Claude Code Plugins

Community-maintained marketplace

Feedback

preview

@Technikhighknee/agent-workbench
0
0

See what breaks BEFORE you edit. Type errors, affected callers, required tests.

Install Skill

1Download skill
2Enable skills in Claude

Open claude.ai/settings/capabilities and find the "Skills" section

3Upload to Claude

Click "Upload skill" and select the downloaded ZIP file

Note: Please verify skill by going through its instructions before using it.

SKILL.md

name preview
description See what breaks BEFORE you edit. Type errors, affected callers, required tests.
allowed-tools mcp__preview__preview_edit

preview

Know the consequences of your changes before you make them. The ultimate safety net.

The Problem

You're about to change a function. Will it break types? Who calls it? What tests need to run?

Without preview:

  1. Make the change
  2. Run type checker - find errors
  3. Fix errors
  4. Run tests - more failures
  5. Fix those too
  6. Repeat...

With preview - know all this BEFORE you edit.

First: preview_edit

preview_edit({
  file: 'src/api.ts',
  edit_type: 'symbol',
  symbol: 'fetchUser',
  new_content: 'async function fetchUser(id: string, options?: RequestOptions): Promise<User> { ... }'
})

Returns:

  • Type errors - Will this break the build?
  • Affected callers - Who calls this function?
  • Related tests - What tests should you run?
  • Impact summary - How risky is this change?

Edit Types

edit_type Required Description
symbol symbol, new_content Replace by symbol name
text old_text, new_content Text replacement
create new_content Create new file
delete - Delete file

Why This Wins

Without preview With preview
Edit → type errors → fix → more errors See all errors before editing
"Who calls this?" → search → maybe miss some All callers shown upfront
"What tests?" → guess → run wrong ones Tests discovered automatically
Risky refactoring → hope it works Know exactly what breaks

When to Use

Before Risky Changes

// Changing a widely-used function? Preview first.
preview_edit({
  file: 'src/core/utils.ts',
  edit_type: 'symbol',
  symbol: 'formatDate',
  new_content: '...',
  check_types: true,
  analyze_callers: true
})

Before Signature Changes

// Adding a required parameter? See who breaks.
preview_edit({
  file: 'src/api.ts',
  edit_type: 'symbol',
  symbol: 'createUser',
  new_content: 'async function createUser(data: UserData, options: CreateOptions) { ... }'
})

Before Refactoring

// Want to simplify a function? Know the impact.
preview_edit({
  file: 'src/handlers.ts',
  edit_type: 'symbol',
  symbol: 'processRequest',
  new_content: '...',
  find_tests: true
})

What You Get

Type Errors (Predicted)

- src/routes.ts:45 - Argument of type '{}' is not assignable to parameter 'options'
- src/handlers.ts:23 - Property 'timeout' is missing in type 'RequestOptions'

Affected Callers

- handleLogin (src/auth.ts:34) - uses fetchUser
- getUserProfile (src/profile.ts:12) - uses fetchUser
- testUserFetch (tests/api.test.ts:45) - uses fetchUser

Related Tests

- tests/api.test.ts (high confidence - naming convention)
- tests/integration/user.test.ts (high confidence - imports source)

Options

Option Default Description
check_types true Run TypeScript type checking
analyze_callers true Find all code that calls this symbol
find_tests true Discover related test files

The Workflow

  1. Think - "I want to change this function"
  2. Preview - preview_edit({ ... }) - see consequences
  3. Decide - Is this change safe? What needs updating?
  4. Edit - Make the change with confidence
  5. Verify - Run the tests you now know to run

Integration

Use with other tools:

  • After preview → syntax.edit_symbol to make the change
  • After preview → test-runner.run_related_tests to verify
  • After preview → types.check_file to confirm no errors

Not a Replacement

Preview shows you consequences. You still need to:

  • syntax.edit_symbol - actually make the change
  • types.check_file - verify after editing
  • test-runner.run_tests - run the tests

Preview is your pre-flight check. The other tools are the flight.