When to use Claude Code vs Cursor vs Codex (a decision tree)

Claude Code, Cursor, and Codex (Copilot) all do AI-assisted coding, but they optimize for different shapes of work. Picking the right tool per task saves real time. This is the decision tree we use behind mq-dir's development.

TL;DR decision tree

Task takes <2 minutes, you know what to change?
  → Cursor (inline edit)

Task spans 5+ files, has multiple steps?
  → Claude Code (delegated)

Task is single-file completion as you type?
  → Codex / Copilot (autocomplete)

Task is "something is broken, find and fix"?
  → Claude Code (delegation + investigation)

Task is "add this feature, follow the patterns"?
  → Cursor for short, Claude Code for long

Task is reviewing a PR?
  → Cursor's chat or a dedicated review tool, not Codex

What each one is

Cursor — IDE with AI inside

VS Code fork with deep AI integration. Inline edits, tab autocomplete, agent mode for multi-step. Your default editor with AI everywhere.

Best at: editor-flow tasks. You're in a file, you know what to change, you ask the AI to do it.

Pricing: $20/mo Pro, $40/mo Business.

Claude Code — Terminal-based agent

Anthropic's CLI tool that runs in a terminal session, scoped to a working directory. You describe a task; the agent reads files, writes files, runs commands.

Best at: delegated multi-step tasks. You don't want to babysit; you want to come back when it's done.

Pricing: Anthropic API usage (variable, can be higher than Cursor for heavy use).

Codex / Copilot — Autocomplete in your editor

GitHub's tab-complete AI. Suggests the next line as you type. Less about chat, more about flow.

Best at: typing-pattern completion, boilerplate, tests. The "I know what I want, just type it for me" tier.

Pricing: $10/mo individual, $19/mo business.

When to pick which

Inline edit in a file you have open

"Refactor this React component to use the new hook."

Cursor wins. Highlight the code, Cmd+K, prompt, done. Fast, in-flow, no context switch.

Claude Code would work but the round-trip is heavier; Codex isn't really designed for this.

Multi-file refactor with investigation

"Find all places that use the old auth middleware and migrate to the new path."

Claude Code wins. The task spans many files, requires the agent to investigate first. Cursor's agent mode can do this but blocks your editor while running. Claude Code runs in a terminal session — kick it off, do something else.

Single-line completion as you type

Typing function handleSubmit(e: and Codex completes the rest.

Codex / Copilot wins. Cursor's tab is similar. Claude Code is overkill for this — there's no chat, just typing.

"Something is broken, find and fix"

"The flaky test in tests/integration/auth.test.ts is failing again. Investigate."

Claude Code wins. The task starts as exploration (read the test, find what it depends on, hypothesize), becomes change. Multi-step, multi-file. Delegate.

Cursor agent mode also works but ties up the editor. Codex doesn't do investigation.

Adding a new feature

Two cases:

Short feature (1-2 files, you know the shape):

"Add a formatDate utility that takes a Date and a format string."

Cursor, in the new file, prompt + accept. Done in 2 minutes.

Long feature (5+ files, requires understanding existing patterns):

"Add an avatar upload endpoint following our existing controller/service/repo pattern."

Claude Code. Walk it through the pattern (or have it read the patterns from existing files), let it implement across files.

Reviewing a PR

"Read this PR diff. Anything concerning?"

Cursor's chat or a dedicated review tool (CodeRabbit, Greptile). Not Codex (no chat). Claude Code can do it but the flow is heavy.

Concrete decision flows

Flow 1: Bug report comes in

Severity: P0?
  → Investigate yourself first (Cursor + manual reading)
  → Once you know the shape, delegate to Claude Code or fix in Cursor

Severity: P2 (no rush)?
  → Claude Code: "investigate this bug, propose a fix"
  → Review later

Flow 2: New feature spec arrives

Spec is 1-2 functions?
  → Cursor inline as you write tests + implementation

Spec is multi-file?
  → Read existing patterns in Cursor first
  → Delegate full implementation to Claude Code with patterns referenced
  → Review the resulting branch

Flow 3: Daily flow

Morning: review yesterday's Claude Code session output (in Cursor or mq-dir's preview)
Mid-morning: write code in Cursor; small tasks via Cursor inline
Lunch: kick off a multi-step Claude Code task
Afternoon: write code; let Claude Code task continue
End of day: review what Claude Code produced; merge or iterate

What each tool gets wrong

For honesty:

Cursor

• Multi-file refactors block the editor.
• Agent mode timeouts on long tasks.
• Sometimes loses context across long sessions.
• $20/mo is the right price but Pro tier is occasionally rate-limited.

Claude Code

• High cost for heavy use (Anthropic API pricing).
• Terminal-only — non-terminal-comfortable users find it foreign.
• No inline editing — saves required before agent sees changes.
• Less integrated with editor LSP/diagnostics than Cursor.

Codex / Copilot

• Doesn't understand your codebase at the level Cursor or Claude Code do.
• Autocomplete only — not a multi-step workhorse.
• Hallucinations more frequent than top tier (better in 2026 than 2024 but still real).

What to skip

• "Replacing all three with a hand-rolled CLI wrapper": doable but not worth the maintenance.
• Local LLMs in 2026 for these workflows: still a gap vs. frontier models. Use for privacy-required tasks; expect lower quality.
• AI inside your IDE built by your IDE vendor: usually behind Cursor/Copilot. Use the established players.

File-manager setup for this multi-tool workflow

mq-dir's quad-pane is helpful here:

• Pane 1: project repo (Cursor's working dir).
• Pane 2: Claude Code session directory + artifacts.
• Pane 3: cmux pane showing Claude Code's terminal output.
• Pane 4: notes / scratchpad.

You see all three contexts at once: in-editor work (via Cursor), delegated work (via Claude Code in cmux), notes captured. No alt-tabbing.

Cost summary

For typical heavy use:

Most serious users have Cursor + Claude Code = ~$50-120/mo. Some add Copilot for the autocomplete (~$60-130/mo total).

Verdict

Three tools, three optimal niches:

• Cursor: in-editor flow tasks, short and medium.
• Claude Code: delegated multi-step, investigation, PR-shaped work.
• Codex / Copilot: type-as-you-go autocomplete.

The most common 2026 setup is Cursor + Claude Code. Pair them with mq-dir for visual orchestration, cmux for session management. Add Copilot if autocomplete matters.

Don't try to use one tool for everything. Each is optimized for a workflow shape; matching task to tool is the productivity gain.