DevTools console sink

Phase 91 – the "passive narration" half of the live-debug console.

ConsoleDevToolsSink is an IFuaranTelemetrySink that pretty-prints the telemetry beacons Fuaran already emits – op-apply outcomes, authorizer denials, render failures – as severity-tagged, grouped DevTools-console records as they fire. It is the push counterpart to Phase 90's window.__fuaran REPL (which is pull – you ask): together they make the typed layer's behaviour legible in the browser console with no panel or extension.

It introduces no new telemetry contract – it renders only the existing OpApplyTelemetry / DenyTelemetry / RenderFailureTelemetry records that already ship through IFuaranTelemetrySink, and never gates dispatch (FGP 5: a pure read-projection of the canonical stream).

Wiring

open Fuaran.UI.Telemetry.Default

// Dev default: narrate everything, at every severity, to stdout.
let sink = ConsoleDevToolsSink.create ()

// Quiet diagnostic build: only denials + render failures.
let quiet = ConsoleDevToolsSink.createWith ConsoleDevToolsOptions.denialsAndFailuresOnly

// Custom filter knobs.
let tuned =
    ConsoleDevToolsSink.createWith
        { ConsoleDevToolsOptions.defaults with
            MinSeverity = DevToolsLevel.Warn }

Register sink wherever the host installs its telemetry sink (the same seam ConsoleSink / InMemorySink use). Pair it with the Phase 90 REPL for a full in-page debug experience, and surface both in the fuaran-live Console tab (Phase 94).

Severity model

Record	Level
OpApplyTelemetry – Applied	Info
OpApplyTelemetry – any failure outcome	Warn
DenyTelemetry	Warn
RenderFailureTelemetry	Error

MinSeverity filters by this rank (Info < Warn < Error); the per-record-type Show* toggles filter by kind. A record is rendered only when its toggle is on and its level passes the floor.

Grouped browser rendering (the writer seam)

Output is written through an injectable IDevToolsConsoleWriter – one Group(level, header, rows) call per record. The default ConsoleDevToolsWriter renders to System.Console as a tagged header line plus indented key: value rows (and, under Fable's System.Console shim, lands at console.log).

A browser host that wants true collapsible console.group / console.table records injects its own writer and keeps the sink's record-to-format logic unchanged:

let sink =
    ConsoleDevToolsSink.createWithWriter (ConsoleDevToolsOptions.defaults, myBrowserGroupWriter)

This keeps Fuaran.UI.Telemetry.Default free of any Fable/browser dependency while leaving the grouped browser rendering pluggable – the intended injector is the fuaran-live Console tab (Phase 94). The sink writes only through this seam (no raw Console.* from the sink itself – FGP 4); the writer is best-effort, and a throwing writer never poisons the apply/dispatch path it observes.

Stability

Additive – a fourth sink alongside NoOp / InMemory / Console; no change to the IFuaranTelemetrySink contract. The window.__fuaran global and the grouped-console output format are debug-only surfaces and are not covered by the language tier's semver guarantees.

TypeScript mirror

A parity sink on the TS side is deferred – it is gated on a @fuaran-ui/* telemetry surface, which does not yet exist (the Wave 10 follow-up shipped op-stream / layout-observer / ai-tools, not a telemetry package). When a TS telemetry surface lands, the mirror ships with the identical record-to-format mapping so the console output is host-agnostic.