Player scope

What belongs in the playback package, and what has to stay upstream.

The host side of .deck — Web Audio playback for programs parsed by @spacedevin/deck.

Entry: src/index.tish

This package exists so that playback never enters the language package. The root AGENTS.md lists "Audio / Web Audio engines" as out of scope for @spacedevin/deck, and that stands: ../../src/ stays audio-free. Everything that rule excludes lives here.

In scope

AST → Song IR: defaults, clamps, range checks. The parser deliberately does none of this (docs/DECK_GRAMMAR.md: absent optional = null, "host policy, and hosts genuinely differ"), so this package is where step_vel becomes 100 and an out-of-range lock gets decided.
Registry boot (registerGeneratorIdAliases, dialects, highlight keywords) per docs/HOST.md
Web Audio: channel bus, master chain, generators/voices
Transport: lookahead scheduler, play / pause / stop / seek, loop caps
Offline render (OfflineAudioContext)
The <deck-player> custom element
Tests: Song IR snapshots, pure timing math, a recording fake AudioContext for voice schedules

Out of scope — do not add here

Grammar changes. A new body head, top-level statement, or token shape belongs in ../../src/ and its conformance corpus. If you need something the parser doesn't expose, fix it upstream — never re-tokenize .deck text here.
Conformance cases. ../../conformance/ is the cross-implementation parse contract; adding a case there forces every profile in profiles.json to declare its position. This package reads that corpus as test input and keeps its own fixtures for playback behaviour.
Session / co-DJ / ownership, DJ mixer crossfading, cue outputs, scratch platters — all dropped from the Deckard port on purpose.
Instrument catalogs beyond the generators listed below.

Generators

Ported from Deckard (tish-midi/src/generators/), which is the reference host. The port is source-level: those modules are already Tish and already pure (play*(ctx, bus, t, midi, vel, durSec, ch, bendSemis)), so a fidelity difference is a porting bug, not a design choice.

Tier	Generators	State
1	`gameBoyDmg`, `gbaDirectSound`, `basicOsc`	ported
2	the other node-graph voices (`chiptune`, `nes2a03`, `c64sid`, `ym2612`, `sn76489`, `spc700`, `noiseBurst`, `fmTone`, `pad`, `bell`, `drumSynth`, …)	not yet ported
3	`patch`, `matrixFm` — need the gen_block graph parsers + the sync worklet	not yet ported
—	`ttsVocal`, `meSpeakVocal`	excluded: Web Speech API / `mespeak` dependency

Anything unported falls back to basicOsc so a song still plays; unsupportedGenerators() reports what was substituted.

Why `element/` is not Tish

element/deck-player-element.js is hand-written JavaScript, shipped as authored. A custom element must be class X extends HTMLElement, and Tish has no class syntax — tish build parses the declaration as an identifier expression and emits JS that doesn't parse. Everything with behaviour stays in src/*.tish; that file is only the DOM shell around it. Don't try to move it back.

Notes for editors

Per-instance state only. Deckard keeps loop counters in module-level maps (deckfile/LoopState.tish); here they live on the player instance, because two <deck-player> elements can share a page.
The deck package's registries are process-wide singletons. Boot is idempotent and runs once.
The clock worklet is loaded from an inline Blob URL, not a file — consumers must not have to copy assets. Keep the setTimeout fallback for contexts where addModule fails.