Music Prompter

Music Prompter

Turn a musical brief into a coherent prompt, an approved SandBase generation, or a verified multi-clip deliverable. Keep prompt writing useful without an external service, and use SandBase for every generative music call.

Read the SandBase API map before selecting or running a model.

Choose the delivery mode

• Prompt only: return a polished prompt, optional lyrics, and arrangement plan. Do not call a paid model.
• Generate one track: select and inspect a current SandBase music model, show the execution price and arguments, obtain confirmation, then generate.
• Produce a long or multi-part piece: plan the full arrangement, generate an approved set of clips, assemble them locally, and verify the result.

If the six sandbase_* MCP tools are unavailable, continue only in Prompt only mode. Point the user to the current setup instructions in the SandBase CLI repository; do not request a provider-specific API key or silently switch services.

Define the musical brief

Resolve only the choices that materially affect the result:

• purpose, audience, platform, and target duration;
• genre and stylistic era without imitating a living artist's identity;
• emotional arc, energy, tempo, meter, and harmonic character;
• core instrumentation, arrangement density, and sonic palette;
• instrumental or vocal, language, lyric ownership, and explicit-content limits;
• loopable ending, clean ending, fade, stems, or other delivery requirements;
• preferred file format, sample rate, and bitrate when the selected model supports them.

State reasonable assumptions for missing details. Treat lyrics, reference audio, and unpublished compositions as private user data and send only what the inspected endpoint needs.

Build the prompt

Describe the piece as one coherent production brief. Include the dimensions that matter rather than filling every field mechanically:

1. Global direction — intended duration, instrumental or vocal mode, language, tempo, and output purpose.
2. Genre and style — genre family, period, performance character, and relevant production tradition.
3. Rhythm and tempo — BPM or tempo range, meter, groove, swing, syncopation, and rhythmic intensity.
4. Harmony and tonality — key or tonal center, major/minor/modal color, chord density, and harmonic movement.
5. Mood and arc — starting emotion, development, peak, release, and ending state.
6. Instrumentation — lead, rhythm, bass, percussion, texture, and how layers enter or leave.
7. Density and brightness — sparse or dense arrangement, register, frequency emphasis, and dynamic range.
8. Space and ambience — room character, reverb, stereo width, distance, environmental texture, and intimacy.
9. Production quality — polished or raw, modern or vintage, clean or saturated, and mastering intent.

Use direct positive language first, followed by concise exclusions such as “instrumental only, no vocals” or “no drums or percussion.” Do not invent a negative_prompt field unless sandbase_inspect shows that the chosen endpoint supports it.

For precise arrangements, add chronological cues whose final timestamp matches the intended duration:

Instrumental only. Create a 60-second warm, introspective lo-fi cue at 80 BPM.

[0:00-0:12] Intro — solo electric piano, soft room tone, intensity 1/10.
[0:12-0:36] Development — relaxed drums, sub-bass, and a restrained synth motif, intensity 4/10.
[0:36-0:50] Peak — fuller harmony and wider stereo image, intensity 6/10.
[0:50-1:00] Outro — remove drums and resolve to a clean, spacious ending, intensity 2/10.

Timestamp cues are prompt content, not guaranteed controls. Disclose that timing, lyrics, and structure may vary unless the inspected model exposes explicit controls for them.

SandBase execution contract

For generation, follow this sequence:

1. Call sandbase_discover with a short capability query such as text to music, instrumental music, or music with lyrics.
2. Call sandbase_inspect for serious candidates. Compare the live schema, prompt and lyric limits, instrumental control, output formats, duration behavior, price, and sync or async execution mode.
3. Prefer the smallest number of calls that can satisfy the requested duration and structure. Do not assume a universal maximum track length from an earlier model.
4. Before the first paid call, show the selected endpoint, important arguments, per-call price, call count, and total estimate or uncertainty. Obtain confirmation for that exact call or batch.
5. For an approved batch of multiple calls, use sandbase_account to check the available balance.
6. Call sandbase_run with the exact discovered name and only arguments defined by the current inspection response.
7. If a run ID is returned, poll that same ID with sandbase_run_get until it completes or fails. Never create a replacement merely because a music run is still pending.
8. Use sandbase_runs only to recover a lost run or reconcile status and actual cost.

Do not hard-code a model, duration limit, price, schema, or output URL. Availability changes, and discovery plus inspection is the source of truth.