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GitHub Copilot Complete Guide

GitHub Copilot Reasoning Levels Guide — Low/Medium/High/x-High and AI Credits

For / Key Points

For: GitHub Copilot (Pro/Pro+/Enterprise) users who want to understand what the reasoning level selector actually controls

Key Points:

  • Reasoning levels control how much the model "thinks" — same model, different thinking token budgets
  • Under usage-based billing after June 2026, higher reasoning levels can consume more AI Credits
  • Start with defaults, then raise effort for design decisions, multi-file work, and debugging

What Are Reasoning Levels?

VS Code 1.113 (March 25, 2026) introduced the Thinking Effort selector — a control that adjusts how deeply the model reasons before generating a response. Today, the model picker is the primary control surface, and the old github.copilot.chat.responsesApiReasoningEffort setting is deprecated.1

The model picker shows a submenu with levels such as Low / Medium / High when a selected model supports reasoning. Available levels vary by model and surface. Non-reasoning models do not show the Thinking Effort submenu.

The key point: changing the reasoning level does not change the model itself. The same GPT-5.4 at Low produces a minimal reasoning chain for an instant response, while at x-High it allocates significantly more thinking tokens for deeper analysis.

Supported Models and Levels

Model familyThinking EffortPractical judgment
GPT-5.4 / GPT-5.3-Codex and similar reasoning modelsAvailable when supportedComplex design and debugging
Claude Sonnet / Opus reasoning modelsAvailable when supportedQuality-focused implementation and review
GPT-4.1 / GPT-4o / GPT-5 mini and similar modelsOften not shownLightweight questions and routine chat
Claude Haiku / Gemini Flash and similar modelsOften not shownSpeed- and cost-sensitive work

Unsupported models (no reasoning level selector):

  • GPT-4.1, GPT-4o, GPT-5 mini — non-reasoning models
  • Claude Haiku 4.5, Gemini 3 Flash — speed-optimized

Do not freeze this as a static model table

GitHub Copilot models, extended context, and reasoning controls change quickly. Prefer the live model picker and official model documentation over static model names in this article.3

Cost: Reasoning Level Now Matters for AI Credits

This is the most important fact.

Under usage-based billing after June 2026, raising reasoning effort can increase AI Credits consumption.

GitHub explains Copilot cost as a function of the model and token consumption: input tokens, output tokens, and cached context are converted into AI Credits. GitHub's June 4, 2026 changelog also states that larger context windows or higher reasoning levels consume more AI Credits per interaction.23

In the legacy premium request model, it was sometimes reasonable to say "same model, same request multiplier." In the current AI Credits model, the same model can cost more if higher effort creates more thinking tokens or output.

Cost lensLegacy premium requestsAI Credits after June 2026
UnitRequest count and model multiplierModel price, input, output, cached context, thinking tokens
High effortOften treated as the same multiplier for the same modelCan increase per-interaction consumption
Savings tacticReduce round tripsReduce round trips, context size, and unnecessary effort

So High is not a free quality switch. Use it when the task justifies deeper reasoning, but do not pin every lightweight chat to High or x-High.

What Each Level Actually Does

LevelBehaviorLatencyBest For
LowMinimal reasoning. Instant responseFastestBoilerplate, syntax questions
Medium / defaultBalancedFastGeneral coding
HighDeep reasoning chainSlightly slowerRefactoring, design decisions
x-High / extended thinkingHighest reasoning budgetSlowest and more likely to consume creditsSecurity audits, large migrations

Watch Credit Consumption, Not Only Speed

Higher effort can improve results on complex work. The VS Code AI Credits optimization guide also warns that higher effort produces more thinking tokens, increasing both latency and credit consumption.4

Low is genuinely faster, but response quality drops noticeably on certain tasks. Multi-file refactoring at Low, for example, can miss cross-file dependencies.

When to Raise Effort

Raise effort based on quality risk.

SituationRecommendation
Naming, simple API questions, short explanationsDefault or lightweight model
Small one- or two-file editsStart with default, raise only if it fails
Multi-file refactoringConsider High
Security review, migration design, incident analysisConsider High or above
Long logs or repository-wide contextNarrow the scope first, then raise effort only if needed

The key step is narrowing scope before raising effort. If you send a large context window and also raise effort, quality may improve, but AI Credits consumption is more likely to rise too.

Does Low Have a Place?

Yes, but it's limited.

Low works well for:

  • Simple code completions and snippet generation
  • "What's the signature for this function?" type questions
  • Rapid feedback loops during prototyping
  • Auto-generating doc comments

Avoid Low for:

  • Multi-file refactoring
  • Security review and vulnerability analysis
  • DB schema changes or framework migrations
  • Architecture decisions

The rule is simple: tasks that don't require thinking → Low or default. Tasks that need real reasoning → High or above.

But "when in doubt, use High" is no longer the right cost default. If you care about AI Credits, start with the default and raise effort only when the result is not good enough.

Use task-based switching, not always-on High.

  1. Use defaults for routine chat, small edits, and explanation tasks.
  2. Use High for design decisions, multi-file edits, and root-cause analysis.
  3. Reserve x-High or extended thinking for security audits, large migrations, or failed prior attempts.
  4. Before combining long context with High effort, trim files, logs, and task scope.

Switch from the model picker

VS Code 1.113+ lets you switch Thinking Effort from the model picker for supported models. Prefer checking the UI per task instead of pinning the deprecated settings.json setting.

For broader cost design, read GitHub Copilot AI Credits Optimization.

Summary

  • Reasoning levels control how much the model "thinks." The model itself doesn't change
  • Under AI Credits, higher reasoning levels can consume more credits
  • High is worth using for complex work where quality risk is high
  • Start routine work at the default, then raise effort only when needed

Reasoning effort is a quality control. It is also a credit-consumption control. Treat it as a per-task decision, not a permanent maximum setting.

References