changelog

Sequence diagram: the sequence family is now first-class. Lifelines and actors auto-size to fit their head labels (including multi-line labels via per-line tspan), foot bars render by default to close the diagram, lane pitch is computed per-pair so self-message arcs grow to fit their label and clear the source lifeline, self-message U-shapes render with rounded interior corners, the lifeline header band is treated as a label-placer obstacle so first-message labels never dip into the header zone, and async messages emit an open arrowhead. The new sequence.note element anchors over a single lifeline or spans a range, and containerType: "fragment" with extensions.operands renders alt-fragment branch dividers with their guard text protected from label collisions.

The new /examples library showcases agent-native diagram workflows with before/after revision diffs, CI/CD recipes, and curated agent artifacts across every diagram family. The first sequence-diagram showcase walks through an HTTP /checkout handler request lifecycle (eight lifelines, twelve messages, an alt fragment around payment retry, and a fire-and-forget queue publish) and shows the diff a reviewer sees when an agent maintains the diagram alongside the handler.

ER diagram: compartmented entities (er.entity and er.weakEntity with extensions.columns) grow to fit the longest column row and full row count whenever the author-declared layout.width or layout.height is smaller than the intrinsic content size. Declared dimensions act as a floor, not a cap, so a default 150x60 layout still renders correctly when columns carry long names. Mirrors the canvas auto-extension semantics.

Two new normalizer diagnostics help agents self-correct before the engine reaches layout. MISSING_DIAGRAM_FAMILY emits when a scene omits the top-level diagramFamily field and lists the seven valid values in data.allowedValues. LAYOUT_ABSOLUTE_AT_ORIGIN emits when a scene declares layoutStrategy: "absolute" but every node sits at (0, 0), the signature of an agent that meant to omit coordinates and rely on auto-layout.

State-machine and BPMN transition labels of the form EVENT [guard] / action now render with three distinct typographic runs inside one text element: the event in the regular edge weight, the guard at smaller size and muted colour, and the action italicised. The eye locks onto the event name first while the guard and action stay legible without dominating the canvas. Detection is content-based and family-agnostic; plain labels keep their existing single-style rendering.

Architecture: nodes declared with nodeType: "externalSystem" now render with a dashed outline and muted fill so third-party services read as clearly outside the system boundary. Internal services keep their solid fill and crisp outline, giving readers an immediate visual separation between owned and external components.

The normalizer now accepts scenes where diagramFamily, layoutStrategy, or other document-root fields appear nested inside document or scene, hoists them to the correct location, and emits an OUTER_FIELD_NESTED diagnostic so the agent learns the canonical shape. A common authoring slip that previously broke layout selection now produces a working diagram with a guidance code attached.

When two or more edges connect the same source-target pair across one rank gap and at least one carries a label, the layered planner now inflates the bundle endpoints by the cumulative label-stack height so the existing funnel passes can redistribute anchors across the inflated face. Labels naturally place at distinct midpoint positions instead of clustering at one anchor, and the placer succeeds without further intervention.

The label placer previously fell through to the polyline midpoint whenever every candidate position overlapped an obstacle, silently bypassing the spatial index and dumping labels on top of nodes, dividers, and other labels. It now tracks the best clean candidate and the minimum-overlap candidate in parallel, returning the clean one when available and otherwise the position that grazes the smallest obstacle area. Thin features (fragment dividers, header bands) are preferred over thick ones (node bodies), matching how a human would resolve the conflict.

ER diagram: the playground opens on the ER tab so column-row anchored edges, Crow's Foot auto-inference, PK fallback routing, and entity auto-sizing are visible on first paint. Architecture moves to the second slot.

State-machine diagrams pick up three quality improvements in one pass: duplicate diagnostic codes are deduped before they reach the agent, fan-in labels at a shared target collapse onto a single anchor row instead of stacking, and back-edges that cannot route cleanly drop into the canvas whitespace below all nodes as an obstacle-aware orthogonal U-hook. The U-hook keeps loopbacks clear of unrelated shapes instead of arcing through them, matching how mainstream BPMN and state modellers draw retry edges.

The canvas now reserves 60 px below the bottom-most rendered element instead of 40 px. Sequence foot bars, ER row bottoms, and workflow terminator events sit comfortably inside the canvas instead of crowding the lower edge. The constant is shared between the centering pass and final canvas sizing so the two stay in sync.

When a single source spawns several edges that travel across more than one rank before splitting, the router now aligns their initial trunk segments so the group reads as one bus rather than a frayed broom. Conversely, edges that share a label and converge on a single target merge into one trunk before terminating, giving hub patterns and shared-event fan-ins the visual coherence they had on simple source-target pairs.

The canvas-tightening pass now respects the natural aspect ratio of the laid-out content instead of producing fixed-shape backgrounds. Tall state machines no longer waste horizontal space and wide workflows no longer truncate; the canvas snaps to the shape the content wants. A single source of truth drives both the centering pass and the final canvas dimensions so the two never diverge.

Generic frames and lane headers now render with smaller, muted title typography so the frame reads as ambient context rather than competing with its contained nodes. The title text knocks out the frame border behind it so the label is never bisected by an outline stroke. Applied uniformly across themed and no-theme renders.

Edges authored without an explicit style.arrowhead now render with a filled target-end triangle by default. Agents that omit the field get the direction-conveying arrowhead readers expect on flow diagrams, while agents that set arrowhead: "none" or pick a different style keep full control.

Default node label padding moved from 12 px to 14 px so text sits with visible margin inside the shape rather than crowding the outline. The label placer now treats sibling edges as obstacles and staggers parallel-bundle labels along the path so two-edge bundles that share a midpoint no longer drop both labels on the same coordinate.

UI flow: card screens narrow the funnel anchor span on east and west faces so edges no longer exit through the title-bar seam, and the polish bundle lifts text and outline contrast to WCAG AA across the family. Default arrowheads, shape-core targeting, and title font alignment land in the same pass so authored UI flows render with consistent typography and clearly-anchored connections.

The canvas-centering pass can now shift content upward when the planner placed it low. Previously a defensive clamp refused negative shifts, so asymmetric workflows and state machines (where one branch fans further than the others) ended up with a huge top margin and almost no bottom margin. With the clamp removed, an 18-state workflow that rendered with an 824 px top margin and a 207 px bottom margin in a 1600 px canvas now renders centred at 515 px on each side.

Workflow: decision diamonds authored as workflow.decision place their label inside the shape, matching generic flowchart convention. Previously the label floated below the diamond because the renderer grouped workflow.decision with the BPMN-spec gateway types, which intentionally reserve label space outside the shape for their marker glyphs. The four workflow.gateway* types keep their external-label BPMN treatment, and agent guidance across MCP and the docs nudges toward workflow.sequenceFlow for directional edges and workflow.decision for plain decision diamonds.

Edge paths now run through simplifyPath after the funnel and channel-routing passes, so sub-pixel interior segments produced when source-funnel and target-funnel shifts collide are collapsed before the renderer sees them. Previously a hairline residual could survive to the SVG output, misorienting an arrow marker or producing a barely-visible bent path.

The canvas now includes routed edge polylines when computing its bounds, so back-edges and U-hooks that arc above the top-most node no longer get sliced by the canvas edge. The same pass keeps anchor bounds in step with shape bounds during the centering shift, so when two or more edges share a target face the terminal segments stay pinned to the shape perimeter instead of drifting tens of pixels off the target. Visible on dense state-machine and architecture diagrams where multiple edges converge on the same node.

The router's obstacle-grazing detection now treats sibling node outlines as hard boundaries, so a candidate path that touches a neighbouring shape's edge is rejected before it reaches the renderer. Previously a path could clip a neighbour by a fraction of a pixel and pass the cleanliness check, leaving the edge appearing to enter and exit through an unrelated node.

Sequence diagram: a sequence.note with a single extensions.anchor value now centres OVER the named lifeline instead of placing to the right of it. The previous 'right of' contract was idiosyncratic and produced broken output for notes anchored to the right-most lifeline (they hung off the canvas edge, forcing auto-extension). Multi-anchor span semantics (extensions.anchor: ["a", "b"]) are unchanged. Authors who relied on the old offset should switch to a multi-anchor span or move the anchor.

The @zindex-ai/mcp npm package now talks to api.zindex.ai exclusively. Local mode is removed and ZINDEX_API_KEY is required for every tool call. Bundle size drops from 802 KB to 38 KB, agents always get persistence and revision history through dsp_create_scene, and the hosted state platform is the single source of truth. Set ZINDEX_API_KEY in your MCP host config; ZINDEX_API_URL defaults to the production host.

ER edges now anchor at the FK column row inside each entity, precisely connecting to the column that carries the foreign key relationship. When an edge's label matches a column declared in either endpoint's extensions.columns, the engine auto-promotes the edge to a column-row anchor and drops the label - the column position carries the FK identity. Agents can also set endpoint.column directly. Set style.forceLabel: true on an edge to keep its label visible.

The layout engine now automatically expands the scene canvas when auto-positioned nodes overflow the declared dimensions. A CANVAS_AUTO_EXTENDED diagnostic is emitted so agents know the canvas grew. Declared dimensions are treated as a minimum, not a hard cap - no more clipped diagrams when layout is denser than expected.

Multiple edges arriving at the same target port are now fanned across adjacent anchor slots. Previously, edges sharing an exact port produced visually identical paths that stacked on top of each other and rendered as a single line.

When a node has multiple outgoing edges leaving the same face, the router now distributes their exit anchors evenly along the face. Previously, hub fanout patterns - an ER table with many child relationships, or a service node with several outbound connections - could collapse onto one anchor and read as a single overloaded line. Bundled edges that intentionally share a trunk segment are preserved.

Edge strokes in dark and sketch render themes now use higher contrast values, improving legibility on dense diagrams. Container outline visibility in the sketch theme was also raised.

The built-in Flow example in the playground has been replaced with a richer Payment Processing reference diagram that demonstrates gateway routing, parallel flows, and service integrations at a realistic scale.

Requests to zindex.ai/ with Accept: application/json now return a machine-readable JSON document with the full API surface, schema locations, MCP endpoint, and usage instructions. Agents that call the root URL directly get structured onboarding without parsing HTML.

A pill control on the homepage lets you switch between the human-facing marketing view and the agent-facing raw JSON view, so you can see exactly what an agent receives when it discovers the platform.

The JSON panel now sits below the rendered diagram rather than beside it, giving diagrams more horizontal space. A copy button was added and the hide/show toggle was removed to simplify the layout.

Inter and JetBrains Mono are now served from the Zindex CDN via @fontsource. No requests are made to Google Fonts.

Edges that share horizontal or vertical corridors are now routed through dedicated channels so they no longer overlap. Dense diagrams with many parallel connections render as clearly distinct paths rather than a single merged stroke.

The order constraint type lets you pin the relative layout position of two nodes - useful when the diagram has a canonical reading order that the auto-layout algorithm should preserve regardless of edge direction.

Pools, lanes, and containers can now participate in auto-layout. The engine sizes and positions frames from their child nodes. UML sequence activation bars are placed automatically based on message flow.

Node labels automatically switch between light and dark text based on the perceived luminance of the node's background fill. Custom-colored nodes no longer require manually setting a contrasting label color.

A new updateScene op type lets agents modify scene-level metadata - title, palette, layout strategy, diagram family, and canvas dimensions - after the scene has been created, without recreating it.

Scenes now support a palette field that maps semantic color names to hex or oklch values. Nodes and edges can reference palette tokens by name, making it straightforward to apply brand or corporate color schemes across an entire diagram.

Edge labels are now positioned on the edge stroke rather than floating above it, and a background rectangle is rendered behind each label to prevent it from blending into crossing edges or node fills.

GET /scenes/:id omits the computed layout section by default. Pass includeComputed=true when you need bounding boxes and routed edge paths. This significantly reduces response size and token consumption for agents that only need scene state.

A ground-up rewrite of the layout engine ships as the new default. The engine handles node placement, edge routing, label positioning, and frame sizing in a single integrated pipeline. Agents can omit all coordinates and the engine produces clean, readable diagrams automatically.

The layout engine generates multiple candidate arrangements and scores each on edge crossings, bend count, symmetry, and whitespace balance. The highest-scoring layout is selected automatically - no author tuning required.

Nodes with many connections now bundle their edges into shared trunk segments before branching to individual targets. This reduces visual clutter in diagrams with central hubs such as API gateways, message brokers, and load balancers.

Pass diffFromRevision to dsp_render_scene to render a color-coded diff between two revisions of a scene. Added elements are highlighted green, removed elements red, and modified elements amber.

A new uiflow diagram family renders screen and modal nodes with appropriate chrome (title bars, navigation affordances) and routes transition edges as user-gesture flows. Suitable for product wireflows and onboarding sequence maps.

BPMN workflows and UML sequence diagrams were both elevated to excellent rendering quality. Event circles and gateway diamonds now use external labels, activation bars auto-place on lifelines, and combined fragment frames render with correct transparency.

The router now treats all node bounding boxes as hard obstacles. Edges that previously cut through nodes on busy diagrams are re-routed around them.

Layout results are now cached by a content fingerprint of the scene. Repeated renders of an unchanged scene skip the layout pass entirely, significantly reducing latency for high-frequency render workflows.