Performance contract

Meaning of instant

Instant means same-frame feedback with no visible intermediate loading state. Physics prevents literal zero duration. Architecture must remove asynchronous dependencies from interaction paths.

Budgets

Reference hardware will be fixed before implementation benchmarks begin.

Interaction	Target
Note selection feedback	Same event task; no async boundary
Cached editor-state swap	P95 below 8 ms; max below 16.67 ms
Command palette open	P95 below 8 ms
Tree create, move, reorder	P95 below 8 ms
Keystroke to paint	P95 below 8 ms; max below 16.67 ms
Diagram node drag frame	Max below 16.67 ms
Main-thread task during navigation	None above 8 ms
Dropped frames during 100 cached note switches	Zero on reference hardware

Hard invariants

• No IPC during note navigation.
• No database read during note navigation.
• No Markdown parse during note navigation.
• No Git operation during editing or navigation.
• No route or editor chunk loading after startup.
• No editor component remount during note navigation.
• No post-startup skeleton for cached workspace content.
• No application-shell render from editor keystrokes.
• No broad store subscription where a selector can express the dependency.
• No production React Scan or profiling instrumentation.
• Each visible editor retains at most 32 clean note states. Active, dirty, or in-flight note states may temporarily exceed that ceiling and must never be evicted.
• Diagram pointer movement stays renderer-local, routes only incident connectors, and produces one document transaction when the gesture ends.
• Cached note navigation does not parse diagram source or run automatic layout.

Fixtures

• 1,000 and 5,000-note workspaces.
• 50, 500, and 2,000-block documents.
• 100 rapid note switches by keyboard.
• 10,000 command-palette entries.
• Continuous typing while search and history projections update.
• At least 100 distinct note visits followed by a cold revisit, with working-set size and reconstruction timing recorded.
• Mixed prose with 10-, 50-, and 150-node editable flowcharts.

Enforcement

Performance marks surround selection dispatch, editor-state installation, command opening, keystroke handling, and next paint. Long Animation Frame observations capture blocking work. React profiling records commits and affected component names. React Scan exposes avoidable renders during development but is not treated as proof of performance.

The benchmark harness runs a production build on fixed reference hardware. It stores raw samples, P50, P95, P99, maximum duration, dropped frames, long tasks, React commit counts, and editor-host mount counts. CI uses a stable dedicated performance runner; ordinary shared CI runs functional checks without pretending timing is deterministic.

Architecture changes failing budgets do not merge without an explicit ADR and a replacement measurement.

Render invariants

Interaction	Allowed React work
Editor keystroke	Editor-owned view only
Diagram drag	Diagram NodeView only; one editor transaction at gesture end
Note selection	Selected-note consumers only; editor host stays mounted
Tree selection	Previous row, next row, and direct selection consumers
Metadata edit	Changed field consumers only
Command palette query	Palette result surface only

Component counts are finalized after the UI decomposition exists. Any component rendering identical output is a regression regardless of whether the frame budget still passes.