A declared composition variable was written to the composition root as a CSS
custom property named after its own id, with no namespace. A variable called
accent therefore set --accent inline and shadowed the host theme for that
whole subtree.
That is worse than a naming clash. The accent enum values are green, blue and
violet, which are not colours, they are selectors a composition maps onto
theme slots. A representative composition maps blue to var(--accent, #18181b).
The runtime then set --accent to blue, so the lookup resolved to the CSS
keyword and no host theme could win. green and violet escaped only because
they route to --brand and --accent-2, which nothing shadowed, which is why
this survived: it was invisible for two of three values.
Variables are now written to --hf-var-<slug>. The bare name is still written
as a deprecated alias, but only for ids that are not reserved theme tokens,
which is what actually fixes the collision.
Four writers had the bug, not one: the runtime bindings, the scoped
getVariables path, the compiler stylesheet, and the SDK mutate and
apply-patches path. Fixing only the runtime left the compiler emitting the
bare name into compiled output, where a host theme supplied as an inline
style attribute still rendered the keyword. All four now route through one
helper, and the helper takes the raw id so callers cannot derive the name
themselves.
That last point closed a real defect rather than a tidy-up. Two sites derived
the property name differently, one verbatim and one slugged, so an id like
Accent produced two disjoint property sets: one path reserved it, the other
aliased it, and an SDK edit silently never landed. A test pins that every
injection path derives one name per id.
Docs that taught binding the bare name are corrected, including the capstone,
whose ink variable is reserved and would have re-skinned the ground while
quietly ignoring the ink. Rendered output is unchanged there, so the published
videos stay accurate.
- html-schema: the previous clause claimed a composition host's data-media-start is
never read. It is: readElementPlaybackStart (media.ts:16) resolves
data-playback-start ?? data-media-start and timeline.ts calls it on composition
clips. Rewrote to the accurate reason both reviewers gave — composition hosts are
only inspected by the playback-start-first readers, media-start works as a
fallback, but playback-start is what Studio writes/normalises to.
- motion test: pin the HoverVideo click-suppression (preventDefault +
stopPropagation). Removing it left the gate 12/12; now it fails. This is the bug
that escaped static review and only surfaced by driving the live preview.
- replica-compare: fold the visible 'Sound off/on' text into the aria-label so the
accessible name contains it (WCAG 2.5.3, Rames).
Round-5 findings from Magi and Rames.
- replica-compare: the offscreen teardown now resets muted (element + React state),
matching HoverVideo — a pair unmuted before it scrolled away no longer returns
reading 'Sound on' over a paused, sourceless pair (Magi blocker).
- Both controls' aria-labels now follow the mode: under reduced motion the button
plays/pauses the whole comparison, and when a preview is already autoplaying
muted the action is 'unmute', not 'play with sound' (self-review + Rames).
- Hardened the motion-suite assertion to scope 'startBoth' to toggleSound's body
(a defined-but-unused helper no longer satisfies it) and pin the offscreen
muted-reset transition (Rames mutation-test gap).
- html-schema: 'hyperframes validate' inspects <audio> only; note that no
media-start-only reader inspects a composition host, so the kind rule strands
nobody (Rames).
Per Rames: add the engine audio mixer (audioMixer.ts:350 -> ffmpeg -ss) to the
media-start-only readers — it's the live path that makes a lone data-playback-start
a shipped output bug (trimmed picture over untrimmed audio). 'Set one' isn't enough;
give the element-kind rule: <video>/<audio> use data-media-start, nested composition
uses data-playback-start (Studio writes it; it's the child-timeline offset). Also fix
editing-existing-videos.mdx, which offered both names as interchangeable for front
trim of a clip — the exact kind where they aren't.
- replica-compare: the voluntary control now starts and pauses BOTH films (not
just the reference), and the replica-sync effect attaches in view regardless of
the preference, so a reduced-motion visitor who presses play sees the whole
synchronized pair. Added a focused source-level assertion to the motion-check
suite (the repo has no React runtime harness for snippets).
- html-schema: describe each layer precisely instead of grouping the CLI —
timing compiler, HTML parser, producer audio, and 'hyperframes validate' read
only data-media-start; runtime, Studio and 'hyperframes snapshot' read
data-playback-start first (Studio also writes it).
Round-3 findings from Magi.
- edit-operations: dispatch() does not consult can() (session.ts:608 -> applyOp
with no validation; a no-timeline addGsapTween/addLabel is a no-op but a missing
target still writes via selector fallback). Use Rames's wording: call can() first
and skip on failure — no false 'applies nothing' guarantee.
- timing-and-animation: the second E_NO_GSAP_TIMELINE site — gated setGsapTween on
an error it cannot return and called shipped parser code 'a later phase'. Rewrote
to gate addGsapTween (which can return it); dropped the stale can() comment in
types.ts:595.
- html-schema: data-playback-start is read by runtime, Studio and CLI (Studio also
writes it, timelineEditingHelpers.ts); only the compile path is media-start only.
Document the layered precedence instead of calling it runtime-only.
Round-2 findings from Magi (#2/#3/#4) and Rames.
- edit-operations: E_NO_GSAP_TIMELINE is raised only by addGsapTween and addLabel
(mutate.ts:1747), not the set/remove tween ops; drop the false 'dispatch() still
applies structurally' claim (mutate.gsap.test.ts verifies zero patches); add the
requirement to the Labels section where addLabel lives.
- html-schema: data-media-start is read by parser + timing compiler + runtime;
data-playback-start is a runtime-only alias, so a lone playback-start doesn't
shift trim/split. Document the surfaces instead of claiming one universal value.
- testing-local-changes: bun unlink cleanup used a relative cd that resolves under
the video project; use an absolute checkout path.
Flagged by Magi (P1 #2/#3, P2 #7) and Rames.
**`bun unlink hyperframes` does not exist.** Bun answers "error: bun unlink
{packageName} not implemented yet" — I ran it. The command takes no package name;
it unregisters whatever directory you are standing in. The reader arrives at that
block having just been told to cd into a video project, so even the correct form
would unregister the wrong thing and leave the global link in place — which is
exactly the failure the same page's troubleshooting section then explains. The
page created the bug it diagnosed. Now `cd packages/cli && bun unlink`.
**`data-media-start` and `data-playback-start` are one value, not two features.**
The schema page gave them separate rows with different-sounding meanings, so a
reader would reasonably think they compose. Six read sites in core are all
`playbackStart ?? mediaStart` — runtime/media.ts:18 and :92, runtime/init.ts:751,
1993, 2928, 3010. One row now, alias named, and it says which wins.
**Canary rollouts contradicted itself.** Line 109 called enrolment a pure function
of `(feature, installId, percentage)`; line 195 said canaries bucket on a
dedicated `bucketSeed`, not the telemetry id. The second is right —
cli/src/telemetry/canary.ts:98 is `unitId: config.bucketSeed ?? config.anonymousId`.
Also on the Studio shortcuts page earlier: J/Shift+J for keyframe navigation,
Backspace to delete, and Ctrl+Y for redo were all missing.
Adds the pages the rebuilt navigation is organised around, and moves the sidebar
onto that structure. Every entry points at a file that exists after this commit;
nothing is rewritten or removed yet, and no redirect is claimed yet.
- Studio (13 pages) — the editor had no section of its own
- One guide per creation workflow, matching the shipped agent skills
- Section hubs: Concepts, Catalog, Developers, Deploy, Workflows, Help,
Go further, Product updates, 30 Days of HyperFrames
Pages a later commit retires drop out of the sidebar here but still exist and
still resolve, so the site stays navigable at this commit.
Incidentally fixes a link to /concepts from the Lambda migration guide that is
broken on main today — the destination did not exist.
## Summary
- replace the unsupported `data-var-*` example with the current `data-variable-values` pattern
- document that variable values are carried through but still applied manually inside the nested composition
- add matching reference notes in the data-attributes, HTML schema, core package, and CLI docs
## Verification
- `npx mintlify dev --port 3100`
- browser verification with `agent-browser` on `/concepts/compositions` and `/reference/html-schema`
- proof artifacts saved locally under `tmp/issue-416-docs/`
Major improvements across all 18 pages:
- Use Mintlify components: <Steps> for tutorials, <Tabs> for alternatives,
<CodeGroup> for multi-platform commands, <Tree> for directory structures,
<AccordionGroup> for FAQ/scannable content, <Mermaid> for diagrams
- Add filename annotations to all code blocks (e.g., ```html index.html)
- Add numbered comments inside multi-step code examples
- Show expected terminal output after CLI commands
- Add "When to use" / "When NOT to use" sections to all package pages
- Add "Next Steps" CardGroup to every page (no dead-end pages)
- Cross-link between pages at point of curiosity (not just "see also" dumps)
- Expand thin pages (engine, studio) with architecture details and examples
- Add decision guides (rendering modes, template selection)
- Use <Warning> and <Note> sparingly (max 2-3 per page)
Also adds DOCS_GUIDELINES.md at repo root with writing standards.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Miguel Ángel