[dotnet-port] Align agentmode tool names and instructions with .NET

[github-actions]

Summary

Aligns the agent/harness/agentmode package with the .NET AgentModeProvider as updated in microsoft/agent-framework#6071.

Changes made:

1. Tool names renamed — AgentMode_Set/AgentMode_Get → mode_set/mode_get. This matches the cross-SDK alignment made in #6071 (also applied to the Python SDK at the same time).

2. Default instructions updated — the instructions now:

   • Add a bullet note: "you must check the current mode after any user input" (important behavioral guidance).
   • Reference mode_get/mode_set instead of the old tool names.
   • Add a "Mandatory Mode based Workflow" section that guides the agent on mode-based behavior for every user request.

3. Default mode descriptions expanded — plan and execute now have detailed step-by-step process descriptions matching .NET. Previously both descriptions were a single short sentence; now each has a 5–7 step workflow.

4. Mode rendering format — buildInstructions now formats each mode as a markdown section header (#### mode_name) followed by its description, matching .NET's BuildInstructions output. The old format used bullet points (- "mode_name": description).

5. Tests updated — existing TestToolNames updated for new names; two new tests added:

   • TestDefaultInstructions_ContainToolNamesAndModeCheckGuidance — verifies mode_get, mode_set, "check the current mode", and "Mandatory Mode based Workflow" are present.
   • TestDefaultInstructions_ModesSectionHeaderFormat — verifies #### plan / #### execute headers appear in instructions.

6. Feature comparison doc updated to note the alignment.

Ported .NET PRs

• Python: Align ModeProvider tool names and instructions agent-framework#6071 — "Python: Align ModeProvider tool names and instructions" (also updated .NET AgentModeProvider tool names AgentMode_Set→mode_set, AgentMode_Get→mode_get, plus instructions and default mode descriptions)

Breaking Changes

Yes. The mode_set and mode_get tool names replace AgentMode_Set and AgentMode_Get. Any agent prompts or harness configurations that reference the old tool names by string will stop matching. Since this is an intentional cross-SDK alignment (same rename was applied to Python) and the Go SDK is in beta, this breaking change is acceptable.

Tests and Examples

• All existing agent/harness/agentmode tests pass.
• Full go test ./... passes.
• Added TestDefaultInstructions_ContainToolNamesAndModeCheckGuidance.
• Added TestDefaultInstructions_ModesSectionHeaderFormat.

Notes

Upstream commits 5e097276 (docs), 383d551b (Purview), 2a345e5d (Magentic), 96d242fa (HarnessAgent compaction opt-in), and 9486c76e (ChatClientAgent reasoning merging) were inspected but are not applicable to the Go SDK — no Go equivalents for Magentic, HarnessAgent, or ChatClientAgent exist. The AgentMode misalignment was found via the Go SDK misalignment pass.

Generated by .NET to Go Porting Agent · ● 53.9M · ◷

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Show patch preview (194 of 194 lines)

From 754d86f885b076c995c80469f6121e7c2ce828e3 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Wed, 10 Jun 2026 10:32:03 +0000
Subject: [PATCH] harness/agentmode: align tool names and instructions with
 .NET (#6071)

Rename AgentMode_Set/AgentMode_Get tools to mode_set/mode_get to match
the cross-SDK alignment made in microsoft/agent-framework#6071.

Also update the default instructions and default mode descriptions to
match the .NET AgentModeProvider as of that same PR:
- Add 'check mode after user input' note to instructions.
- Add 'Mandatory Mode based Workflow' section.
- Expand plan/execute default mode descriptions with step-by-step processes.
- Change mode rendering in instructions from bullet points to section
  headers (#### mode_name) matching .NET BuildInstructions output.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 agent/harness/agentmode/agentmode.go      | 52 +++++++++++++++++------
 agent/harness/agentmode/agentmode_test.go | 45 ++++++++++++++++++--
 docs/dotnet-go-sdk-feature-comparison.md  |  2 +-
 3 files changed, 81 insertions(+), 18 deletions(-)

diff --git a/agent/harness/agentmode/agentmode.go b/agent/harness/agentmode/agentmode.go
index 2d4201af..7c0df6a5 100644
--- a/agent/harness/agentmode/agentmode.go
+++ b/agent/harness/agentmode/agentmode.go
@@ -25,14 +25,20 @@ const stateKey = "agentModeState"
 
 const defaultInstructions = `## Agent Mode
 
-You can operate in different modes. Depending on the mode you are in, you will be required to follow different processes.
+- You can operate in different modes. Depending on the mode you are in, you will be required to follow different processes.
+- You must check the current mode after any user input, since the user may have changed the mode themselves,
+  e.g. the user may have switched to 'plan' mode after a previous research task finished in 'execute' mode, meaning they want to review a plan first before execu
... (truncated)