Custom forms + computed fields

Model

ticket_categories → ticket_forms → ticket_form_fields → custom_field_defs, all scoped to a project.

• A field def is project-local by default, with a tag-prefixed slug (hr-username) and a collision guard. Soft-archive, never hard delete. Flags: sensitive (encrypted at rest, revealed to composing agents), agent_only (hidden from submitters), computed.
• A form binds fields with a per-form required flag, so a field is mandatory only on the forms that opt in. Forms carry a default title / description that pre-fill new tickets. PUT /forms/:id/fields skips invalid / archived / out-of-scope defs and returns {saved, skipped}.
• A category can set a default form, auto-selected on new ticket (a sole form auto-selects too).
• tickets.form_id records which form created the ticket. Values live in custom_field_values (ticket_id, value_text, value_text_enc).

Field types: text, textarea, number, date, select, multiselect (JSON-array values; checkbox group on the form and the card; options-validated; joined display), computed.

Agent-only fields

Hidden from the submitter’s new-ticket form. Handlers fill them on the ticket’s right-hand Custom Fields card, per-field or save-all, via PATCH /api/tickets/:id/custom-fields.

{field.<slug>} tags

Resolve in canned responses and vendor email templates (hyphen-tolerant; sensitive values revealed for the composing agent; HTML-escaped in HTML templates; sample value in preview). Both editors insert tags at the caret and expose a project-scoped Custom fields chip group. Multiselect joins values.

Deep-linkable new-ticket URLs

/tickets/new/<project-prefix>/<category-slug>/<form-slug>?<field-slug>=<value>&<multi-slug>=1,3

Segments resolve left-to-right; selects pre-fill by 1-based option number. Admin → Forms has a shareable-link builder with editable category / form slugs and optional per-field prefills.

Computed fields

A computed field derives its value from a formula over the ticket context. Computed defs are always agent_only, stored as text, excluded from create validation and manual patch.

Inputs: {field.<slug>} (form inputs), {ticket.*}, {submitter.*}, {assignee.*}, {actor.*}.

Functions: slice left right upper lower cap pad trim len digits replace match concat default if datepart. ~ concatenates. Arithmetic and comparisons. No eval, no Function, no global access — services/formula.js is a tokenizer, recursive-descent parser, and tree-walk evaluator.

# AD / M365 UPN from first initial + last name
lower(left({field.hr-first-name}, 1) ~ {field.hr-last-name}) ~ "@" ~ {field.hr-domain}

# Initial password: capitalized last name + 4 digits of the start date
cap({field.hr-last-name}) ~ datepart({field.hr-start-date}, "MMdd") ~ "!"

Evaluation: automatically on ticket create (post-commit, best-effort) and on demand via POST /api/tickets/:id/recompute-fields. POST /api/custom-fields/formula-preview dry-runs a formula against sample context. The Custom Fields card shows a Derived (auto) section, read-only, with a recompute button.

Admin

• Admin → Forms / Fields — categories, forms, field defs, the formula editor with cursor-insert tag chips and an inline demo preview, the shareable-link builder.
• Admin → Assets / Fields — custom fields for assets and consumables (defs only for consumables in this release).

Endpoints

GET/POST/PATCH    /api/custom-fields                    — defs (?project_id= ?entity_type=)
POST              /api/custom-fields/formula-preview
GET/POST/PATCH    /api/ticket-categories
GET/POST/PATCH    /api/forms
PUT               /api/forms/:id/fields
PATCH             /api/tickets/:id/custom-fields
POST              /api/tickets/:id/recompute-fields