Short answer: Give the tool concrete context it can't guess: the exact file, the error message, an example of correct output. Ask for one change at a time, and tell it how to verify the result, run the tests, run the build, so you're not the one deciding by eye whether it actually worked. Save the context you'd otherwise repeat every session into a persistent file:
CLAUDE.mdfor Claude Code, a Cursor rule, or.github/copilot-instructions.mdfor GitHub Copilot. For a change touching more than one or two files, ask for a plan first.
Type "fix the bug" into Claude Code, Cursor, or GitHub Copilot and you'll get an answer. Whether it's the right one is a different question, kasi the tool doesn't know which bug, which file, or what "fixed" looks like unless you tell it. The gap between a prompt that gets lucky and one that gets the actual fix on the first try isn't a secret trick. It's mostly context, one task at a time, and a way for the tool to check its own work.
This is written for anyone using an AI coding tool day to day, whether you came from a bootcamp, a cohort like ours, or you're teaching yourself with Claude Code, Cursor, Copilot, or a no-code builder. The examples use real syntax from each tool's current docs, verified this week.
Why does a vague prompt get you the wrong fix?
Anthropic's own Claude Code documentation puts the core problem plainly: "Claude can infer intent, but it can't read your mind. Reference specific files, mention constraints, and point to example patterns." These tools are agentic: they read your files, run commands, and make changes on their own, so you're no longer copy-pasting code back and forth and checking each snippet by hand. That autonomy is the whole point, but it also means a vague instruction gets executed confidently in whatever direction the tool guesses. A cautious junior dev might pause and ask what you meant. An AI coding tool generally won't.
The official docs' own before-and-after examples make the pattern clear:
| Vague prompt | What's missing | Specific prompt |
|---|---|---|
| "add tests for foo.py" | which scenario, mocking preference | "write a test for foo.py covering the edge case where the user is logged out. avoid mocks." |
| "fix the login bug" | the symptom, the likely location, what "fixed" means | "users report login fails after session timeout. check the auth flow in src/auth/, especially token refresh. write a failing test that reproduces the issue, then fix it." |
| "add a calendar widget" | which existing pattern to follow | "look at how existing widgets are implemented on the home page. HotDogWidget.php is a good example. follow the pattern to implement a calendar widget that lets the user select a month and paginate by year." |
Notice none of these are longer for the sake of it. Each one just answers a question the tool would otherwise have to guess: which file, which case, which existing pattern to copy.
How much context should I actually include?
More than you'd think, but not a wall of text. A few habits that consistently help:
- Reference files directly. Claude Code and Cursor both let you type
@filenameto pull a file straight into context; GitHub Copilot Chat uses#filethe same way. The tool then reads the actual current content, which is more reliable than your memory of what's in it. - Paste the exact error. A one-line "it's broken" forces the tool to go looking for something you already know. The literal stack trace or error message tells it exactly where to start.
- Give it URLs for docs it needs. All three tools can fetch a page you link to; this matters most for a library version or API that's newer than the model's training data.
- Let it fetch what it needs itself. If you're not sure which files are relevant, tell Claude Code or Cursor to explore the codebase first and summarize what it finds, then narrow the scope from there.
One caution that cuts the other way: don't over-plan every prompt. The official Claude Code guide notes that a vague prompt like "what would you improve in this file?" is sometimes exactly right, because it surfaces things you wouldn't have thought to ask about. Specificity is for when you already know what you want. Exploration is for when you don't yet.
When should I ask for a plan before asking for code?
For anything bigger than a one-line fix, yes. Both Claude Code and Cursor have a plan mode that reads and reasons about your code without touching it, and Shift+Tab is the key for both: in Claude Code it toggles plan mode on and off directly, and in Cursor it rotates through Agent, Plan, and Ask modes until Plan is selected. In Claude Code you can also start a session already in plan mode with claude --permission-mode plan, and press Ctrl+G to open the plan in your editor and revise it directly before approving.
The recommended four-step loop, straight from Anthropic's best-practices docs:
- Explore. In plan mode, ask it to read the relevant code and explain what it finds, before any change happens.
- Plan. Ask for a concrete implementation plan: which files change, what the approach is.
- Implement. Exit plan mode and let it write the code against the plan you approved.
- Commit. Ask it to commit with a descriptive message once you've reviewed the diff.
This catches a wrong plan while it's still cheap to fix. A wrong implementation is a lot more expensive to unwind once it's already in the codebase. But the same docs are explicit that plan mode has overhead: "For tasks where the scope is clear and the fix is small (like fixing a typo, adding a log line, or renaming a variable) ask Claude to do it directly... If you could describe the diff in one sentence, skip the plan."
How do I stop repeating the same context every single prompt?
Every major AI coding tool has a file for exactly this, so your conventions, commands, and hard rules get read automatically at the start of every session. You write them once:
| Tool | File | Format | How it's scoped |
|---|---|---|---|
| Claude Code | CLAUDE.md (or AGENTS.md) | Plain markdown | Project root, user-level (~/.claude/CLAUDE.md), or nested in subdirectories |
| Cursor | .cursor/rules/*.mdc | Markdown with YAML frontmatter (description, globs, alwaysApply) | Per-rule: always-on, auto-attached to matching file paths, or manually invoked |
| GitHub Copilot | .github/copilot-instructions.md | Plain markdown | Repository-wide; Copilot lists the file under "References" in its response when it's used |
Worth knowing: Claude Code can now read a repository's existing AGENTS.md directly as of version 2.1.277, so a project already set up for another coding agent doesn't need a separate CLAUDE.md. The default rule is simple: if your working directory (or any directory above it) has a CLAUDE.md, Claude reads that instead; only when there's no CLAUDE.md does it fall back to AGENTS.md. If you want a single shared file read by both, you add a one-line @AGENTS.md import inside a CLAUDE.md, which is exactly what this site's own repository does.
AGENTS.md itself is becoming the closest thing to a universal standard here. It was created in 2025 by OpenAI, Google, Cursor, and others specifically so one plain markdown file could work across different AI coding agents, and in December 2025 the Linux Foundation's newly formed Agentic AI Foundation took it on as one of its three founding projects, alongside MCP and the Goose agent. OpenAI, which contributed the project, says it's been adopted by more than 60,000 open-source projects and agent frameworks as of the foundation's December 2025 launch, though that figure comes from the company itself and hasn't been independently audited.
For Cursor specifically, know that the single root .cursorrules file still works but is deprecated in favor of the newer .cursor/rules/ directory, where each rule lives in its own .mdc file scoped to specific file paths, so it only loads for the prompts where it's actually relevant.
How do I get a bug fixed on the first try?
Use the same structure you'd use reporting a bug to a human teammate: what you expected, what actually happened, and the exact error. Compare:
Bad: "the build is failing, pls fix"
Good: "the build fails with this error: [paste the exact error].
It started after I added the new auth middleware in src/middleware/auth.ts.
Fix the root cause, don't just suppress the error."
That last line matters more than it looks. AI coding tools can "fix" a failing build by wrapping the error in a try/catch or disabling a check, which makes the symptom disappear without fixing anything. Naming the root cause as a requirement up front heads that off before it happens. Catching the same shortcut in code review later costs real time.
GitHub's own prompt-writing guidance for Copilot makes a related point, using a recipe analogy: break a complex task into discrete steps and let Copilot generate code after each one, checking the result before moving to the next. A single paragraph describing the whole dish leaves too much to guesswork.
How do I make sure the AI actually checked its work?
Ask it to, explicitly, and ask it to show you proof: the test output, the command it ran, the actual result. Anthropic's best-practices guide frames this directly: "Claude stops when the work looks done. Without a check it can run, 'looks done' is the only signal available, and you become the verification loop: every mistake waits for you to notice it." Give it something with a pass-or-fail answer, a test suite, a build, a screenshot compared against a design, and have it keep iterating until that check actually passes. Code that merely compiles hasn't cleared that bar yet.
In practice that's as simple as ending your prompt with "run the tests after" or "take a screenshot of the result and compare it to the design I pasted." For anything you're not going to sit and watch, that one line is the difference between code that was checked and code that was assumed to work. Reading the test output it already ran also saves you the trouble of re-running the check yourself, and it works even for a session you stepped away from.
Frequently asked questions
Do I need to learn formal "prompt engineering" to use these tools well?
No special syntax or framework is required for day-to-day coding work. What actually moves the needle is the same information you'd give a new teammate on day one: which file, what the constraint is, what "done" looks like, and how to check it. Treat the tool like a capable but new collaborator who needs a real brief, the way you'd onboard an actual new hire.
Should I write one big prompt describing the whole feature, or break it into steps?
Break it into steps for anything beyond a small, well-understood change. Asking for ten features in one prompt makes it harder to verify any single piece, and a mistake early in the output tends to compound through everything after it. A clear plan followed by implementation in stages, as covered above, catches a wrong direction while it's still one step to undo.
What if it keeps making the same mistake even after I correct it?
That's usually a sign the conversation itself is the problem. Claude Code's own guidance is to start fresh (/clear) after two failed corrections on the same issue, then write one better prompt that incorporates what you just learned. A third correction on top of an already-cluttered context rarely does better than that clean restart would.
Is there one file format that works across every AI coding tool?
AGENTS.md is the closest thing, and it's now backed by Anthropic, OpenAI, and others through the Linux Foundation. But support still varies by tool and version: Claude Code only reads it automatically when there's no CLAUDE.md present, and other tools have their own precedence rules. Check each tool's current docs before assuming a shared file is actually being read. It may just be sitting there, quietly ignored.
Does any of this apply if I'm using a no-code tool like Lovable or v0 instead of Claude Code?
Yes, the underlying principles don't change even without a terminal or a visible diff. Naming the exact screen, the exact constraint ("keep the existing color scheme"), and what correct looks like still produces a better first result than "make it nicer." What changes is mainly the verification step: there's no test suite to run, so you check the rendered preview against what you actually asked for.
Our free Ship Your First Project challenge walks through exactly this loop, prompt, build, verify, on a real app over seven days, whichever tool you're using.
Sources
- Best practices for Claude Code, Claude Code Docs
- How Claude remembers your project, Claude Code Docs
- Adding repository custom instructions for GitHub Copilot, GitHub Docs
- How to write better prompts for GitHub Copilot, The GitHub Blog
- Cursor Rules, Cursor Docs
- Plan Mode, Cursor Blog
- The Linux Foundation Announces Formation of the Agentic AI Foundation, Privacy Guides, December 2025
- OpenAI, Anthropic, Block launch Agentic AI Foundation under Linux Foundation, YourStory, December 2025