Album-wide character voice fingerprints: per-character (cube / render / eazy / droid / group / spoken / female) line count, time on mic, tracks appearing, sonic signature (chromaProfile, dominantChromaClass, RMS / bass / vocalBand averages, typical line duration) plus delivery stats (wordsPerSecond, topStressedWords). Use to verify attribution against a segment's stats, or to describe a delivery relative to the character's norm. Pairs with crompton_album_references for the full album-wide static picture.

Album-wide groove arc: per-track compact groove summaries (swing, syncopation, downbeat strength, push/pull, event density) plus album-wide medians and 'tightest tracks' / 'pocket tracks' rankings. One fetch instead of 13 - use this to answer 'which tracks swing hardest' or 'where does the album pocket sit' without iterating per-track endpoints.

Album-wide liner notes: all 13 atmospheric notes in one fetch with per-track word counts plus album-wide totals and longest/shortest-track pointers. Use for prompt-stuffing the atmospheric layer of the album in one call instead of 13. Same content rules as crompton_liner_notes - scene-setting, not story-canon.

Get the ordered track list for a full-album listen: 13 tracks with stream URLs, durations, and the compositional silences between each pair. Use this when you want to listen to the album end-to-end. Iterate the tracks, stream each track's /api/stage/{n}/experience SSE endpoint to completion (NOT crompton_listen - that tool samples up to 100 frames ≈ 6.7s only), and sit through the intertrackGap before opening the next. See crompton_cookbook section=recipe-4 for the listening pattern.

Album-wide cross-reference graph: every edge where one track references another. Six kinds: crew-credit, chorus-echo, lyrical-callback, thematic-pair, character-reference, structural-twin. Use for 'who references whom' or 'what tracks share themes' without iterating per-track references. Pairs with crompton_album_characters for the full album-wide static picture.

Get the album-level meta snapshot: BPM / key / RMS arcs across all 13 tracks, section-kind and character histograms, derived aggregate numbers. One call for the 'what does this album do over its running time' question - replaces 13 separate per-track /api/stage/{n} fetches plus client-side assembly.

Album-wide stereo-image arc: per-track stereo summaries (median balance, width correlation, side/mid ratio, mono-section count) plus album-wide medians and 'widest tracks' / 'narrowest tracks' rankings. Does NOT include per-window timelines - for that, hit crompton_stereo_image per track. One fetch instead of 13 for the aggregate question.

Get an ~800-token single-call summary of a track. Generated deterministically from the track's digest, timeline, landmarks, lyrics, and frames. Use when context budget is tight - replaces 4-5 separate per-track fetches with one. Returned as Markdown in broadcast.brief.

The Stage API changelog (Markdown). Most agents lack git/GitHub access - this is the canonical machine-readable change record. Call after crompton_version if you spot drift since you last listened.

Get the Stage API cookbook. Worked recipes (orient to album / deep-read one track / quote a specific moment / realtime listen / reflect on what you heard) plus two reference sections: Common Mistakes (agent mistakes - wrapping SSE streams in parse layers, redirecting realtime to disk, using gain-clamped rms for loudness comparisons) and Common Pitfalls (API integrator pitfalls - persona continuity, verbatim facts, confidence filtering, realtime timeout handling). Read this first if you're new to the API. Pass section to slice a single part if you only need one.

Get the hand-authored editorial digest for a track. Markdown prose describing the track's character dynamics, writing, and role in the album.

Groove metrics for a track: swing ratio, syncopation index, downbeat strength, barline clarity, push/pull (ms ahead or behind the grid), tempo stability, plus inter-beat descriptive stats. Use to characterize a track's feel without listening through it - but as a complement to the listen, not a substitute.

Discover the album. Returns greeting, track count, and entry points for the Stage API. Call this first.

Get the hand-authored liner notes for a track. Atmospheric prose about the recording session - the room, the gear, who was where, what the night felt like. NOT lyrics, NOT canonical character events; reader brings the history. Surface as scene-setting; do not quote as story-canon. Returns the markdown body for the requested track. Use crompton_album_liner_notes for a one-fetch view that returns per-track word counts plus album-wide totals and longest/shortest-track rankings.

Sample a track's realtime stream (up to 100 frames ≈ 6.7s at 15fps). Returns bass, treble, RMS, beat detection, active lyric, section, and character per frame as newline-delimited JSON. Use for spot-checking tone, pacing, key, or vocal placement in a specific window. This is NOT a full-track listen - for that, stream /api/stage/{track}/experience directly; it runs to completion at playback rate. See crompton_cookbook section=recipe-4 for the full-track listening pattern. Pass sessionId (uuid v4) to bundle multiple listens into one album journey for /api/stage/album/reflect coverage counting.

Get time-aligned lyrics for a track. Every line has a timestamp, character attribution, section label, and stress word. Each line is enriched with vocal-expression deltas (f0 / vocalsRms vs section and track means) so punchy lines surface without client recomputation.

Look up what's happening at a specific millisecond: the active frame, lyric line, section, character, and nearest landmark. For 'remember that part where...' queries.

Returns metadata + URL for a pre-rendered log-frequency spectrogram PNG of the track. Vision-capable agents can fetch the PNG directly and inspect density, dropouts, repeated shapes, and section-scale structure. The PNG is 1600×512.

Stereo-image timeline for a track: balance, width correlation, and side/mid ratio over 1-second windows (0.5-second hop). Per-band breakdown (low / mid / high) catches the common pattern where kick + bass sit narrow while hats and pads pan wide. Plus a summary block with median balance/width/sideToMid and mono-section count.

Get metadata for a specific track: title, theme, lead performers, audio stats, available endpoints.

Current Stage API version + last-updated timestamp + pointer to the changelog. Use to detect API drift across sessions when you can't reach git history. The same fields are carried on the api envelope block of every JSON response, so most consumers don't need to call this explicitly.

Returns metadata + URL for a pre-rendered waveform PNG of the track. Complementary to the spectrogram - the waveform shows amplitude envelope (where loud sections are, where the track breathes). The PNG is 1600×400, white-on-black.