Root cause (owner repro, verified in a real browser 2026-09-06): the
five navbar views (Chat, RAG, Sources, Tuning, History) were separate
HTML documents, so a navbar click was a REAL cross-document navigation
— the chat page unloaded, the in-flight SSE fetch was aborted, and the
phase-48 teardown (app/api/chat.py `finally`, "chat: turn cancelled")
stopped the model. Observed: send question -> click RAG mid-stream ->
click Chat -> the answer never finished: no `query_log` row, and on
return a dangling question with no brain record (the pre-token pagehide
partial persist skips because `acc` is empty).
Phase-48 LOCKED-DECISION REFINEMENT (owner-confirmed 2026-09-06,
flagged per AGENTS.md rule 3, not silently deviated): "real navigation
cancels the fetch" now means LEAVING THE APP — tab close,
external/other-document navigation, the Stop button. In-app navbar
switches are client-side view switches and no longer cancel.
Fix — Option A (SPA shell), chosen over B (Service Worker owns the
stream) and C (server-side turn registry + resume):
- frontend/index.html is the shell: ONE `<main id="main">` holds the
five `<section class="view">` blocks; hidden views carry BOTH
`hidden` and `inert` (WCAG — no focus/keyboard traversal). The
shared header, the single `doc-modal-*` skeleton, and the
`#app-version` footer each exist exactly once; the per-view copies
from the four folded pages are dropped.
- New frontend/assets/router.js (vanilla module — no framework, no
bundler, No-CDN rule intact): lazy-imports a view module on FIRST
show only (mount-once, hide-forever — the chat view's in-flight SSE
reader persists across switches; that persistence IS the fix);
intercepts same-shell navbar links with preventDefault +
history.pushState (never a document load); handles popstate; single
writer of `.nav-link` active state (is-active + aria-current),
document.title, and the per-view meta description (values carried
over from the old pages' heads, brand-resolved at write time).
- Each folded page's JS becomes `export async function mount(root)` —
root-scoped queries; `initSharedHeader()` dropped (the header boots
once in the shell via the chat module; the admin flag comes from the
same cached `fetchIsAdmin()` promise — zero extra requests).
- app/main.py: a small list-driven route factory serves the shell for
/tuning.html, /sources.html, /git-sources.html, /history.html —
registered AFTER the API routers and BEFORE the static catch-all
(routes-first). The phase-33 caching middleware applies no-cache +
`?v=` rewriting unchanged; app/core/caching.py needed NO change
(the view paths did not change — pinned by the integration tests).
- The four old view .html files are DELETED (one source of truth);
deep links to the old URLs keep working (the router picks the view
from the pathname); `/?chat=<id>` is unaffected; the Containerfile
bundles router.js (inlining the lazy view modules) and drops the
folded page files.
- app/schemas.py: HistoryTurn.text cap 4000 -> 32000 — the shell
keeps long saved answers in the chat, and the old cap (stricter than
the 24_000-char total history budget) 422-rejected any second turn
in such a chat (found by the phase-42 E2E suite on the shell).
Boundaries: login.html, shared.html, doc-edit.html, document.html
REMAIN separate documents (flow pages, not navbar tabs); a mid-stream
navigation to doc-edit/document.html still cancels per phase 48
(follow-up candidate, out of scope). The SSE API is unchanged. Real
departures still cancel the turn — phase 48 intact (pinned by
tests/e2e/test_stop_generation.py, unchanged, and by the new suite's
real-departure control).
Tests:
- Phase-20 suite REWRITTEN to the new semantics
(tests/e2e/test_sources_midstream_bug.py): a navbar switch no longer
cancels — the stream survives the switch and the FULL answer
settles; the pagehide partial persist REMAINS for real departures
(the partial's exact shape — first streamed chunk prefix, no done
metadata — is still pinned there).
- NEW story suite tests/e2e/test_nav_switch_keeps_stream.py (mock
LLM): the owner repro (send -> RAG mid-stream -> Chat: window
sentinel survives = same document, FULL answer, exactly one brain
turn in bor.chat.v1, exactly one settled query_log row, auto-saved
row matches) + the same mid-stream switch against the other three
views + the real-departure-still-cancels control + the no-switch
baseline.
- tests/unit/test_frontend_router.py: source-level pins of the router
invariants (click interceptor targets ONLY same-shell view paths,
pushState-only switches, mount-once guard, hidden+inert pair,
single-writer active state/title); shell-route integration tests
(each folded path serves the shell with no-cache + `?v=` body; a
non-view path still 404s); the file-reading unit pins re-pointed at
the shell (the four view files are gone — the shell is the source
of truth).
Verification (this commit): full suite green — 1565 unit+integration
tests, app/ coverage 99% (>90% floor); ruff + pyright clean; the
phase's E2E suites green in isolation (house protocol, AGENTS.md rule
9). Owner repro verified in a real browser against the real LLM
(dev server :8010, headful Chromium): "tell me about everquest" ->
RAG mid-stream -> Chat — the answer completed with one brain bubble
and no error banner, `query_log` gained exactly one settled row
(deflected=True: the dev KB holds no EverQuest docs — the settle, not
the topic, is the proof), zero "chat: turn cancelled" lines for that
turn; the control (real navigation to /shared.html mid-stream) still
cancelled (no settled row, the cancel line logged, the partial
persisted on return). Screenshots: .agents/screenshots/76_manual_*.
Phase 76 (76_spa_nav_shell) complete — moved to
.agents/phases/complete/.
- task 01: relocate the .chat-actions row (New chat + Share, comments byte-identical with a Phase 65 note) from the top of the column to the bottom of .chat-shell, directly above the composer
- task 02 (owner-locked A1): wrap the row + #composer in ONE sticky .chat-bottom unit (position: sticky; bottom: env(safe-area-inset-bottom, 0), no z-index) — the pills stay at the bottom of the screen at every scroll position and settle into flow above the footer
- task 03 (owner-locked A2): right-align the bottom row to the column's right edge (justify-content: flex-end), mirroring the right-aligned Save-as-doc corner; the five action pills share one 44px / 999px-pill geometry
- task 04: dedicated Playwright suite tests/e2e/test_bottom_chat_actions.py (resting geometry, the A1 pin across the sticky range, A2 alignment + DOM order + mobile stack + 360px overflow bound + 44px touch targets, New chat / Share click-through) — green in isolation
- task 05: regression matrix green in isolation (pinned_composer 4, save_share_ux 5, chat_persistence 4, share_chat 4, chat_history 5, smoke 3); full gate green — unit + integration pass, app/ coverage 99% (>90%), ruff + pyright clean
ducoterra