Snapshot identity and sharing

This page covers how Story identifies a variant's content and how you hand a state to someone else. Each share path says how much of the state the recipient can reproduce.

Content identity

A variant has a name, but names are not stable enough for every job. You can rename :story.login-form/error to :story.auth/login-error without changing the state it renders. You can also keep the name and change the state completely.

So Story also identifies a variant by a hash of its canonical content:

Hash	Answers
plan hash	Is this the same normalized plan?
run hash	Did this run behave the same way?
snapshot identity	What should a visual-regression capture key use?

A visual-regression tool can use these to tell a rename from a real change of state. Story does not compare pixels itself; it gives the tool that does a stable key.

Local visual review

Snapshot identity is what a visual-regression tool keys its baselines on. Local visual review is a Playwright recipe that captures every :test variant under each theme mode, compares the pixels against baselines kept outside the repository, and reports which content hashes moved.

Sharing

The Share dialog exposes the common handoff paths.

Share ▸ in the toolbar opens it. Each row copies one thing to the clipboard:

Command	What it copies
Share URL	The address-bar URL, which lands a recipient on this exact view.
Copy EDN	A reg-variant form for the selected variant's current state. It registers a new variant extending the selected one, so the original stays as it is.
Screenshot	A PNG of the variant canvas.
Static build	The npm run story:build command, for producing a standalone Story site (Static builds).

Copy EDN appears only while a variant is selected. With a workspace selected instead, the Share URL shares the workspace.

Copy EDN, like save as new variant… (chapter 2) and promote run → regression variant… (chapter 4), emits a whole rf.story/reg-variant form that pastes and runs as-is in a stories namespace that requires [re-frame.story :as rf.story].

The browser address bar is already meaningful. Selecting the error state in the login-form testbed from chapter 1, where it is registered as :story.login-form/error, produces a URL like:

http://localhost:8043/?variant=story.login-form%2Ferror#/stories

The URL carries everything you can choose in the shell:

Parameter	Holds
variant	The selected variant.
workspace	The selected workspace.
mode-tab	docs or test, when the variant is not on the Canvas tab.
modes	The active toolbar modes, comma-separated.
viewport	A viewport preset id, or WxH.
background	A background preset id, or a colour.
tag-filter	The selected tags, comma-separated.
overrides	The selected variant's live Controls edits, as an EDN map.
substrate	The substrate, when it is not reagent.

Selecting things pushes a new browser history entry, so Back returns to the previous view. When a pasted URL carries overrides for args the variant no longer has, the shell drops them and says so in a banner over the canvas.

Adding embed=1 renders the canvas alone, with no toolbar, sidebar or right rail, for embedding a variant in another page:

http://localhost:8043/?variant=story.login-form%2Ferror&embed=1#/stories

Reproducibility labels

Each share path states how reproducible it is:

Label	Meaning
Fully reproducible	The recipient can land on the same state.
Partially reproducible	Some state carries, but something is omitted or approximate.
View-only	The artifact shows the state but cannot replay it.

A screenshot is view-only.

Share URL and Copy EDN are fully reproducible when every input that drives the variant survives as EDN. When one does not, the row's label drops instead of pretending, and the dialog lists why under it. A Controls edit or subscription override whose value is a function makes the row view-only. A Controls edit whose value does not survive as EDN, a network reply given as a function, a setup or script step carrying a function, and overrides the URL could not apply each make it partially reproducible. The lowest reason wins, so the label never promises more than the recipient gets.

Static builds

The Share dialog's Static build row copies npm run story:build, the script that publishes your catalogue as a standalone site. Static builds sets that script up.

Privacy boundaries

Two questions are easy to blend: can this artifact reproduce the state, and should this value leave the machine? The reproducibility labels answer the first. The second is answered where values leave your machine without you choosing each one: Story-MCP and logs redact sensitive values there.

The share URL, copied EDN, screenshot and static build carry real values, unredacted. Pressing Share or Copy is you handing over your own app's state, the same as pasting console output, so anything sensitive in the variant goes with it. Read what you share.

Troubleshooting

Symptom	Cause	Fix
A shared URL opens a different state	The recipient has different registrations, or required inputs are omitted	Share the matching catalogue/source revision and inspect reproducibility reasons.
A share is labelled partially reproducible	A value or input cannot be represented faithfully	Replace functions/opaque values with declared data where possible.
The screenshot cannot reproduce the bug	It contains pixels only	Include the variant declaration or URL and its run evidence.
An EDN copy is lost after reload	It was never saved in source	Paste the form into a loaded stories namespace.