Copilot Plan vs Agent Mode Explained | Generated by AI

Home 2026.03

Question: When using GitHub Copilot, can we use Plan Mode or Agent Mode to help fix merge conflicts? Please introduce Plan Mode and explain how it differs from Agent Mode.

Answer:

GitHub Copilot: Plan Mode vs Agent Mode

Yes — both Plan Mode and Agent Mode in GitHub Copilot can assist with merge conflict resolution and complex multi-file fixes. Here is a full breakdown.

Overview: The Dual-Mode System

GitHub’s dual-mode approach separates thinking from doing: one mode drafts a concrete, auditable plan; the other reliably performs changes and validates them.

Plan Mode lets you review and approve a blueprint before the agent starts coding, while Agent Mode helps make changes at scale by analyzing code, proposing edits, running tests, and validating results across multiple files.

Plan Mode — What It Is

Plan Mode creates, refines, and executes step-by-step implementation plans. It analyzes your codebase, generates detailed execution plans, and validates that requirements are covered before starting to code.

The Plan agent enables you to create detailed implementation plans before starting implementation to ensure all requirements are met. With todo lists, the agent can ensure it stays focused on overall goals and tracks progress effectively.

How to activate Plan Mode in VS Code:

Open the Chat view (Ctrl+Alt+I) and select Plan from the agents dropdown. Alternatively, type /plan followed by your task description to switch to the Plan agent and start planning in one step.

How Planning works internally:

When a developer asks Copilot to perform a complex, multi-step task, it determines whether to respond directly or activate its planning mode. Simple prompts get quick answers, while multi-step ones trigger a coordinated plan. When invoked, Planning creates a Markdown file that defines the task, research steps, and progress updates as each execution step begins. As Copilot works, it revises and refines the plan — adapting to new context or results.

Plan Mode for merge conflicts:

This is ideal when you want to first review the strategy for resolving conflicts across multiple files — Copilot proposes which files to touch, what changes to make, and in what order, and you approve before any code changes.

Agent Mode — What It Is

Agent Mode lets you hand Copilot a high-level prompt and then watch as it autonomously plans the steps, selects the right files, runs tools or terminal commands, and iterates on code edits until the task is complete. It can reason across your entire project, take multi-step actions, and hold onto a significant amount of context across a session.

Instead of only rewriting lines you specify, Agent Mode analyzes related code, identifies additional changes that may be required, and applies them across the project to keep everything consistent.

Agent mode applies edits automatically rather than waiting for explicit approval at every step, while still surfacing any potentially risky commands for review before they run.

Agent Mode for merge conflicts:

You describe the conflict resolution goal in natural language, and Copilot autonomously edits all affected files, runs tests, and iterates until the task is complete — with minimal interruption.

Key Differences: Plan Mode vs Agent Mode

Dimension Plan Mode Agent Mode
Primary purpose Strategize & blueprint first Execute autonomously
Human control You approve the plan before execution Edits applied automatically; risky commands flagged
When code changes After you review & approve the plan Immediately and continuously
Best for Complex, risky, or multi-team tasks Well-defined tasks needing fast execution
Output A structured markdown plan + todo list Actual code changes across files
Transparency High — you see every step before it happens Moderate — you see results, not pre-approved steps
Ideal merge use case Planning conflict resolution strategy across many files Automatically fixing conflicts once strategy is clear

The best practice is to use both in sequence:

  1. Plan Mode first — Describe the merge conflict situation. Copilot generates a step-by-step plan showing which files have conflicts and how to resolve them. Review and edit the plan.
  2. Agent Mode second — Once the plan is approved, switch to Agent Mode (or let Copilot implement the plan), and it executes the changes automatically across all conflicting files.

Plan Mode gave a clear, editable blueprint before any code changed. Agent Mode executed multi-file edits, ran tests, and opened PRs faster than you could have scripted it by hand. Together, they felt like a reliable co-pilot instead of yet another tool.

When to Use Which

Use edit/plan mode when you want more granular control over the edits that Copilot proposes — for example, when you want to make a quick, specific update to a defined set of files, or want full control over the number of LLM requests used. Use Agent Mode when you have a specific task in mind and want to enable Copilot to autonomously edit your code — especially when your task is complex and involves multiple steps, iterations, and error handling.

Availability

Plan Mode telemetry is supported for JetBrains, Eclipse, Xcode, and VS Code Insiders at the enterprise, organization, and user level. General release for VS Code stable is expected soon.

As of March 2026, Agent Mode is generally available on both VS Code and JetBrains — a significant milestone, as it was previously VS Code only.

References:

Back Donate