeProvider for managing agent modes (microsoft#5247)
* Add a ModeProvider for managing agent modes
* Fix typo
* Fix typo
* Fix typo
* Address PR comments
* .NET: Add sample to show how to build a harness (microsoft#5268)
* Add sample to show how to build a harness
* Improve sample
* Sample max output tokens and model
* Fix encoding
* Fix model name in readme
* Address PR comments
* .NET: Add context window size compaction strategy for harness (microsoft#5304)
* Add context window size compaction strategy for harness
* Apply suggestions from code review
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
* Address PR comments
---------
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
* .NET: Add a file memory provider (microsoft#5315)
* Add a file memory provider
* Address PR comments
* Fix review comments.
* Add additional unit tests
* Addressing PR comments.
* .NET: Harness: Improve prompts and add FileSystem store (microsoft#5365)
* Harness: Improve prompts and add FileSystem store
* Address PR comments
* .NET: Harness: Improve path validation (microsoft#5404)
* Harness: Improve path validation
* Address PR comments
* .NET: Add always approve helpers, improve sample and fix bug (microsoft#5451)
* Add always approve helpers, improve sample and fix bug
* Address PR comments
* .NET: Make Todo, Mode and FileMemory providers more configurable (microsoft#5477)
* Make Todo, Mode and FileMemory providers more configurable
* Address PR comments.
* .NET: Add subagents provider and sample (microsoft#5518)
* Add subagents provider and sample
* Addressing PR comments.
* .NET: Harness filememory index plus instructions consistency (microsoft#5540)
* Add FileMemoryProvider index and improve instruction consistency
* Address PR comments.
* Address PR comments
* Address PR comments.
* Apply suggestion from @rogerbarreto
Co-authored-by: Roger Barreto <19890735+rogerbarreto@users.noreply.github.com>
---------
Co-authored-by: Roger Barreto <19890735+rogerbarreto@users.noreply.github.com>
* .NET: Refactor harness console to be more extensible and easy to understand with better UX (microsoft#5573)
* Refactor harness console to be more extensible and easy to understand with better UX.
* Fix formatting issues.
* Allow multiple clarifications in one response
* Address PR comments
* .NET: Add FileAccessProvdider and concurrency fix for FileMemoryProvider (microsoft#5583)
* Add FileAccessProvdider and concurrency fix for FileMemoryProvider
* Address PR comments
---------
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Roger Barreto <19890735+rogerbarreto@users.noreply.github.com>
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

Copilot code reviewCopilot
Copilot review effort
Applies to this pull request for everyone.Learn more about Copilot code review.
Copilot left review comments
@rogerbarretoRoger Barreto (rogerbarreto)rogerbarreto approved these changes
@peibekwePeter Ibekwe (peibekwe)peibekwe approved these changes
+1 more reviewer
@lokitothJacob Alber (lokitoth)lokitoth approved these changes
Reviewers whose approvals may not affect merge requirements

Assignees

No one assigned

Labels

documentationUsage: [Issues, PRs], Target: documentation in the code base and learn docs.NETUsage: [Issues, PRs], Target: .Net

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

6 participants

@westey-m@lokitoth@rogerbarreto@peibekwe@moonbox3