Symfony Runtime

An AI Mate extension that exposes runtime data from the Symfony profiler to AI agents (Claude Code, Cursor, …). Where code intelligence looks at what sits on disk, this looks at what actually happens: request timing, Doctrine queries, N+1 patterns and query plans.

This is the successor to the standalone Node MCP server symfony-runtime-mcp: the same analysis tools, but now in-process as a Mate extension. That eliminates docker exec, a copied extractor script and host↔container path mapping — the tools run where the code and the database live.

For local dev environments only. Never point this at production.

Tools

Tool	What it does
slow_queries	Slowest query shapes over the last N requests, with total time, execution count and origin (file:line + source code)
detect_n_plus_one	Repeated identical queries within a single request, with the likely parent query (1+N)
request_breakdown	Wall clock of a single request broken down per category (DB / external HTTP / rendering / listeners …)
profile_diff	Before/after comparison of the same endpoint: duration, memory, query count and disappeared/appeared query shapes
explain_query	Runs EXPLAIN and tells you why a query is slow (full scan, unused index, filesort). analyze=true for SELECT/WITH only

Complementary to the official symfony/ai-symfony-mate-extension (which exposes raw profiler and container data): install both side by side.

Installation

composer require --dev skrepr/ai-performance-mate-extension

Already running AI Mate in your project (a mate/ directory exists)? Then you are done: the Mate composer plugin runs mate discover automatically after every composer require/update.

No AI Mate yet? The package pulls in symfony/ai-mate automatically; initialize it once:

vendor/bin/mate init          # creates mate/ + mcp.json (Claude Code and friends pick those up automatically)
vendor/bin/mate discover      # registers the extension; happens automatically from then on

The four profiler tools work right away: they read var/cache/dev/profiler. Make a few requests to your app and call request_breakdown, for example. Check with vendor/bin/mate mcp:tools:list that the tools are registered.

Configuration

All configuration is optional and goes through mate/config.php in your project.

explain_query — database connection

The extension does not know your app connection (Mate does not boot the kernel), so explain_query builds its own connection from a DSN. By default it falls back to DATABASE_URL from the environment; load that by setting mate.env_file:

// mate/config.php
return static function (ContainerConfigurator $container): void {
    $container->parameters()
        ->set('mate.env_file', '.env')   // loads .env and .env.local
    ;
};

mate.env_file expects a string (not an array) and requires symfony/dotenv in your project — already present in a standard Symfony app.

Using a different env var or multiple connections? Point at the DSN explicitly:

$container->parameters()
    ->set('mate.env_file', '.env')
    ->set('skrepr_mate.database_url', '%env(resolve:POSTCODE_DB_URL)%')
;

Query origins (strongly recommended)

Without backtraces, slow_queries/detect_n_plus_one know that a query is slow, but not where it comes from. Set in config/packages/dev/doctrine.yaml:

doctrine:
    dbal:
        profiling_collect_backtrace: true

With that, origin points to the exact file:line in your project code, including the surrounding source.

Custom profiler location

$container->parameters()
    ->set('skrepr_mate.profiler_dir', '%mate.root_dir%/var/cache/dev/profiler')
;

Known limitation: the Symfony bridge on PHP < 8.4

If you also use symfony/ai-symfony-mate-extension, its symfony-profiler-* tools fail on PHP < 8.4 with "Cannot generate lazy proxy": the collector formatters are final and ->lazy(), and before PHP 8.4 Symfony creates a lazy proxy through subclassing. On PHP 8.4+ this does not apply. Workaround without patching the vendor — redefine the formatters non-lazy in mate/config.php:

foreach (['Request','Exception','Mailer','Translation','Doctrine','Time','Logger','Memory'] as $name) {
    $fqcn = "Symfony\\AI\\Mate\\Bridge\\Symfony\\Profiler\\Service\\Formatter\\{$name}CollectorFormatter";
    $container->services()->set($fqcn)->tag('ai_mate.profiler_collector_formatter');
}

Requirements

• PHP ≥ 8.2
• Symfony 6.4 / 7.x / 8.x with the profiler enabled in dev (symfony/web-profiler-bundle)
• Doctrine DBAL 3.6+ / 4.x

License

MIT