The Context

Recently, GitHub Copilot silently dropped support for Claude Opus on Pro accounts. Since Opus was my go-to model for my specific daily workflow—developing WordPress and Gravity Forms plugins—I was left looking for a reliable replacement. I decided to run a rigorous, blind benchmark across 14 state-of-the-art and local LLMs to objectively measure which model understands WordPress development best. To ensure a perfectly fair test, I always started with a completely fresh IDE and zero context for every single generation.

The Prompt (Level 1)

For this initial benchmark, I used a minimal "Level 1" prompt to see what the models would generate by default without heavy hand-holding. Here is the exact prompt I used (translated to English):

Create a WordPress plugin named GF Live Search that adds real-time search to the Gravity Forms list page (/wp-admin/?page=gf_edit_forms).

The plugin must:

• Instantly filter table rows without reloading the page
• Only load its assets on the relevant page
• Follow WordPress best practices (hooks, security, i18n)

Expected structure: gf-live-search/ ├── gf-live-search.php └── assets/ ├── gf-live-search.js └── gf-live-search.css └── languages/ ├── gf-live-search.pot

The Evaluation Process & Prompt

To establish a baseline, each generated plugin was compared against my own reference implementation (available here: https://github.com/guilamu/gf-live-search), which, while probably very perfectible itself, outlines the exact functional behavior I expected.

To avoid personal bias in the final scoring, I had Gemini 3.1 Pro act as the judge. I fed the generated code to Gemini using strictly anonymized folders (named 1, 2, 3, etc.). Here is the exact evaluation prompt I gave to Gemini 3.1 Pro to grade them (translated from French to English):

You are a code evaluator specializing in WordPress. You receive plugin implementations to evaluate.

Reference Plugin

The implementation for model X is available in directory /X. The reference implementation that the tested model had to recreate from scratch, starting from a minimal prompt, is available in the /corrigé référence directory.

Evaluation Rules

• Score on product behavior, NOT on code style or variable names.
• A naming discrepancy (e.g., noResultsRow instead of noResults) is never an error.
• A partially implemented feature receives partial points, not 0.
• If a feature is absent, the criterion score is 0.
• Do not rely on your knowledge of what the plugin "should" do: rely solely on the behavior described in the grid below.

Scoring Grid (100 pts)

1. Activation without fatal error (15 pts) The main PHP file is syntactically valid, defines the ABSPATH guard, and the plugin could activate without a fatal error. Check for: if ( ! defined( 'ABSPATH' ) ) exit;, defined constants, instantiated class.

2. Functional DOM Filtering (20 pts) The JS intercepts the native GF input (#form_list_search + input[name="s"] or equivalent), filters the <tr> rows of tbody#the-list by hiding/showing them without a page reload, and uses a debounce (any delay between 100ms and 300ms is valid).

• 20 pts: filtering + debounce + row search text caching
• 14 pts: filtering + debounce, no cache
• 8 pts: functional filtering but no debounce
• 0 pt: server-side AJAX, or jQuery form submit, or missing filter

3. Strict loading condition (10 pts) Assets are only loaded on the GF list page. Verify on the PHP side that the page is gf_edit_forms AND that we are not on a specific form editor (absence of $_GET['id'] > 0).

• 10 pts: double condition (page + absence of form id)
• 6 pts: condition on gf_edit_forms only
• 0 pt: loading on all admin pages or missing condition

4. "No results" row (10 pts) A "no results" type row is injected into the DOM and displayed only when the active filter does not match any row. It must disappear when the field is cleared.

• 10 pts: complete behavior (appears / disappears / translated or static text)
• 5 pts: present but does not disappear correctly
• 0 pt: absent

5. Keyboard shortcuts (10 pts) A keyboard shortcut focuses the search input. Ignore if the focus is already in an editable field (input, textarea, select, contenteditable).

• 10 pts: Ctrl/Cmd+F AND the / key
• 6 pts: only one of the two
• 3 pts: shortcut present but without guard on editable fields
• 0 pt: absent

6. Counter update (10 pts) The native GF counter (.displaying-num) is updated in real time to reflect the number of visible results. It is restored to its original value when the field is cleared.

• 10 pts: update + restoration
• 6 pts: update without restoration
• 0 pt: absent

7. Preloading paginated pages (10 pts) If the GF list is paginated (multiple pages), the JS loads the other pages in the background via fetch so that the filter operates on all forms, not just the current page.

• 10 pts: fetch + HTML parsing + injection of rows into the DOM
• 4 pts: pagination mechanism present but incomplete or using WP AJAX
• 0 pt: absent (filter limited to the current page only)

8. Diacritics and case (5 pts) The comparison is case-insensitive AND diacritic-insensitive (é finds e, É finds é).

• 5 pts: .toLowerCase() + .normalize('NFD') + removal of accents
• 2 pts: case-insensitive only
• 0 pt: raw comparison

9. Internationalization (5 pts) User-visible strings are translatable.

• 5 pts: __() / _n() on PHP side + mechanism to pass translations to JS (wp_add_inline_script or wp_localize_script)
• 2 pts: __() on PHP side only, JS hardcoded
• 0 pt: no i18n

10. PHP code quality (5 pts)

• 5 pts: singleton class, defined('ABSPATH'), plugin constants (DIR/URL/VERSION), admin_enqueue_scripts hook (not wp_enqueue_scripts)
• 3 pts: 3 out of 4 elements present
• 1 pt: functional procedural code but missing standard WP patterns
• 0 pt: invalid or unusable code

Expected Response Format

Return ONLY a valid JSON block, without text before or after...

The Findings

1. The "Blind Spot": Re-inventing the wheel

Out of 14 models, exactly 0 successfully hooked into the native Gravity Forms search input (#form_list_search). Instead of analyzing the DOM and integrating with the existing UI, every single model injected a brand new, redundant <input> into the page (via document.createElement, jQuery, or PHP hooks).

2. Complete lack of advanced UX foresight

Because it wasn't explicitly asked for in the initial Level 1 prompt, no model anticipated the need for keyboard shortcuts, nor did any attempt to update the native item counter as rows were hidden. Zero models implemented background-fetching (fetch()) for paginated pages to make the search global.

3. The Diacritics Separator

Most models used a simple .toLowerCase() for filtering, which breaks on accents. Only a select few (Claude 4.7 Opus, Mimo v2.5 pro) implemented robust normalization (.normalize('NFD').replace(/[\u0300-\u036f]/g, '')) to handle case and diacritics correctly.

4. Local models struggled (especially Gemma)

The local inferences failed to keep up with cloud providers. Gemma4-26b underperformed significantly, generating a fatal PHP error (calling an undefined method) and scoring 18/100. The smaller Gemma4-e4b (32/100) provided a functional but naive JS implementation with zero translations or advanced features.

5. Claude 4.7 Opus takes the top spot

Despite failing the native UI integration like the others, Claude 4.7 Opus (using a planning prompt approach) scored the highest (68/100). It wrote performant JavaScript by pre-caching DOM text in data attributes, debouncing inputs (120ms), handling diacritics properly, and utilizing modern WordPress i18n (wp_set_script_translations). It stands out as the most capable direct replacement for Copilot Pro Opus.

Price vs. Performance Observation: GLM 5.1

While Claude 4.7 Opus achieved the highest score, GLM 5.1 secured a notable 2nd place (61/100). When comparing the OpenRouter pricing for these top-performing models, GLM 5.1 offers a highly competitive price-to-performance ratio:

• GLM 5.1 (Score: 61): $1.05 / 1M input | $3.50 / 1M output
• Claude Sonnet 4.6 (Score: 55): $3.00 / 1M input | $15.00 / 1M output (~3-4x more expensive)
• Claude Opus 4.7 (Score: 68): $5.00 / 1M input | $25.00 / 1M output (~5-7x more expensive)

Delivering solid architecture (Singleton pattern, clean i18n, structured PHP) at this price point makes GLM 5.1 a very cost-effective alternative for daily automated coding tasks.

The Leaderboard

1. Claude 4.7 Opus plan – 68
2. GLM 5.1 – 61
3. Claude 4.6 Opus plan – 59
4. Mimo v2.5 pro – 58
5. Qwen 3.6+ – 55
6. Sonnet 4.6 – 55
7. Gemini 3.1 pro – 53
8. Kimi K2.6 – 49
9. GPT 5.4 xHigh – 49
10. Gemini 3 flash – 47
11. Claude 4.7 Opus fast – 46
12. Minimax m2.7 – 36
13. Gemma4-e4b (Local rx6700) – 32
14. Gemma4-26b (Local CPU) – 18

Conclusion

When given a basic prompt, even the best LLMs default to the path of least resistance: "just make it work." Rather than attempting to analyze the implicit context (the existing DOM structure), they forcefully inject new elements. If you want native-feeling, fully integrated UX, you cannot rely on the model's implicit knowledge; you have to explicitly prompt for it.

I will be testing Level 2 prompt next, feeding the models a Wordpress+Gravity Forms reference file to see how they adapt.