A flat reference of project-specific terms used in code and docs. For deeper context, follow the cross-links into the topic-specific docs.
ABSOLUTE_TOKEN — Sentinel ThoughtId ('__ABSOLUTE__') for the absolute root, the parallel root used for the absolute context view. See constants.ts.
absolute context — A second root context whose ordering reflects recency rather than the home tree. state.absoluteContextTime is the timestamp captured when the absolute context was last entered; it shifts visibility for newly added thoughts so they surface in the absolute view. See childrenFilterPredicate in getChildren.ts.
accessToken — Per-device 21-char nanoid stored in localStorage. The device's secret: clientId (and from it the replicaId) is derived from it, and it keys the device's entry in permissionsStore. Override with ?auth=<token>. See persistence.md → Identity & sharing.
action — A Redux state-mutating function under /src/actions. Reducers are preferred over thunks; thunks only when a side effect is needed. Compose with util/reducerFlow.
agent session — One execution of a Copilot cloud agent: an ephemeral, isolated environment with its own workspace, prompt, model, and history, destroyed when it ends. A pair of copilot_work_started / copilot_work_finished timeline events brackets one, and an agent task can run several — a follow-up prompt on the pull request starts another. This is the sense the automations use for the agent working: pr-ready.yml reads the newest of those two events to tell work in progress from work that finished, and copilot-setup-steps.yml builds the environment one wakes up in. Distinct from session lock, and from a local Claude Code or Codex session.
agent task — The work item handed to a Copilot cloud agent, created by POST /agents/repos/{owner}/{repo}/tasks — the agent tasks API. The task is the durable parent: its REST representation carries a session_count and a sessions array, so one task holds one or more agent sessions. This is the sense the automations count and cap: Dependabot Fix and Copilot pull-request conflicts each start one task per dispatch, cap the tasks per pull request, and number them in their sticky comment via task-comment.cjs.
archived — Soft-deletion timestamp on Thought. Distinct from =archive, the meta-attribute parent under which archived thoughts are nested.
attribute / meta-attribute — A child thought whose value starts with = (e.g. =pin, =style, =view). Meta-attributes change app behaviour for their parent (or, with =children/=grandchildren, for descendants). Stored under their value in childrenMap for O(1) lookup. See metaprogramming.md.
attribute-child index — em_attribute_children, an app-owned SQLite table mapping each =attribute child to its parent and value. It restores the value-keying half of childrenMap, which TreeCRDT itself does not store. Rebuilt from the tree when its version changes, then maintained on every write. See persistence.md → Derived tables.
autocrop — Vertical: hides the empty space above a deep cursor by translating the layout container upward and counter-scrolling to keep visible thoughts stable. Horizontal: see indent. See layout-rendering.md → useAutocrop.
autofocus — Per-thought visibility classification (show | dim | hide | hide-parent) computed from depth relative to the cursor. The closer to the cursor, the more visible. =focus/Zoom overrides this by hiding everything outside the zoomed thought's subtree. See Autofocus.ts and calculateAutofocus.ts.
backend (drag) — react-dnd backend selected by isTouch: TouchBackend on touch, HTML5Backend on desktop. Both patched. See drag-and-drop.md → Backend selection.
belowCursor — Flag set on every TreeThought after the cursor is encountered during the in-order walk. Used to exclude hidden thoughts below the cursor from totalHeight so the document doesn't have a giant trailing dead zone.
Brand — Nominal-typing trick: Path & Brand<'SimplePath'> requires an explicit cast to convert. Used to enforce invariants TypeScript can't track. See Brand.ts.
buffer depth — BUFFER_DEPTH = 2 in pull. Beyond this depth, descendants returned by fetchDescendants are marked pending: true rather than being fully fetched. The hard BFS-queue cap is MAX_THOUGHTS_QUEUED = 100. See persistence.md → fetchDescendants.
caret — The native browser selection (window.getSelection()), typically collapsed to a vertical bar. Distinct from cursor. Direct access is gated through device/selection.ts (lint-enforced). See cursor-and-caret.md.
childrenMap — Thought.childrenMap: Index<ThoughtId>. Keyed by ThoughtId for regular children but keyed by value for meta-attributes (e.g. '=pin'). The dual keying gives meta-attribute lookups a constant-time fast path.
cliff — A drop in visible depth between consecutive thoughts. cliff = next.depth - node.depth when negative; cliff = -3 means three levels shallower. Drives extra padding (cliffPadding) and the number of DropEnd zones rendered. See DropCliff.tsx and layout-rendering.md → usePositionedThoughts.
clientId — Public key of the writer, derived as base64(SHA-256(accessToken)). Stamped on every Thought/Lexeme write as updatedBy. Available asynchronously via the clientIdReady promise. See persistence.md → Identity & sharing.
command — A user-triggered operation (keyboard shortcut, gesture, toolbar button, or Command Universe entry). Single-file definition under /src/commands implementing the Command interface; auto-registered via the barrel import in commands.ts. The legacy name shortcut still appears in some places. See commands.md.
Command Universe — Searchable list of all commands, opened with Command/Ctrl + P on desktop.
Context — string[] — a sequence of thought values from root to leaf, e.g. ['Animals', 'Cats']. Ambiguous when duplicate values exist at the same level. Prefer ThoughtId/Path when an id is in scope. See data-model.md → Context.
context view — A view mode that replaces a thought's children with the contexts in which the thought's value appears. Toggled with Option + Shift + S. The "inbound links" dual to the outbound parent-child links. State: state.contextViews, keyed by hashPath(path). See data-model.md → Context view.
contextChain — A Path that crosses one or more context views, split into its SimplePath segments. Path → SimplePath[] via splitChain. See data-model.md → contextChain.
copula — A finite form of "to be" (is, are, was, were) that Split Sentences treats as the boundary between a single sentence's subject and its predicate: the subject becomes the main thought and the predicate its child, with its leading article dropped. See commands.md → Split Sentences.
crossContextualKey — ${contextChain.map(head).join('')}|${id}. The React key for a thought that may appear at multiple positions when context views are active. Same ThoughtId produces different keys per occurrence. See layout-rendering.md → Keys.
cursor — The active thought, stored as state.cursor: Path | null. Indicated by the gray bullet ring. Distinct from caret. Setting the cursor does not set the browser selection; see cursor-and-caret.md.
cyclic context — In the context view, the context that is the nominal context's own parent, so navigating into it returns to where the context view was opened, e.g. a under a/m~. Descending into it produces a circular Path (a/m~/a/x), which the app tolerates. Everything else listed is a tangential context. See data-model.md → Context view recursion.
DataProvider — The single interface (DataProvider.ts) for storage backends. The active implementation is exported through data-providers/thoughtspace.ts.
dbQueue / freeQueue — Two halves of the push-queue split. dbQueue writes batches with local || remote set; freeQueue releases entries from the in-memory cache. See persistence.md → Push queue.
docId — The TreeCRDT document identifier for the thoughtspace. Equal to tsid. See persistence.md → The TreeCRDT client.
DragCanceled / DragHold / DragInProgress / Inactive — Values of LongPressState, the state machine for the drag/long-press subsystem. See drag-and-drop.md → State machine.
DropChild / DropEnd / DropCliff / DropUncle / DropGutter — Drop-target components for, respectively: dropping into an empty/collapsed thought, the end of a list, intermediate cliff levels, before the next hidden uncle, and the right-edge quick-delete panel. See drag-and-drop.md.
DropThoughtZone — ThoughtDrop (insert before the target) or SubthoughtsDrop (insert as a child). The semantic distinction every drop target reports.
EM_TOKEN — Sentinel ThoughtId ('__EM__') for the hidden system context where user settings (e.g. [EM, 'Settings']) are stored. See constants.ts.
expanded — state.expanded: Index<boolean>, keyed by hashPath(path). A thought's children are walked by linearizeTree only if its path is in this map. Expansion is derived from the cursor and the multicursor: a selected thought expands its ancestors but stays collapsed itself, so any reducer that changes state.multicursors must recalculate expanded. See expandThoughts.
fetchDescendants — Async iterable that does breadth-first traversal of thought IDs and yields { thoughtIndex, lexemeIndex } chunks. The actual pull engine. See persistence.md → fetchDescendants.
freeThought / freeLexeme — DataProvider methods for releasing a thought or Lexeme from the provider's in-memory cache. No-ops under TreeCRDT, which keeps the whole thoughtspace in one SQLite database; freeing memory means dropping entries from the Redux indexes. See persistence.md → Memory management.
generating — Flag on Thought set while content is being produced by AI. Distinct from pending (loading from storage). Generate Thought, Generate Emoji, Organize Thoughts, and Define Term use it as a display-only signal: empty thoughts show a command-specific placeholder ("Generating Thought", "Generating Emoji", or "Reorganizing Thought") and all generating thoughts and their notes shimmer in their own text color, preserving background highlights, without writing a pending value. The shimmer animates a gradient mask over the existing rendering so colors, backgrounds, native emoji and editable HTML stay intact. Emoji wrappers exist only in the displayed HTML and are not stored. generatingPlaceholder is the in-memory label for that empty-thought placeholder and is not persisted.
GLOBAL_ROOT_TOKEN — The root node of the TreeCRDT tree, and the value ROOT_PARENT_ID aliases. HOME_TOKEN, EM_TOKEN, and ABSOLUTE_TOKEN are inserted as its children during initialization. See constants.ts.
gesture — Swipe pattern for command activation on touch. Defined per command via the gesture field on Command. See commands.md → Gesture activation.
help genie — A glowing orb with a tapering, sparkling trail that flies over the app. The Help button in the Command Universe header and the learning genie button in the pinned command tooltip let it out and put it back. For now it follows the pointer or a finger, and can be sent to a point with moveHelpGenie. See learning.md → Help genie.
HOME_TOKEN — Sentinel ThoughtId for the home root. The path [HOME_TOKEN] represents the root thought itself; every regular Path starts with a child of HOME (or ABSOLUTE) and the root token is implied. See data-model.md → Path.
indent (horizontal autocrop) — As the cursor descends, the entire tree slides left so the cursor stays roughly center-screen. Multiplied by 0.9 per level so depth remains visually perceptible. See layout-rendering.md → Indent.
isTable / isTableCol1 / isTableCol2 / isTableCol2Child — Flags set on TreeThought when the parent / grandparent / great-grandparent has =view/Table. Drive the column-placement math in usePositionedThoughts.
jump history — state.jumpHistory: (Path | null)[] plus state.jumpIndex. Stack of past edit points navigable with the Jump Back / Jump Forward commands. New edits are prepended.
Lexeme — Object collecting all the contexts where a value (or any of its near-identical word forms — case, plurality, emoji variants) appears. Stored in state.thoughts.lexemeIndex keyed by hashThought(value). The "inbound links" view of a thought. See data-model.md → Lexeme.
linearizeTree — Selector that produces treeThoughts: TreeThought[] — an in-order traversal of every visible thought. Output drives layout. See layout-rendering.md → linearizeTree.
LongPressState — Enum (Inactive | DragHold | DragInProgress | DragCanceled) tracking the long-press / drag-in-progress state machine. Stored on state.longPress. See drag-and-drop.md.
materialization — TreeCRDT applying operations to its SQLite read model, after which client.onMaterialized fires. em ignores events produced by its own writes (identified by writeId) and refreshes Redux from the rest. See persistence.md → Change observation.
meta-attribute — See attribute.
ministore — Lightweight non-Redux store for ephemeral UI state, in /src/stores. Used when the value doesn't need to participate in undo/redo, persistence, or selectors (e.g. editingValueStore, viewportStore, scrollTopStore). A module may also create one for its own bookkeeping that must reset between tests — the pull queue's once-per-session favorites flag, the URL middleware's last path and cursor, the multiselect middleware's parked cursor — since every store the factory creates is restored by resetStores, while a module-level let would carry its value from one test into the next.
movePlacements — Index<ThoughtId | null> on PushBatch. Keyed by moved thought; the value is the sibling to place it after (null = first). Carries reorder intent from the action layer to TreeCRDT, which stores sibling order directly instead of by rank. See persistence.md → Order and placement.
multicursor — Multiple selected thoughts. state.multicursors: Index<Path> keyed by hashPath(path). Commands that support multicursor declare it via the multicursor field on Command. Drag picks up the full set into draggingThoughts. See commands.md → Multicursor.
nominal context — The thought whose context view is open, i.e. the thought whose contexts are listed in place of its children. m in a/m~.
=note — Meta-attribute that displays a smaller-text note under a thought.
Path — [ThoughtId, ...ThoughtId[]] — non-empty sequence of thought ids from root to a thought. Root itself is implied ([HOME_TOKEN] is the special case). May contain cycles when traversing context views. See data-model.md → Path.
pending — Flag on Thought indicating the id is known to exist (thoughtIndex[id] is set) but the real data hasn't been pulled from local/remote storage yet. UI renders placeholders; the pull queue fetches based on visible pending IDs.
permissionsStore — Ministore holding Index<Share> keyed by access token (one entry per device with access), persisted with idb-keyval under em-permissions:${tsid}. See permissionsStore.ts; CRUD in permissionsModel.ts.
=pin — Meta-attribute that keeps a thought expanded. Scoped variants: =children/=pin keeps all children of a context expanded (the replacement for the old =pinChildren), and =descendants/=pin keeps the entire subtree expanded. =pin is also pre-loaded eagerly during fetchDescendants to avoid a flash of expanded children before =pin/false resolves. See metaprogramming.md.
pull queue — pullQueue.ts middleware that, on every action, computes the visible thought IDs and triggers pull for any pending ones. Debounced 10 ms, throttled 100 ms. See persistence.md → Pull queue.
push queue — pushQueue.ts Redux enhancer that drains state.pushQueue after every action, partitioning into dbQueue (writes) and freeQueue (cache release). See persistence.md → Push queue.
quick drop — Right-edge invisible 2em-wide drop panel mounted only while a drag is in progress, used for quick-delete. Implemented by DropGutter / QuickDropController. See drag-and-drop.md.
rank — number on Thought that determines sort order among siblings. Unique per parent; absolute value irrelevant. Fractional and negative values let inserts avoid renumbering. Rank is the only order the render path reads: a parent's =sort takes effect by renumbering its children's ranks, not by re-sorting at render time. See data-model.md → rank.
reducerFlow — util/reducerFlow.ts — composes a list of reducers into a single reducer. Standard pattern in actions/.
replicaId — The 32-byte id TreeCRDT mints local operations under, derived from clientId by clientIdToReplicaId. A low-level CRDT identity, not an auth identity.
replication — Loading thoughts out of local storage and into memory. replicateTree walks a subtree in the background without populating Redux; the pull queue is the foreground path. syncStatusStore.replicationProgress tracks it for the UI.
resetStores — The one test boundary for module-level state, in stores/ministore.ts. Restores every ministore to its initial value, after running any reset a module registered through registerReset — for state whose restoration is an action rather than a value, such as the debug log's buffer and animation-frame heartbeat. Called by initStore and createTestApp at setup, by cleanupTestApp before it drains timers, and after every unit test by setupTests.ts. See testing.md.
ROOT_CONTEXTS — [HOME_TOKEN, ABSOLUTE_TOKEN]. The two top-level contexts.
ROOT_PARENT_ID — Sentinel ThoughtId for the parent of the root thoughts. An alias for GLOBAL_ROOT_TOKEN, the TreeCRDT tree root. Distinct from HOME_TOKEN / ABSOLUTE_TOKEN, which are the root thoughts; ROOT_PARENT_ID is their parent. getThoughtById reports it as the parentId of any thought whose TreeCRDT parent is the tree root.
session lock — Exclusive Web Lock named em-treecrdt-session:${tsid}, held for the lifetime of the page so only one tab opens a thoughtspace at a time. A second tab renders ThoughtspaceInUse instead of the app. See persistence.md → Single-tab access.
shortcut — Legacy term for command. The folder was renamed /src/shortcuts → /src/commands; some doc references and helper names persist.
SimplePath — A Path branded as having no cycles (no context-view crossings). Required by code that needs a single contiguous context. Get one via simplifyPath or by structurally guaranteeing it and casting. See data-model.md → SimplePath.
=sort — Meta-attribute that sorts a context's children, replacing their manual order by renumbering their ranks. Options: Alphabetical, Created, Updated, Note (sort by =note value), each Asc or Desc.
splitChain — splitChain.ts — splits a Path into SimplePath[] at every context-view boundary. Inverse: contextChainToPath.
=style — Meta-attribute carrying CSS styles. Variants: =children/=style (apply to direct children), =grandchildren/=style (one level deeper).
tangential context — In the context view, a context from a different part of the tree than the one the view was opened in — every context listed except the cyclic context, e.g. b under a/m~. Since a tangential context has not been pulled through the cursor's ancestor chain, it is also the loading case fetchDescendants handles: it enqueues the parent of any thought whose parent isn't loaded, so the ancestor chain resolves. See the comment "load ancestors of tangential contexts" in fetchDescendants.ts.
Thought — In-memory record under state.thoughts.thoughtIndex. Only part of it is persisted: TreeCRDT stores a ThoughtPayload per node and derives parentId, rank, and childrenMap from the tree on read. See data-model.md → Thought and persistence.md → Document model.
ThoughtId — Branded string identifying a thought: 32 lowercase hex characters (128 bits), the format TreeCRDT requires for a node id. Minted by createId. See @types/ThoughtId.ts.
ThoughtPayload — The bytes stored on a TreeCRDT node: JSON-encoded value, created, lastUpdated, updatedBy, and optional archived. See payload.ts.
thoughtspace — A user's complete thought tree, identified by tsid. The unit of sharing: switching ?share=<tsid> switches the app onto a different thoughtspace.
ThoughtspaceRuntime — Lifecycle interface around the active provider (thoughtspace.ts): acquireAccess, init, drop, waitForIdle, persistPushQueueBatches. Implemented for TreeCRDT in runtime.ts.
TreeCRDT — The CRDT that backs local persistence: one operation-based tree per thoughtspace, materialized into SQLite (wa-sqlite, OPFS-backed) and optionally synced over a WebSocket. See persistence.md.
TreeThought / TreeThoughtPositioned — The two parallel lists produced per render: visible thoughts in document order, and the same with x/y/width/height/cliff filled in. See layout-rendering.md → Two lists.
tsid — Thoughtspace ID. 21-char nanoid in localStorage. Scopes everything per-thoughtspace: the TreeCRDT docId, the OPFS database file (/treecrdt-em-${tsid}.db), the session lock, and the permissions key. Override with ?share=<tsid>.
undo step — What one Undo reverts: one patch, or a directional pair when trailing navigation belongs with the preceding change or an edit gives a newly created thought its value. A command transaction may collect several underlying actions into one patch. The undo slider uses the same grouping. See commands.md → Undo history and the undo slider.
updatedBy — clientId of the writer. Stamped on every Thought and Lexeme write. (Self-originated materialization events are filtered by writeId, not by this field.)
updateThoughts — The action (actions/updateThoughts.ts) that mutates Redux and queues a push. The push queue persists those batches through the active data provider's updateThoughts.
=view — Meta-attribute controlling render mode. Options: List (default), Table, Prose.
VirtualThought — Component that wraps each rendered thought, measures its height, and reports back via onResize. See layout-rendering.md → VirtualThought.
write barrier — writeBarrier.ts. Serializes em → TreeCRDT persistence and exposes an idle barrier, so a materialization refresh cannot reapply stale rows over newer optimistic state. Also mints each write's writeId.
writeId — em-local:${sourceId}:${n}, attached to every local TreeCRDT write and echoed on the materialization changes it produces. Lets this tab recognize and skip its own already-applied writes.