System Information

Use this skill when a problem might depend on the environment or the installed dependency versions rather than the code: a missing or misconfigured extension, behavior that only reproduces on a specific PHP/OS version, or a bug that looks like a version mismatch — a method, argument, or class that does not exist in the release that is actually installed.

Capabilities

server-info reports the runtime only — it does not return package versions. Use Composer for those.

Runtime checks

1. Start with the server-info tool for PHP version, OS, OS family, and loaded extensions — prefer it over php -v, php -m, or uname.
2. Confirm a required extension is loaded before blaming the code. If it is absent from server-info, the fix is an environment/configuration change, not a code change.

Resolving package versions

composer.json declares constraints (what is allowed); composer.lock records what is actually installed. For "what is really running", trust the lock, not the constraint.

• One package: composer show symfony/console → installed version plus details.
• A family: composer show 'symfony/ai-*' → every matching package and its version.
• Machine-readable: composer show --format=json symfony/console.
• No Composer binary, or you want the raw record: look the package up by name under packages in composer.lock and read its version field — do not load the whole lock file into context.

Monorepo / path-repo note: locally linked packages (for example symlinked symfony/ai-* in this repository) report dev-main or a path reference instead of a semver tag — that is the working copy, not a released version.

Diagnosing a version mismatch

1. Identify the package behind the failing API — the namespace usually maps to it (Symfony\Component\Console\… → symfony/console).
2. Read the installed version with composer show <package> (or from composer.lock).
3. Compare it against the version the code expects: a method or argument added in a newer minor, or removed/renamed in a newer major, is the classic signature.
4. Report the gap precisely — name the package, the installed version, and the required one: "symfony/console is 6.4 (installed), but the code calls a 7.1 API."

Rules

• Reach for server-info and composer show first; they are cheaper and more structured than reading composer.lock or php -m wholesale.
• Report only the one or two facts that change the diagnosis (e.g. "ext-intl is not loaded", "symfony/console is 6.4, the code uses a 7.1 API") — never the full extension dump or the entire lock file.
• Never run state-changing commands. composer show is read-only; composer require, composer update, and composer install are not. This skill is read-only inspection.