# Script loading > The plugin loop's shim contract, shape guards, build pipeline, and the security rules Docsy's own plugins follow --- LLMS index: [llms.txt](/llms.txt) --- [`_partials/scripts/plugins.html`][plugins.html] implements `params.docsy.plugins`. For the configuration reference and the plugin file contract, see the [plugins guide][guide]; for the design rationale, the [design notes][design]; for the tests that pin this contract, the [quality notes][quality]. ## Loop mechanics The template's comments carry the mechanics and their rationale. The loop reads the theme's schema through `hugo.Data`; the guide [renders the same file][guide-config], so the entry contract has one home. ## Shims For when to add or replace a shim, see the guide's [Adjust a plugin per page][guide-shims]; this section is the contract. The loop resolves a shim by registry name with the schema's reserved `_docsy-shim` suffix and, when the partial exists, invokes it with `(dict "Page" PAGE "Plugin" ENTRY)`: the page being rendered, and the merged, normalized entry. The call comes after normalization and name validation, so a shim cannot reorder emission. It comes before the required-field and `version` guards, the enable check, and asset lookup, so a shim runs for a disabled entry too, and what it returns is what those two guards test. The partial must return the entry it received, adjusted with `merge` so the fields it leaves alone keep their normalized values; anything but a map fails the build. A shim is also where a plugin gates itself: on a page that doesn't need the plugin, it returns the entry with `enable` false ([Gating decisions][design-gating]). When support for a deprecated parameter ends, remove its mapping and warning from the shim and keep the rest. ## Shape guards Enforcement is hand-coded in the loop against the schema; what each guard warns about, ignores, or empties is the guide's [Warnings][guide-warnings] list. A refused `version` skips the entry. ## Build and emission The [file contract][guide-files] is the guide's; the pipeline adds one step beyond it, minification in production ([why companions first][design-ordering]). ## Security constraints Docsy's own plugins follow the guide's [rules for plugin authors][guide-security]. In addition: - Validate a configuration value against an allowlist before it reaches a fetch URL: the loop does this for every supplied entry `version`, so a companion only checks that its plugin provides a pin. - Residual exposure, disclosed in the guide's [MarkMap version][guide-markmap] section: the autoloader's runtime libraries. - Imported Hugo modules are trusted: their `params` merge into the site's, so a module can register or turn off plugins, and its layouts can shim them, as it already supplies layouts and assets. [design]: /project/design/script-loading/ [design-ordering]: /project/design/script-loading/#ordering-decisions [design-gating]: /project/design/script-loading/#gating-decisions [guide-shims]: /docs/content/plugins/#adjust-a-plugin-per-page [guide]: /docs/content/plugins/ [guide-config]: /docs/content/plugins/#configuration-reference [guide-files]: /docs/content/plugins/#plugin-files [guide-markmap]: /docs/content/diagrams-and-formulae/#markmap-version [guide-security]: /docs/content/plugins/#security [guide-warnings]: /docs/content/plugins/#warnings [plugins.html]: https://github.com/google/docsy/blob/main/theme/layouts/_partials/scripts/plugins.html [quality]: /project/quality/script-loading/