How to Feed Your Codebase Context Without Pasting Everything

When an AI coding answer misses the mark, the instinct is to paste more code. Usually that makes it worse. The model needs the right context, not all of it, and a short brief beats a 3,000-line dump almost every time. You will find this brief built into most prompts in the code library.

Here is how we write a reusable context brief: a few paragraphs about the project that go at the top of every coding prompt. It is the same idea as the reusable persona, just for your codebase.

Why the full dump fails

• Important details get lost among unrelated files.
• The model starts copying patterns from old or deprecated code.
• You hit length limits and the most relevant part gets cut.

What goes into a context brief

Keep it to what a new developer would need on day one:

Project: WordPress plugin, PHP 8.0+, no Composer dependencies.
Coding standard: WordPress Coding Standards, tabs for indentation.
Architecture: one class per file in /includes, prefixed APM_.
Data: custom post types and taxonomies, no custom tables except
a usage log.
Rules:
- Escape all output (esc_html, esc_attr, esc_url).
- Every REST route has a permission_callback.
- No jQuery in new front-end code.

Add a map, not the territory

A short file tree tells the model where things live without showing every line:

includes/
  class-apm-assembler.php   builds the final prompt
  class-apm-rest.php        REST routes (apm/v1)
  class-apm-fields.php      meta registration + sanitizers
templates/
  card.php, single-prompt.php

Interfaces, not implementations

When the task touches another part of the code, include the function signatures and docblocks, not the full bodies. That’s usually enough for the model to call them correctly:

/**
 * Assemble a prompt with snippets, variables and kind details.
 *
 * @return array{text:string,missing:string[]}|WP_Error
 */
public static function assemble( int $prompt_id, array $args = array() );

Make it a habit

1. Write the brief once and store it as a reusable snippet.
2. Include it at the top of every coding prompt for that project.
3. Paste only the file you are changing, plus signatures of anything it calls.
4. Update the brief when a convention changes, not when a prompt fails.

Context is a budget. Spend it on what the model can’t guess.

From our internal prompt guidelines