The trace exporter renders one persisted lash session — or a tree of sessions joined by continue_as handoffs and spawn_agent subagents — into a single self-contained HTML document. The visual language matches the rest of the docs (warm-iron / fast-amber). The forensic affordance is two-edge-aware: handoffs are linear seams in the same view; subagents are drill-in cards into their own full view.
Both continue_as and spawn_agent create new sessions on disk with parent_session_id set, but they are semantically and visually different — flattening them under one shape is what made the previous exporter feel wrong. Lash's runtime distinguishes them as SessionRelation::Handoff and SessionRelation::Child; the exporter mirrors that distinction in the rendered surface.
| Edge | Tool | Cardinality | Lifecycle | Visual treatment |
|---|---|---|---|---|
| Handoff | continue_as |
1 → 1 terminal | Parent ends; successor takes over with seed and task. |
Inline divider. The successor's entries continue in the same view, behind a sodium-bracketed seam that names the seam. |
| Subagent | spawn_agent |
1 → N blocking | Parent waits for the child to submit, then resumes. | Drill-in card. Click into the subagent's own full view (same hero, same controls). Breadcrumb tracks the path back. |
Continue_as is linear, so the natural reading is one transcript that crosses session boundaries. The seam is a full-width band with sodium hairlines top and bottom, the task in display type, the seed broken into projected vs global entries, and a hairline-divided stat strip — the four pieces of state the reader needs to understand what was carried forward and what was left behind.
Take the auth-file inventory and the migration summary; produce a single ranked list of compliance touchpoints. Each item gets a one-line rationale and an effort estimate. Stop when the list is < 12 items.
Spawn_agent is blocking but its result is a separate unit of work. Inlining the child transcript inside the parent's tool entry would force a width-cascade and lose the subagent's full hero / controls / minimap. Instead, the exporter renders the spawn_agent call as a click-through card and gives the subagent its own view. The lichen accent keeps the child visually subordinate to the sodium handoff seam.
Summarise migrations/ schema changes since v3. Flag any change that touches identity, session, or token columns.
The breadcrumb is the primary "where am I" affordance — sticky at the top of the viewport so navigation context never scrolls away. It shows the lineage from root through any subagents the reader has drilled into. The separator is a quiet ash ›; sodium-tinted arrows are reserved for the lineage strip's actual edge glyphs (↪, ▾) one row down, so the two bars don't compete for the same accent.
An end-to-end mockup with three views (root → db_migrations → migration_v5) backed by synthetic but realistic content. Click any drill-in card or breadcrumb step to navigate. Browser back works through history.pushState. Resize the iframe to see responsive behavior.
The renderer is additive — single-session export still works as it always did. Multi-session detection is automatic.
Given a root .db path and a trace JSONL, tree::load_tree_from_paths scans the sessions directory, keeps every store reachable through parent_session_id chains, partitions LlmPromptSnapshots by context.session_id, and classifies each child by inspecting the parent's chronological for the matching tool call: spawn_agent ⇒ NodeRelation::Subagent, continue_as ⇒ NodeRelation::Handoff, otherwise fall back to Subagent (handoff is rare and continue_as always emits the successor's session id). No schema change to the on-disk store.
A view is a chain of sessions joined by handoffs; the root and every subagent are heads of their own views. html::write_view walks the chain and writes one <section class="view"> per head, with successor entries inlined behind handoff dividers and spawn_agent calls converted into drill-in cards that target the subagent's view.
Each view is rendered up-front and toggled by a tiny IIFE that reads window.__lashTraceTree (a serialized list of {id, label, sid, parent}, one entry per view head — root and each subagent — not one per session; id and parent are view IDs, sid is the head session's short id). Click handlers on [data-go] elements (drill-in cards, breadcrumb segments, lineage pills) call history.pushState and swap the active .view. The browser back button does the right thing through popstate.
Sodium is reserved for the active edge — handoff seams, the breadcrumb's current step, the user's intent. Lichen marks the subagent affordance — drill rails, drill arrows, child status pills. Filter chips read as quiet chalk by default and gain a sodium strikethrough only when the user has actively filtered something off, so the controls strip never floods the page with accent. Ash structural lines do everything else.
Single self-contained HTML; tokens, fonts, CSS, and JS all inlined.
lash-export/src/tree.rsTree discovery and edge classification. Returns a LoadedSessionTree with one LoadedSessionNode per discovered session; each carries its own chronological projection, partitioned LLM prompts, and the list of subagent edges anchored by parent call_id.
lash-export/src/html.rsrender_tree is the multi-view entry point. write_view, write_view_hero, write_lineage, render_handoff_divider, and render_drill_card own the new visual elements; the existing message/tool/RLM-step renderers are reused unchanged.
lash-export/src/html_assets/style.cssTokens are appended at the bottom under "multi-view: breadcrumb, lineage, drill, handoff". The base trace stylesheet stays intact for single-session exports; multi-view rules only activate when the page contains .view sections.
lash-export/src/html_assets/script.jsThe view-switcher IIFE at the bottom reads window.__lashTraceTree, wires [data-go] click handlers, renders the breadcrumb, and listens for popstate. It exits cleanly if the tree global is absent (single-session export).