Cairn Documentation
Editing Interfaces
v1.1.0-beta makes interfaces fully editable. Where earlier versions limited you to AI-driven creation and tweaks via re-prompting, every field on every interface — and every signal — is now click-to-edit in the Inspector. This page covers the editing surfaces; for what an interface conceptually represents, see Interfaces & Signals.
Editing Existing Interfaces
Open an interface in the Inspector — click its edge in the Architecture lens, or click an interface row in the Overview lens's Interfaces section. The fields are:
- Name — short label shown on the canvas edge
- Description — multi-line explanation of what crosses this boundary
- Protocol — autocomplete picker (CAN bus, Ethernet, USB, custom strings allowed)
- Source and Target — the two endpoint nodes
Click a field, type the new value, and press Enter (or click outside) to commit. Source and target reject same-source-as-target — an interface always connects two distinct nodes.
Working with Signals
Signals appear as a list inside the interface Inspector. Each row collapses by default to its name and direction; click the chevron to expand the full editing grid: data type, direction, rate, and the simulation-relevant metadata (bandwidth, latency, range, reliability).
Add a signal with the + New Signal button at the foot of the list. Remove with the row's Remove button — which arms first and asks for a second click within three seconds, so a stray click won't take a signal with it.
Units on the metadata fields are free-text for now. Future releases will cross-reference the project's unit catalog; until then, type the unit you mean (ms, Mbps, %, and so on).
Creating an Interface Manually
Two surfaces let you create an interface by hand instead of through ⌘K:
From the Architecture canvas — right-click a node and choose Connect to… (manual). A small form opens; pick the target node, type a name, optionally fill the protocol and description, and submit. The interface appears on the canvas immediately.
From an open interface's Inspector — when you have an interface selected, the Inspector exposes a + New Interface button next to the title. It opens the same form with no pre-fills; pick the source and target yourself.
Both forms reject same-source-as-target submissions and require the name field to be non-empty.
Deleting Interfaces
Use the Inspector's Delete button. The cascade preview lists every trace link that points to the interface and any signal rows that would go with it, so you can see the impact before you confirm. Cancel to leave everything in place.
How This Fits with AI
The Interfaces specialist still creates and modifies interfaces from natural-language prompts — that flow hasn't changed. AI changes route through ChangeSet review (see AI Pipeline); manual edits commit immediately. The two paths produce the same model and can be used interchangeably on the same interface — edit a name by hand after the AI created it, or ask the AI to redesign an interface you started manually. See Manual and AI Pathsfor the broader framing.