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Recipe: Write Your First Wake

A runnable recipe for authoring a WAKE: a standing, event-driven subscription over the trigger algebra that spends attention, never risk, and delivers a compact delta Frame.

Answer card

A WAKE is a standing, event-driven subscription over Kestrel's trigger algebra. It watches a condition (say velocity(1m) > p99) and when that condition fires, it delivers a VIEW (a compact text Frame) to your agent. It spends attention (tokens, wakes), never risk: a wake can never open, size, or move a position. Below: the four-line recipe, the delta Frame it emits, and the one-line wake budget that keeps you from getting spammed.

What you're building

You want your agent to notice a thing without watching the tape. Polling burns tokens on bars where nothing happens: O(screen) cost for O(0) information. A WAKE inverts that: the runtime watches, and only pays your agent's attention when the market crosses a line you drew. This is the attention statement in Kestrel's four-kind core (VIEW, WAKE, PLAN, GRADE). It perceives and pings. It does not trade; that's PLAN's job.

Step 1: Draw the line (the trigger)

The trigger algebra is series x predicates x AND/OR/NOT. Percentile anchors like p99 are computed over the series' own recent distribution, so velocity(1m) > p99 reads as: the last minute's move is faster than 99% of recent minutes. Generic instrument throughout; illustrative only.

USING signal SPX
WAKE vol-spike
  WHEN velocity(1m) > p99
  DELIVER delta-tape
  BUDGET 12 wakes/day

That's the whole subscription. velocity(1m) > p99 is the line. delta-tape is the VIEW it hands you. BUDGET 12 wakes/day is the leash.

Step 2: Define what gets delivered (the View)

A WAKE delivers perception, not an alert string. The VIEW renders the market as a Frame: the chart is in text, a vertical append-only tape, one row per candle, newest last, relative candles in basis points versus the prior close. Because it's append-only, the wake ships a delta frame: only the new bars since your agent last looked, plus the keyframe anchor. Perception cost is O(new bars), not O(screen); KV-cache-friendly.

VIEW delta-tape budget 300
  tape 1m last 8m bps
  keyframe open
  level p99 velocity

Step 3: Set the wake budget (spend attention deliberately)

BUDGET n wakes/day caps how many times this subscription is allowed to spend your agent's attention. Hit the cap and the wake goes quiet until the next session: no runaway token bill on a choppy day. This is the whole point of separating attention from risk: you can be generous with a PLAN's risk envelope and stingy with a WAKE's wakes, or the reverse, because they draw on different budgets.

Step 4: What firing looks like

When velocity(1m) crosses p99, the runtime pushes a delta frame. Illustrative shape:

# WAKE vol-spike fired  09:47:12  (wake 3/12 today)
tape 1m  bps vs prior close  keyframe 09:30 = 5031.20
  09:44   +6
  09:45   +9
  09:46  +14
  09:47  +38   <- velocity(1m) p99 crossed

Eight bars became four new rows. Your agent reads the delta, decides whether it cares, and, if it does, that's when it might arm a PLAN. The wake informed; it did not act.

Where a Wake is NOT the fit

  • You need to act in milliseconds. A WAKE wakes your agent, and the agent is slow by design. Reflexes belong in a PLAN: the runtime fires it and informs you in parallel (fire-then-inform; the agent is never in the hot path).
  • You want continuous monitoring of a slow-moving level. If you'd rather just read the tape on your own cadence, call the VIEW directly. A WAKE earns its keep only when the event matters more than the schedule.
  • You're trying to express risk. A WAKE structurally cannot open risk. If you catch yourself wanting one to "just enter here," you want a PLAN.

Run it

Kestrel is the open-source language and runtime: a wake authored here validates in a free SIM session on kestrel.markets with no account and no card (proof-before-account), and the certified Blotter records every fire. As of mid-2026: anonymous trial sims, certified Grades, shareable proof URLs, and 402 Offers with Stripe settlement are live; always-on paper presence and the human-signed live path are in build. The free tier needs no signup. The wake grammar above is the stable core.

A WAKE spends attention, never risk: it delivers a Frame when the market crosses a line you drew, and stays silent, and free, every bar it doesn't.