feat(render): per-component fallback API + readiness gate#252
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Card-shaped placeholder mounted when a registered component is not yet ready to render (any state-bound prop unresolved). Used as the fallback for registry entries that don't declare their own, and as the top-level surface fallback for empty specs.
Registry entries now accept either a bare Type (legacy) or a
{ component, fallback? } object. defineAngularRegistry normalizes
both shapes; bare entries get DefaultFallbackComponent. The
AngularRegistry interface gains getFallback(name) for downstream
consumers (render-element) to look up the fallback class.
Per-element readiness check: if any state-bound prop resolves to undefined, mount the registry's fallback component instead of the real one. Once real mounts, a latched mountedReal flag prevents future reversion — subsequent re-renders only push new input values via Angular's reactive system. null counts as ready (it's a meaningful resolved value); only undefined triggers fallback. Adds @analogjs/vite-plugin-angular to the render lib's vitest config + a tsconfig.spec.json so component tests with inline templates JIT-compile. Pre-existing pipeline-logic tests still pass; new fallback-gate tests use TestBed.createComponent.
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Signal writes inside computed are an anti-pattern even when deferred via queueMicrotask. Move the monotonic mount latch into a constructor effect that watches notReady + the resolved component class. Behavior unchanged; fixes the signal-graph hazard flagged in PR review.
PR A widened ViewRegistry entries to Type | RenderViewEntry. The
markdown-children resolver indexes the registry directly (not via
defineAngularRegistry) and was implicitly typed as Type. Narrow at
the call site by checking 'typeof entry === function' (bare Type)
vs object form ({ component, fallback? }), returning the component
in either case.
This was referenced May 12, 2026
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* feat(chat): A2UI envelope-args shape normalizer
Accepts four argument shapes observed in the streaming-envelope-tool
spike: canonical {envelopes:[...]}, singular {envelope:[...]}, positional
keys {0,1,...}, and flat single envelope. Returns a canonical envelope
list or null. Shared shape with the Python normalizer in PR 2.
* feat(chat): A2UI surface-store applyPartialArgs entry point
Adds a live-stream feed alongside apply(). Records the tool_call_id so
downstream consumers (content classifier) can short-circuit duplicate
envelope dispatch when the final wrapped AIMessage arrives carrying the
same content the live stream already applied.
* feat(chat): A2UI partial-args bridge for streaming envelopes
Subscribes to LangGraph custom events ('a2ui-partial') and feeds the
A2UI surface store envelope-by-envelope as the parent LLM streams its
tool_call.arguments JSON. Uses @cacheplane/partial-json to extract
structurally-complete envelopes from the growing args string.
Safety net: synthesises beginRendering immediately after the first
surfaceUpdate (targeting component id='root' or the first component),
so the surface mounts and the per-component fallback gate (PR #252)
fires while dataModelUpdates stream in — without waiting for the LLM
to emit beginRendering at the end of its envelope list. Repeated
beginRendering on the same surface is idempotent in the store.
Poison detection: a JSON-prefix validator runs ahead of the partial
parser to detect structurally invalid streams (the partial-json parser
silently halts on bad input rather than throwing), so malformed
arg streams are dropped and subsequent valid pushes are ignored.
* feat(chat): wire partial-args bridge to agent.customEvents
The chat composition subscribes to LangGraph custom events of name
a2ui-partial and forwards the cumulative args strings to the bridge.
Effect tracks last-processed index so re-renders don't re-dispatch.
Adapters that don't expose a customEvents signal (the runtime-neutral
Agent contract makes it optional) are tolerated via feature detection;
those continue to rely on the wrapped final-message classifier path.
* feat(chat): export partial-args bridge + normalizer
* chore: regenerate api-docs for partial-args bridge
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…dler (#262) * feat(examples-chat): A2uiPartialHandler sidebands streaming envelopes Async callback handler tracking per-tool_call_id cumulative arguments from on_chat_model_stream events. Each growth in the cumulative string dispatches an a2ui-partial custom event carrying {tool_call_id, args_so_far}; the frontend partial-args-bridge consumes these and feeds envelopes into the A2UI surface store as they parse. * feat(examples-chat): wire A2uiPartialHandler to generate node Attached only when gen_ui_mode='a2ui'. Sidebands the parent LLM's tool_call_chunks for render_a2ui_surface as a2ui-partial custom events. Together with the frontend partial-args bridge (claude/genui-streaming- frontend-bridge) and the envelope-tool refactor (claude/genui-streaming- envelope-tool), this realises the per-component fallback transition wired by PR #252 — surface mounts on first surfaceUpdate, components flip from fallback to real as dataModelUpdates stream in.
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…rk (#271) Brings the canonical smoke checklist current with 29 PRs that landed between Phase 7 (#239) and today without checklist updates. Specifically: Updated sections: - chat-debug devtools — replaced bottom-drawer model with floating launcher + status pill + switch (PRs #249, #251) - Control palette — palette v2 (status pill, shadcn-styled panel, PR #244) - Generative UI / A2UI surfaces — single-bubble invariant (PR #255), parent-emits-envelopes architecture (PR #259), wrapped-content + tool_calls coexistence (PR #255), envelope reorder - Server-side wire format — tool_calls preserved on the final AI - Replaced 'Multi-thread' section with 'Sidenav (thread management)' reflecting the permanent semantic <nav> + Active/Archived sections (PR #253) and removing the old palette-toggled drawer model Added sections: - Cmd+K history search — palette open/search/select/close, archived result subtitle, keyboard navigation (PR #253) - Per-row thread actions — kebab menu order per state (active, pinned, archived), rename + pin/unpin + archive/unarchive + delete flows (PRs #258, #260, #267) - Thread titles — first-user-message derivation, idempotent writes, manual rename precedence (PR #242) - Progressive A2UI streaming — per-component fallback transition observable during streaming window (PRs #252, #261, #262, #268, #269) - Inline checkpoint markers — render between messages during multi-step runs (PR #243) - Responsive sidenav — viewport breakpoints, auto-collapse behavior (PR #240) Total: ~58 new check items across 6 new sections, plus rewrites to 5 existing sections. Original 333-line checklist → 391 lines / 237 check items.
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Summary
Adds first-class per-component fallback rendering to
@ngaf/render. Registry entries now accept an object shape:<render-element>mounts the fallback whenever any state-bound prop resolves toundefined. Once the real component mounts, a monotonic latch prevents future reversion to fallback — subsequent state changes flow through as reactive input updates.DefaultFallbackComponentships as the implicit fallback for entries that omit one.This is the rendering primitive that unlocks progressive GenUI rendering in
<a2ui-surface>— each A2UI component's data bindings resolve at their own pace, and each slot transitions skeleton → real in place as its bindings populate.Spec:
docs/superpowers/specs/2026-05-11-progressive-genui-bubble-coalescing-design.md.Test plan
nx test rendergreen (registry tests, render-element fallback tests, default-fallback tests)nx build render+nx lint rendergreen