Drum machine · claude-haiku-5.5

I'm planning the audio scheduler design: using a lookahead loop with setTimeout polling, tracking note timing against the audio context clock, and queuing step events so the visual highlight stays in sync with playback.

For stopping playback, I need to track active audio nodes so I can call stop() on scheduled-but-not-yet-played sounds, add them to a set at creation and remove them on completion, and reset the step counter and timer cleanly.

Editing the grid during playback should only affect steps not yet scheduled, which works naturally given the short lookahead window, and I'm computing BPM-based timing by converting beats per minute into sixteenth-note durations.

I'm designing each percussion voice: kick as a sine oscillator sweeping down in pitch with a decaying gain envelope, snare combining filtered noise with a short tonal thump, hihat as high-passed noise with a quick decay, and clap as layered short noise bursts for a staccato effect, all built from a single shared white-noise buffer.

For the UI, I'm syncing the step highlight to actual playback time using a animation-frame loop that checks a queue of scheduled times, and setting up Play/Stop/Clear controls plus a BPM slider with a default drum pattern across the 16 steps.

I'm now writing the lookahead scheduler loop that keeps queuing upcoming steps slightly ahead of the audio clock using setTimeout, and figuring out how Stop should reset playback state and whether the step-0 indicator should remain visible while stopped.

I also work through tracking active audio nodes so Stop can safely cancel both playing and future-scheduled sources, handle grid rendering with toggleable step buttons via event delegation, and tie the BPM slider directly into the scheduler's timing so tempo changes apply live.

Checking the screenshot against my pattern, the kick, snare, hats, and clap positions all line up correctly with what I intended. The cue dot at step 1 also looks right.

I'm reviewing some edge cases around stop/start handling and the highlight cue state, but these seem fine given the try/catch safeguards. Given limited time, I'll do a quick manual verification instead: click the play button, let it run briefly, and take a screenshot to confirm the step highlight advances properly.

The playhead advances with the current step highlighted. Now I want to test the BPM change by dragging the slider toward 180, checking the sequencer state, then testing stop and start.

The BPM change confirmed the playhead moved correctly across steps at 180 BPM. Now I want to verify stop and play behavior by taking screenshots after clicking stop, then after clicking play again, keeping in mind that stop resets the cue to step 0 and cancels active nodes.

Stop correctly resets the playhead to step 1 while keeping the pattern intact, which is the right behavior. Now I'll click Play and take a screenshot to confirm it restarts properly from step 1.

The restart looks consistent since step 2 is highlighted in the second frame while the first frame has no highlight, matching the code's step=0 start, though I haven't directly verified step 1 plays first. I also want to double check the stop-cue dot behavior on step 1 against the first screenshot's highlight.

Checking through the rest of the logic — queue clearing on stop/start, node cleanup via onended, noise buffer timing, and the clap tail's connect/disconnect sequence — everything looks correct. The Space key handler and status display during stop also seem fine, though I can't verify actual audio output by ear.

I'll note the unverified items (audibility, timing precision, Space key behavior, Clear during playback) in my report since the file is already saved and no further edits are needed.