Merge-field reference

Every email template is a Go text/template (or html/template when body_html is non-empty). References take the form {{ .Namespace.Field }}. The list below enumerates every namespace Vetrix declares and every leaf the engine ships canonical sample values for (used by the preview page's synthetic fixture).

Auto-injected namespaces

These are available on every render without the slug having to declare them:

`System`

Path	Sample	Kind
`System.CurrentYear`	`2026`	int
`System.ServerTimeRFC3339`	`2026-04-21T14:00:00Z`	time
`System.EmailMessageID`	`<uuid@vetrix.example>`	string

Notification-category namespaces

`Issue`

Path	Sample	Kind
`Issue.Number`	`42`	int
`Issue.Title`	`Fix pagination on issue list`	string
`Issue.State`	`open`	string
`Issue.URL`	`https://vetrix.example/acme/repo/issues/42`	string
`Issue.Excerpt`	first 4 KiB of issue body or comment	string

`Repo`

Path	Sample	Kind
`Repo.Owner`	`acme`	string
`Repo.Name`	`repo`	string
`Repo.Path`	`acme/repo`	string
`Repo.URL`	`https://vetrix.example/acme/repo`	string

`Actor`

Path	Sample	Kind
`Actor.Username`	`alice`	string
`Actor.DisplayName`	`Alice Admin`	string

`Recipient`

Path	Sample	Kind
`Recipient.Username`	`bob`	string
`Recipient.Email`	`bob@example.com`	string
`Recipient.DisplayName`	`Bob Reader`	string

`Comment` (only `issue.commented`)

Path	Sample	Kind
`Comment.Body`	`Looks good to me.`	string
`Comment.URL`	`https://vetrix.example/acme/repo/issues/42#comment-7`	string

`Mention` (only `issue.mentioned`)

Path	Sample	Kind
`Mention.Context`	`/cc @bob`	string

`Transition` (only `issue.transitioned`)

Path	Sample	Kind
`Transition.From`	`in_progress`	string
`Transition.To`	`review`	string

Slug-specific namespaces

`ResetURL` (only `password_reset`)

Path	Sample	Kind
`ResetURL`	`https://vetrix.example/reset?token=…`	string

`Server` (only `smtp_test`)

Path	Sample	Kind
`Server.Host`	`vetrix.example`	string
`Server.Version`	`1.4.0`	string

Sealed funcmap

Every template can call the following funcs. Calls to anything outside this list fail at save time with kind: "unknown_function".

upper / lower — case conversion.
default <fallback> <value> — returns fallback when value is empty or zero.
coalesce <vals...> — returns the first non-empty.
trunc <n> <s> — rune-aware truncate with ellipsis.
date <fmt> <time> — format a time via Format.
time_ago <time> — "3 minutes ago".
url_encode <s> — RFC 3986 path-segment encoding.
html_safe <s> — marks a string as pre-escaped HTML. Only available in body_html templates — a plaintext template that references html_safe fails at parse time.

Rendering rules

html/template is used when body_html is non-empty; otherwise text/template. HTML-safe contextual escaping is automatic.
missingkey=zero is set — an undefined map key returns the zero value rather than a render error. Use {{ if ... }} to guard optional sections.
The engine rejects references to undeclared namespaces at parse time (not render time) so the admin UI can surface the error inline.