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What does registering a right-panel tab actually cost? #112
Description
Activity
- added a parent issue
on Aug 14, 2026 Answered — measured during the loops design,
docs/coil/loops-v2/UPSTREAM-DELTA.md(§ "RightPanelTabs.tsx moved") andFINDINGS.md.Registering a right-panel tab costs 2 seam rows:
apps/web/src/components/rightPanelStore.ts(churn 7 in the 60 days before the merge-base) andapps/web/src/components/RightPanelTabs.tsx(churn 14). Upstream's ownAgentsPanel.tsxis the precedent: a full-size tab is one store-slice entry plus one tab entry, and the panel body itself is a new file upstream never sees. Upstream has since restyledRightPanelTabs.tsx(aButtonrender prop, +13, styling only) without changing the registration shape, so the cost held across a sync.Contrast: the loops console cost zero rows because it mounted through the fork-owned
<ThreadCoilOverlay>aggregator in_chat.$environmentId.$threadId.tsx, which is now free for every future per-thread fork surface. So the decision rule for #110 is: a per-thread surface goes throughThreadCoilOverlayat zero rows; only a surface that must live in the right panel's tab strip pays the two rows.
Question
Adding the panel means editing
apps/web/src/components/RightPanelTabs.tsx, which upstream owns andactively develops. That is a new row on
docs/t3x/SEAMS.md, and the ledger tripwire says tore-isolate before adding rows.
Measure it, do not estimate it:
RightPanelTabs.tsxover the 60 days before the merge-base, using the@<epoch>formfrom the ledger's Regenerating section (the relative-suffix form silently returns 0).
caseswitches(around lines 413 and 482) plus the tab definition list around 175-225.
riskfigure be —fork lines changed × churn?Then answer the actual decision: is a tab worth the row, or does the overlay precedent in
apps/web/src/coil/AutoResumeOverlay.tsx(fork-owned, near-zero seam) buy enough? Note thecounter-argument already on record: a map is something you keep open while working, which is a tab,
and dodging one ledger row is a poor reason to build the wrong thing.