How do I use Aide to make a multi-file change safely and review the diff before applying it?

Making multi-file changes with an AI coding agent can feel risky if you’re not fully in control of what gets written to disk. Aide is designed to keep you in the driver’s seat: you can ask it to propose changes across many files, inspect the diff, iterate, and only then apply the edits. This guide explains, step by step, how to use Aide to make a multi-file change safely and review the diff before applying it.

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Why multi-file changes need extra care

Multi-file edits are powerful but dangerous when not managed carefully:

• A small misunderstanding in your prompt can propagate across dozens of files.
• Refactors can introduce subtle regressions in code, tests, and configuration.
• Large diffs are hard to review if they’re applied automatically.

Aide’s workflow is built around three safety principles:

1. Propose, don’t immediately write – Aide can plan and preview its changes first.
2. Human-in-the-loop diff review – You see exactly what will change before committing.
3. Iterative refinement – You can adjust the plan or partial changes before applying everything.

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Core workflow: Plan, preview, then apply

At a high level, the safest way to use Aide for multi-file work is:

1. Describe the desired change
2. Ask Aide to plan and show you the affected files
3. Have Aide prepare a diff without writing to disk
4. Review and refine the diff
5. Apply the approved changes
6. Run tests and final checks

Let’s go through these steps in more detail.

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1. Describe the multi-file change clearly

The better your initial prompt, the safer the change. Provide:

• Goal: What you want to achieve (e.g., “migrate from axios to fetch in the frontend codebase”).
• Scope: Which directories / layers should be touched (e.g., src/frontend/**, not backend/).
• Constraints: Things not to change (e.g., “do not modify API contracts or public TypeScript types”).
• Acceptance criteria: How you’ll know it’s correct (e.g., “all existing tests should still pass”).

Example prompt:

I want to replace our custom logging wrapper with the new logger utility across the codebase.

• Scope: Only files under src/ that import legacyLogger.
• Change:
  • Replace import { legacyLogger } from '../utils/legacyLogger' with import logger from '../utils/logger'.
  • Replace all calls to legacyLogger.info|error|debug with logger.info|error|debug.
• Constraints:
  • Don’t touch test files in src/**/__tests__/**.
  • Don’t modify logger implementation files themselves.
• Please propose the full set of changes, show me the diff, and wait for my approval before applying anything.

This phrasing makes it clear that Aide should not write changes before you’ve seen the diff.

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2. Ask Aide to plan the change across files

Before editing, have Aide create a plan of what it intends to do and where.

Example follow-up:

First, scan the repository and list all files that will need changes for this migration.
For each file, briefly describe the planned edits.
Don’t modify any files yet — just show the plan.

Aide will typically respond with something like:

• src/app.ts – update import from legacyLogger to logger; replace 3 call sites.
• src/services/userService.ts – update import; 2 call sites.
• src/middleware/requestLogger.ts – update import; 1 call site.
• …and so on.

Use this plan to verify:

• The scope is correct (no test directories, build scripts, or unrelated areas).
• The pattern of edits matches what you described.

If anything looks off, refine your instructions before asking for a diff.

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3. Have Aide generate a diff without writing to disk

Once you’re happy with the plan, instruct Aide to prepare a diff but not apply it yet.

Example:

Great. Now generate the complete patch for these changes as a unified diff across all affected files.
Do not apply the changes yet; I only want to review the diff.

Format it as a single unified diff that I could apply with git apply.

Aide should respond with a patch like:

diff --git a/src/app.ts b/src/app.ts
index 1234567..89abcde 100644
--- a/src/app.ts
+++ b/src/app.ts
@@ -1,5 +1,5 @@
-import { legacyLogger } from '../utils/legacyLogger';
+import logger from '../utils/logger';

-legacyLogger.info('Server starting...');
+logger.info('Server starting...');

…and so on for each file.

At this point, nothing should be written to disk—you’re only working with a proposed diff.

If needed, you can ask:

Confirm that no files have been modified yet and this is only a proposed diff.

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4. Review and refine the diff

Careful review is where you keep multi-file changes safe.

4.1. Scan for scope and pattern consistency

Check:

• Are only the intended files modified?
• Are there any unrelated changes (formatting, imports, variable names) that you didn’t ask for?
• Are test files, generated files, or third-party code touched accidentally?

You can ask Aide for a summarized review:

Summarize this diff by file and type of change.
Highlight anything that looks unrelated to the logger migration.

4.2. Deep dive into critical files

For high-risk areas (e.g., authentication, payments, core business logic), ask for focused reviews:

For src/services/userService.ts, show the entire before-and-after code snippet and explain the impact of each change in detail.

If you spot problems, you have options:

• Adjust the pattern and regenerate the diff:

  Some files still use named imports from legacyLogger.
  Update your transformation rule to handle both default and named imports, then regenerate the diff.

• Exclude specific files or directories:

  Exclude src/middleware/requestLogger.ts from this change.
  Regenerate the diff without touching that file.

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5. Apply the approved changes safely

Once you’re confident in the diff, you can apply it with minimal risk. There are two common approaches depending on how Aide is integrated into your workflow.

5.1. Apply through Aide (editor-integrated)

If Aide is integrated into your editor or IDE and supports staged application:

1. Ask it to apply the reviewed diff:

   Apply exactly the diff you just showed me to the working tree.
   Do not introduce additional changes beyond that diff.

2. If the editor supports partial application, you can say:

   Apply only the changes for these files:

   • src/app.ts
   • src/services/userService.ts
     Leave the rest as-is for now.

3. After application, verify with git diff from your terminal that the on-disk changes match the patch.

5.2. Apply via git apply from the terminal

If Aide provided a raw diff in the chat:

1. Copy the diff into a file, e.g., logger-migration.patch.

2. In your terminal, run:

   git apply --stat logger-migration.patch
   

   This shows what would change, without applying it.

3. If it looks good, apply it:

   git apply logger-migration.patch
   

4. Validate with:

   git diff
   

This approach gives you maximum control: Aide only proposes the patch; git enforces it.

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6. Run tests and final verification

After the patch is applied:

1. Run your test suite:

   npm test
   # or
   pytest
   # or your project’s equivalent
   

2. Run any static checks or linters:

   npm run lint
   npm run typecheck
   

3. If there are failures, involve Aide with concrete context:

   Tests are failing after the logger migration.
   Here’s the test output and the changed file:
   [paste error + relevant diff or code snippet]
   Help me fix this without undoing the rest of the migration.

This gives Aide a tight feedback loop while keeping you in control of what ultimately lands.

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Example end-to-end interaction pattern

Below is a condensed example you can adapt whenever you need a safe multi-file change and diff review.

1. Goal + constraints:

   I want to rename the User interface to AccountUser across the TypeScript codebase.

   • Scope: src/** only.
   • Don’t modify database schema or migration files.
   • Don’t change serialized API responses, only internal types.

   Plan the changes, show the diff, and wait for my confirmation before applying anything.

2. Plan:

   First, list all files where User is an interface or type we own, not a library import.
   Show me a plan of which files you’ll modify and how.

3. Diff-only mode:

   Generate a unified diff for all of these changes.
   Do not apply anything yet; I just want to review.

4. Review and refine:

   Summarize the diff and highlight any places where User appears in public API contracts.
   For those, don’t rename the type; only update internal usage.

5. Apply:

   Apply exactly the final reviewed diff to the working tree.
   Confirm when it’s done, and don’t make any additional edits.

6. Validate:

   Tests are failing in userRoutes.test.ts.
   Here’s the failure output and the relevant new type definitions.
   Suggest a fix.

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Tips for safer multi-file changes with Aide

To make Aide even safer and more effective for multi-file edits:

• Always request a plan first for non-trivial refactors.
• Explicitly say “do not apply yet” whenever you want a diff-only step.
• Keep scopes narrow: point Aide to specific directories or file patterns.
• Iterate in chunks for very large repos (e.g., migrate one module at a time).
• Use git aggressively: branch per refactor, review with git diff, and use git restore to undo experiments.
• Favor mechanical patterns (import replacements, symbol renames) over open-ended rewrites when operating across many files.

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By following a “plan → diff → review → apply → test” workflow, you can use Aide to perform large, multi-file changes with the same confidence you’d have when writing smaller, manual edits. The key is to treat Aide as a powerful assistant that proposes patches—not an auto-committer—and to always review the diff before anything hits your repository.