Render music notation from a JSON score. Returns inline SVG, MusicXML, and MIDI in one call. Use scientific pitches ("C4", "F#5", "Bb3") and duration codes (w h q 8 16 32 64 with optional dots). Bar lines are inferred from the time signature; notes that cross bar lines are split and tied automatically. Call notation_validate first if you are unsure your input is well-formed — validate is cheaper than render.

Pre-flight validate an input shape without rendering. Returns errors with concrete fix suggestions when input is malformed. Cheaper than notation_render — use this when iterating on input shape.

Search the Gradus music-theory knowledge base for authoritative source material. The corpus includes hand-authored curriculum prose, Bach chorale analysis (408 chorales), score commentaries on 50+ orchestral works, and primary historical sources from Fux (1725) through Boulanger.

WHEN TO USE: before generating notation if you need to look up a specific theory fact — typical voice leading for a Neapolitan-to-V resolution, idiomatic figured-bass realizations of a particular cadence, what makes a chromatic mediant feel like one composer's style versus another. Hitting this first prevents the agent from inventing chord progressions that are stylistically wrong.

WHEN NOT TO USE: for generic music vocabulary ("what is a chord?") that any LLM already knows; for non-theory queries like composer biographies, performance recommendations, or history dates — those are out of scope; for fetching actual score notation (use notation_render or notation_examples instead).

INPUT: provide EITHER topics (kebab-case tags) OR step (curriculum step 1-49). Topics are stronger; step is the fallback when you do not know the canonical topic tag. Both empty returns a MISSING_QUERY error.

OUTPUT (JSON): { ok: true, requestId, chunks: [{ id, sourceType, sourceId, title, content, composer?, era?, topics: string[], curriculumSteps: number[], tokenEstimate }], meta: { query, returnedCount, totalTokens, responseTimeMs }, attribution }. sourceType is one of: kg_concept, score_analysis, score_commentary, bach_chorale_analysis, composer, dictionary, curriculum, lesson_content, practicum, voice_leading, fugue, chorale_exercise, etc. Empty chunks: [] when nothing matched the topics — agent should fall back to its own knowledge or try a different topic tag.

EXAMPLE INPUT: { "topics": ["voice-leading", "deceptive-cadence"], "limit": 3 } TYPICAL LATENCY: 200-700 ms (one Voyage 3 embedding call + Supabase pgvector RPC).

Fetch canonical example inputs (single melody, two-voice counterpoint, chord progression, mixed rhythms with dynamics, string quartet snippet, tied notes across bar lines). Cache the result client-side; the response shape is stable.

Fetch the JSON Schema for the notation_render input shape. Cache the result client-side; this is stable across the v1 API.