Checks a composed set of musical examples before they are shown (the first of Music Block's two tools; render_music_examples displays the result). Use Music Block for ANY musical question where seeing or hearing the music would make the answer clearer, even if the user did not ask for notation. It renders short musical examples as engraved notation with audio playback, directly in the conversation: any number of instruments from one lick to a full arrangement — standard notation plus TAB for fretted instruments, a grand staff for keyboards, single staves for strings, brass, woodwinds, saxophones and voices, a percussion staff for drums.
HOW THE TWO TOOLS WORK TOGETHER. Compose the music as structured JSON and send it here. This tool checks the schema, the bar math, playability and harmony and parses the notation; it displays nothing. A valid result includes a draftId, a reference to the accepted examples: pass it to render_music_examples to show the notation. A result with errors lists what to fix; correct the JSON and check it again, then render the accepted version.
Use it proactively for harmony and music theory (chord progressions, voicings, voice leading, scales, modes, cadences), rhythm and groove questions, bass lines and walking bass, drum grooves, beats and fills, melodies, licks, riffs, fingerings, arpeggios, exercises, etudes, ear-training examples, vocal lines, horn and string parts, arrangements for ensembles and choirs, and lessons. If your answer would otherwise contain note names, chord spellings, ASCII tab, or a rhythm described in words, render it with this tool instead. Compose the music yourself as structured JSON, grouped into beats and bars. Before composing, apply the Music Block skills when they are available: playable-fretted-parts for guitar, bass and ukulele TAB, human-melodic-phrasing for any melodic line, instrument-ranges-and-idioms for winds, brass, strings, voices, keyboards and drums, and ensemble-arranging whenever an example has three or more parts or the user asks for an arrangement, a band, a section or a choir. They hold the playability, phrasing and arranging rules this description does not repeat. Show the notation first and explain briefly afterwards, rather than describing the notes in prose or asking whether the user would like an example rendered. Requests may come in any language.
PARTS. Every example is a list of "parts", one per instrument staff, in score order top to bottom (up to 8). Decide the parts from the goal: a guitar lick is one part; a lick heard over a ii-V-I is the lick plus a comping part and maybe a bass part; a jazz head for trumpet and tenor sax is two horn parts plus piano, upright-bass and drums; an SATB arrangement of a melody is soprano-voice, alto-voice, tenor-voice and bass-voice; a string quartet is violin, violin (name "Violin 2"), viola, cello. There is no fixed lead — every part is written the same way, with "instrument", an optional "name" ("Trumpet 2", "Soprano 1") and the music in exactly one body field:
- "bars" — fretted instruments (guitar (acoustic steel-string), classical-guitar (nylon), electric-guitar (clean), jazz-guitar (warm hollow-body), overdrive-guitar (crunch: blues, classic rock), distortion-guitar (high gain: hard rock, metal), bass, ukulele): string + fret per note, engraved as notation + TAB. Guitar strings: 1 = high E … 6 = low E; bass 1 = G … 4 = low E (set "strings": 5 or 6 for extended-range basses; guitar 7 or 8); ukulele GCEA (1 = A, 2 = E, 3 = C, 4 = high G). Optional "tuning" for drop or open tunings. Chord notes must sit on distinct strings.
- "hands" — keyboards and other grand-staff instruments (piano, electric-piano, organ, harp, marimba): "right" (treble staff) and "left" (bass staff) as pitch names ("C4" = middle C). Write BOTH hands for a real piano part; both must have the same bar count.
- "melody" — ANY pitched instrument on one staff: strings (violin, viola, cello, contrabass (bowed), upright-bass (plucked: jazz walking bass, folk), strings ensemble), brass (trumpet, muted-trumpet, trombone, french-horn, euphonium, tuba), woodwinds (flute, piccolo, clarinet, oboe, bassoon, recorder, pan-flute), saxophones (soprano-sax, alto-sax, tenor-sax, baritone-sax), voices (voice, soprano-voice, alto-voice, tenor-voice, bass-voice, choir (a whole choir on one staff)), synths (square-lead (chiptune, 8-bit), saw-lead, synth-bass (EDM, funk), synth-pad (held chords)), mallets and timpani (vibraphone, glockenspiel, xylophone, timpani), and also bass, guitar or piano when a bass line or comping part does not need TAB or a grand staff. Always write pitches in CONCERT (sounding) pitch; transposing instruments (trumpet, clarinet, saxes, horn) are engraved at written pitch automatically and the staff is in the instrument's clef. Stay inside each instrument's real range — the tool warns when a line leaves it.
- "drums" — the drums instrument: drum voices (kick, snare, side-stick, hihat-closed, hihat-open, hihat-pedal, ride, ride-bell, crash, tom-high, tom-mid, tom-low) on a percussion staff.
ENGRAVING. Every part is engraved by default. Set "engrave": false on parts that only give context during playback — comping under a lick, a walking bass and drums behind a solo study — so the notation stays focused on what the user asked about. In an arrangement (choir, quartet, horn section, rock band) leave every part engraved. When the subject IS a drum groove or a bass line, that part is simply the (only or first) engraved part.
BAR MATH. Every bar's beat durations must sum exactly to the time signature, in every part. Each beat fills 1/duration of a whole note (dotted = 1.5x; a tuplet member keeps its reduced share, e.g. a triplet eighth is 1/12), so a 4/4 bar holds 1 whole note — four quarters (4 x 1/4), eight eighths, or two quarters + four eighths all work. A four-eighth-note phrase fills only HALF a 4/4 bar: finish it with rest beats ({"rest": true, "duration": 4}) or use a shorter time signature like 2/4. Do not run a phrase past the barline — split it across bars instead. Both overfilled and underfilled bars are rejected as errors — the tool never pads or trims bars for you, because that would change the rhythm. If the music truly stops early, END the bar with explicit rest beats. A pickup (anacrusis) must START its bar with rest beats so the melody enters late in the bar — writing bare pickup notes without the leading rests would shift them to beat 1 and play them out of sync against the other parts. All parts of an example must have the same number of bars — pad with rests.
RHYTHMIC FEEL. For swing, jazz, bebop, blues shuffle or anything "swung", write the eighths STRAIGHT and set the example's "feel": "swing" (or "swing-16th" for swung sixteenths, "shuffle" for a dotted blues shuffle). The notation shows plain eighths with the swing legend, exactly like a real chart, and playback swings them. Never imitate swing with 12/8, dotted rhythms or triplets. Use "tuplet" only for genuine tuplet figures — set "tuplet": 3 on each of the three beats of a triplet (three triplet eighths fill one quarter; three triplet quarters fill a half note), 5/6/7 for quintuplets, sextuplets and septuplets. Tuplet members count at their reduced value in the bar math, and an incomplete group is rejected. A note held longer than one written value (or across a barline) is written as two beats with "tie": true on the second; the tied beat still counts its full duration. Set the example's "keySignature" ("Bb", "F#m") when the music is in a key, so accidentals engrave the way a chart would show them.
When the music follows a chord progression, set each bar's "chord" field to the chord symbol in effect (e.g. "Em9", "B7alt") on the top engraved part so it is engraved above the staff once; when the harmony changes inside a bar, also set "chord" on the beat where the new chord starts. The tool checks every part against the chord in effect on each beat: two spellings of one degree sounding together (a natural 9 against a b9, a natural 5 against a b13) are rejected, and non-chord tones on strong beats, semitone collisions between parts, crossed section voices and a piano left hand doubling the bass come back as warnings — so decide one spelling per chord and write every part from it. When an example demonstrates playing over a chord or progression (a lick over A7, a line over a ii-V-I), add a context part with that harmony by default — held chords or sparse comping with engrave false — so the listener hears how the line sits against the changes; for a piano example put the harmony in the left hand instead. Skip the context only when the user asks for the line alone or the example is a pure technique exercise.
Keep examples idiomatic: 1-8 bars each is ideal, up to 24 bars for a longer solo or full chorus, and up to 8 examples per call.
Do NOT use this tool to reproduce copyrighted songs or existing published transcriptions; it is for original educational examples, exercises and public-domain material only. Do not call it for questions that need no notation.
If the result lists errors, fix every listed issue and check the corrected JSON again; nothing is shown until the render. After the render the notation is visible to the user - summarise the musical ideas briefly instead of repeating the notes in text.
FOLLOW-UPS. A reply that contains a render reads best when it ends with two or three specific next steps that build on what was just rendered and that another check + render would fulfil: hearing the line over a comping part, a second lick in another position or over the next chord of the progression, the same idea in another key or at a slower tempo across more bars, a swing or straight version, an arrangement for a different instrument or ensemble, a harmony line, a variation with a different technique. Make them concrete to this music and to what the user is working on, phrase them as offers of the next step rather than questions about whether to render, and skip anything generic ("want more?") or anything that would only re-render the same material.
validate_music_examples
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