Developers

OpenTrust has a deliberately small filter surface and a fairly rich programmatic API. Most extension scenarios are covered by one of:

A filter on the bundled catalogs (subprocessors, certifications, data practices, FAQs).
A read against the public Repository API.
A direct call against the chat REST endpoint.

Where to look

Hooks

Every plugin-defined filter, plus the catalog-extension recipe.

REST API

POST /wp-json/opentrust/v1/chat. Request, four-gate auth, SSE protocol, error codes.

Post types & meta

Five CPTs and every _ot_* postmeta key, by content type.

Programmatic API

Repository, Version, Catalog, Secrets, Budget, Log, IO public methods.

Conventions

Class prefix: every OpenTrust class is named OpenTrust_ or OpenTrust\…. There's no autoloader; the main plugin file requires each class explicitly.
Hook prefix: every plugin-defined hook is named opentrust_*.
Postmeta prefix: every CPT meta key is named _ot_*. The leading underscore keeps them out of WordPress's default custom-fields meta box.
No global helper functions. Public APIs are static methods on OpenTrust_* classes.
All output escaped (esc_html, esc_attr, esc_url, wp_kses_post). All input sanitized.
All admin actions: manage_options capability check + _wpnonce verification.

OpenTrust does not have a theme template-override mechanism. Templates live in templates/ and are loaded with hard require / include paths. The "complete theme isolation" rendering strategy depends on these templates running unmodified.

If you need to fork rendering, fork the plugin. Do not file PRs adding locate_template() indirection: it regresses the theme-isolation guarantee.

The block content of policies still runs through apply_filters('the_content', ...), so any global content filter you have applies to policy bodies. That's the only sanctioned hook into the rendered output.

Constants

OpenTrust defines a handful of runtime constants in the main plugin file. None are user-overridable.

Plugin constants

Constant	Value	Purpose
`OPENTRUST_VERSION`	Plugin version string (e.g. `1.0.0`)	Used by asset cache-busting and import compatibility checks.
`OPENTRUST_DB_VERSION`	Integer schema version (currently `2`)	Compared against the stored `opentrust_db_version` option on every `init`.
`OPENTRUST_PLUGIN_DIR`	`plugin_dir_path(__FILE__)`	Absolute filesystem path to the plugin root.
`OPENTRUST_PLUGIN_URL`	`plugin_dir_url(__FILE__)`	Public URL of the plugin root.
`OPENTRUST_PLUGIN_FILE`	`__FILE__` of `opentrust.php`	For `register_activation_hook` and friends.

Class constants worth knowing

These are stable across the v1.x line. Code that depends on them should still pin to a plugin version.

Constant	Value	Purpose
`OpenTrust::DEFAULT_ENDPOINT_SLUG`	`'trust-center'`	Falls back here if the user clears the slug field.
`OpenTrust_Chat::REST_NAMESPACE`	`'opentrust/v1'`	REST route namespace.
`OpenTrust_Chat::REST_ROUTE`	`'/chat'`	REST route path.
`OpenTrust_Chat::MAX_TOOL_TURNS`	`8`	Cap on retrieval tool calls per visitor message.
`OpenTrust_Chat::DEFAULT_MAX_MESSAGE_LENGTH`	`1000`	Visitor message char cap (clamped to 100-4000 in settings).
`OpenTrust_Chat_Corpus::TTL`	`12 * HOUR_IN_SECONDS`	Per-locale corpus transient lifetime.
`OpenTrust_Chat_Corpus::MAX_INDEX_TOKENS`	`4000`	Soft cap on slim-index size.
`OpenTrust_Chat_Log::CRON_HOOK`	`'opentrust_chat_log_purge'`	Daily purge cron name.
`OpenTrust_Chat_Log::RETENTION_DAYS`	`90`	Log row retention before purge.
`OpenTrust_IO::SCHEMA_VERSION`	Integer schema version of the IO archive format	Imports across mismatching schemas hard-reject.

Versioning

Public APIs (catalog filters, REST endpoint, post-type slugs, postmeta keys, the documented static methods on OpenTrust_Repository and friends) follow semver. Breaking changes only in major versions. Internal helpers may change between minor versions; if you depend on something not listed in Programmatic API, pin to a plugin version.

Where to file issues

github.com/nolderoos/opentrust/issues. Include WordPress and PHP versions, OpenTrust version, whether AI chat is enabled, and any conflicting plugins.