External Enrichment · Grid example

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Companion film

Live data in

Bring in a live FX rate, contain a failed ML signal with a deterministic fallback, and keep exposure recalculating.

19 secGrid 0.61.0

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What this model gives you

A fallback-safe enrichment flow whose raw FX and scoring work stays visible while decisions remain computable.

25 min to study · Source reviewed 2026-08-24

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What to notice

Eager and lazy work
Named external arguments
Raw result inspection
Explicit fallback policy

Requirements

Async worker runtime
Network for live FX
Configured scoring route for live ML_SCORE

Expected checkpoint

A known state for this walkthrough.

Before providers return, or after a terminal failure without a satisfactory cached value, using the canonical fallback constants.

Converted amount: 262,500C1 fallback path
Score: 0C2 fallback path
Decision: auto-approveC3 canonical policy
Cross-rate: 1.1905C4 fallback path

01 · Request

Raw provider work stays inspectable

FX_RATE starts eagerly while ML_SCORE remains lazy until a dependent asks for it.

02 · Protect

Fallback policy belongs downstream

DEFAULT keeps calculations available without replacing the raw binding or hiding its external status.

03 · Isolate

Only changed arguments invalidate work

A new amount recomputes conversion locally; a changed feature vector invalidates only the scoring branch.

04-external-enrichment.grid

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MODEL "External Enrichment"
DESCRIPTION "Portable model that delegates async work to external workers."
VERSION "1.0.0"
AUTHOR "Grid Team"
TAGS "canonical", "portable", "external", "async"

# Inputs
A1 IS currency = 250000
A2 IS percentage = 18pct
A3 = 0.12
A4 = 0.18
A5 = 0.27
A6 = 0.43
A7 = "EUR"
A8 = "USD"

# External signals
B1 = FX_RATE(A7 AS base, A8 AS quote)
B2 ~= ML_SCORE(A3:A6)
B3 = FX_RATE("GBP", "USD")

# Fallback-safe analytics
C1 IS currency = ROUND(A1 * (B1 DEFAULT 1.05), 2)
C2 = B2 DEFAULT 0
C3 = C2 > 0.35 THEN "manual-review" ELSE "auto-approve"
C4 = ROUND((B3 DEFAULT 1.25) / (B1 DEFAULT 1.05), 4)
C5 = `eur_usd={B1 DEFAULT 1.05} score={C2}`

END MODEL