The Pair Desk

A pairs trade is two instruments flown as one — and most terminals make you fly it on two detached screens, hand-balancing legs in your head. The Pair Desk at /pairs is one page per pair: the spread — the thing you actually own — front and centre, both legs instrumented beside it, your book state folded into the page, and every control priced in the only unit that matters (achieved z, edge erosion).

The page opens on the day's best eligible pair (or the last pair you worked) and deep-links as /pairs/PAIR. Reach it from the "TRADE THIS PAIR" button (the ∞ mark) anywhere it appears, from a TRADE → on a watch or position row in your Book, or from a sphere in HyperZone's pairs field.

The roster is a keystroke

Press / (or click the pair name in the header) to open the switcher: the daily roster of statistically eligible pairs as a mini table — score, live z, state, band levels — with filters for tracked pairs, book status, live-z stretch, and venue. The roster is refreshed once per day and ticks live against that day's locked statistics. Pick a row to fly that pair.

Which recipe you're working

The desk resolves the recipe the same way the rest of the terminal does, and the header chip always says which:

• Open position → the locked snapshot from entry (β, μ, σ, bands as they were the day you entered), immune to daily refits.
• Watching / not in book → today's plan-of-date recipe, which floats with the daily refit.

See Watching & Tracking for why this distinction exists.

The layout

The desk is viewport-locked on desktop — the page never scrolls; panels scroll internally. Reading order is flight order: verdict → horizon → engines → traffic → controls.

• Left rail — account, feed diagnostics (silent when green), the day's plan at a glance (run date, pair count, tracked results, next-refit countdown), a deep-quant pop-out, and the pop-out launchers for each leg's Liquidity Terrain.
• Header — one line: legs, state, the recipe chip, provenance.
• The hero — BUY SPREAD / SELL SPREAD, lit only while live z is genuinely outside that side's entry band, with a violet chip naming the plan the verdict comes from. Beside it, the trade card: plan target in spread %, typical hold, stop distance, and the strategy's hit rate on this pair — every number plan-derived and labelled. The hero is stateful: in a position it shows your spread P&L since entry, entry z versus now, and days on versus usual — and can arm the exit plan; with a resting trade armed it shows what's resting and where, with amend and cancel; flat, its ARM ticket arms a resting entry that fires when the band crosses.
• Spread chart — the artificial horizon: tall, centre, 15m / 1h / 4h / 1d buckets with a RE-CENTRE control. The spread series is 1m-sampled closes bucketed to OHLC — tick-level spread OHLC is unknowable, and the caption says so. The chart flips to a Pair Details face: half-life, spread σ, lookback, and the fit-window backtest.
• Leg charts — both engines under the horizon behind a raiser, the hedge leg labelled with its β weight.
• The cloud — a strip of the day's top eligible pairs over a reduced 3D field of the whole roster; the current pair is haloed. Click a chip or a sphere to switch.
• Traffic column — dual depth with the σ-priced spread ladder on top, the merged tape below. What's resting and what's printing are one glance-group.
• Console drawer — docked at the bottom edge: the Launcher (pair mode), Track controls, the locked plan, eligibility, funding, the algo Playbook, Blotter, and Account.
• Book rail — right edge, collapsed by default: your positions first (each with live spread P&L), then armed and watched pairs, then the eligible roster by score, each row ticking live z. It also expands into the full screener — the whole eligible universe as a sortable table with checkbox bulk-watch. The Book page remains the aggregated view for monitoring and updating everything standing across pairs.

The σ-priced spread ladder

The desk's signature widget. For a series of clip sizes it walks both legs' order books simultaneously, β-weighted, and prices each tier not in dollars but in achieved z — the z-score you would actually lock in after eating both books' depth:

• Achieved z — the effective spread level your fills would establish, per clip size.
• Erosion (σ) — how much of the statistical edge each tier gives back to market impact, versus the on-screen tape z. Edge erosion is the honest cost of size in a mean-reversion trade.
• "> visible book" — tiers beyond the thinner leg's visible depth are flagged per leg, not extrapolated.

Fill balance

A pair position only hedges if both legs actually fill in ratio. The desk shows, per β-weighted leg, what fraction of a clip the visible book can absorb, and flags when the ratio between legs leaves the acceptable band — the thin leg is named. This is the pre-flight for two-leg execution: if one leg can't keep up, you're not putting on a spread, you're putting on a directional position with extra steps.

Merged tape

Both legs' prints in one leg-tagged tape, with per-leg 60-second aggressor skew bars and per-leg suspected-TWAP chips — if someone is already working one of your legs, you want to know before you join them.

The Launcher in pair mode

The console's Launcher understands it is standing on a two-leg desk:

• Single-leg algos (IOC, TWAP, Iceberg, Chase, Scale, stops…) are greyed with the reason and an exit: single-leg — work it on that coin's own desk →.
• Pair-native algos (Autospreader, PairGlide) take a clip and pre-flight it against both live books: tape z versus achieved z, edge erosion in σ, and the fill-balance verdict — every number book-derived, nothing extrapolated. The hero's buttons open the Launcher pre-filled with side and a clip size chosen by walking the ladder.

Honesty rules

• A pair whose daily statistics could not be fit is suspended, not silently shown with stale numbers.
• Stale data never looks live — the hero's zones suspend and chips amber when a plan or feed degrades.
• Dollar P&L appears only once fills carry a size; until then the page shows spread % and says why.

What arms from here

The pair-native algos arm live from this desk — Arm posts to the engine and it works both legs for real, signed by the order-only agent your wallet approved. The hero's ARM ticket arms resting entries and exit plans the same way. Single-leg algos stay greyed with the reason and an exit to that coin's own desk, and nothing on the page looks armable unless it is.