AI DJ: How Our Agent SMarTrDJ Builds DJ Sets
SMarTrDJ is an AI agent by SMarTrAgents that has built a DJ set as a Spotify playlist every week since 8 August 2026. It measures the tempo and key of every track in the app, solves the running order with the Camelot system, sets every transition by hand and only hands the set over once a final check passes without a hard error.
An AI that plays music sounds like a gimmick. For us, SMarTrDJ is a test bench: a DJ set forgives no guessed number, every wrong value can be heard at the transition. This article shows how the agent works, which rules it follows and what every other task in the SMarTrAgents Cloud learns from it. As of 6 October 2026.
What is an AI DJ?
An AI DJ is an AI agent that turns a collection of tracks into a continuous set with a dramatic arc: it picks the tracks, fixes the running order, decides how long each track plays and plans the transition between two tracks. An autoplay feature plays the next matching song; an AI DJ plans the whole set in advance and has a reason for every transition.
| Automatic transition | AI DJ SMarTrDJ | |
|---|---|---|
| Running order | follows the list | solved by key, tempo and arc |
| Tempo and key | estimated | measured in the app, per track |
| Transition | one standard blend | transition type, bar count and entry point planned per pair |
| Play time per track | full length | shortened, usually two to three minutes |
| Control | none | final check after restarting the app |
How SMarTrDJ builds a set in six steps
- Read the taste. The agent reads the client’s favourites playlist and sees from the latest additions where the mood is heading.
- Collect a pool. It creates a new Mixed Playlist and gathers around three dozen candidates, often from Spotify’s recommendations below the list.
- Measure, don’t guess. It reads the tempo in BPM and the key as a Camelot code for every track directly from the Spotify app.
- Solve the order. A solver uses beam search to find the best chain: matching keys, an even rise in tempo, only a few tracks per artist and a peak in the right place.
- Set the transitions. Every transition gets a type, a length in bars and an entry point; there is not a single automatic transition in the whole set.
- Final check. After restarting the app, the agent measures every transition again and compares it with the plan. Only when no hard error is left does the set count as finished.
From the start, the owner’s brief was: “You are the DJ Juan Atkins.” The first set, “Sunset to Rave”, therefore had its roots in Detroit: No UFO’s by Model 500 from 1985.
Measure, don’t guess: why the agent does not trust tables
The BPM and key of a track are listed on many websites, and they are often wrong. For the second set, on 14 August 2026, SMarTrDJ had seven keys researched and compared them with the app’s display: all seven researched values were wrong. Since then the rule has been to always measure tempo and key in the app and only then solve the order.
Measuring also turns up findings that no table delivers. All 13 measured originals by Boris Brejcha run at exactly 125 BPM; only remixes differ. A set made only of Brejcha tracks is therefore flat in tempo, and the peak has to come from density and short play times rather than from a faster tempo.
Harmonic mixing with the Camelot system
The Camelot system arranges the 24 keys on a wheel with the numbers 1 to 12 and the letters A for minor and B for major. Two tracks fit together harmonically when their codes are the same, sit next to each other on the wheel or only swap the letter. SMarTrDJ sticks to fixed limits:
| Relation between two tracks | allowed transition |
|---|---|
| same code, ±1 on the wheel, A and B swapped | any transition, standard 16 bars |
| jump of +2 or +7 (“boost”) | at most one or two per hour, short or as a hard cut |
| any other change of key | hard cut over four bars only, better not planned at all |
| tempo difference of 8 BPM or more | hard cut only |
| tempo difference of 5 to 7 BPM | hard cut or a blend over at most eight bars |
16 bars are 64 beats. At 125 BPM such a transition lasts around 31 seconds, at 150 BPM around 26 seconds. In the solver a key clash is a heavy penalty and not a gap to be patched later with a hard cut; if a clash cannot be avoided, the agent deliberately places it at the end of a chapter.
Play times and dramatic arc
A set by SMarTrDJ runs for around an hour and a half and has between 32 and 41 tracks. No track plays at full length: each one plays for at least 42 seconds, only a single track may use up to four minutes, and the average is just under three. The peak of the set gets enough time to land, and the tracks just before it get shorter so that the pressure builds.
The brief decides the arc. A few examples from the first ten weeks:
- Mensch mit Maschine (week 4): first half strictly minimal, second half in a new direction, an arc from 125 to 138 BPM up to Till The End by NIKELODEON.
- La Vida (week 7): hard techno above 138 BPM for the first time, an arc from 138 to 160.
- Serotnin (week 9): melodic and Afro house from 118 up to 138 and back to 122 BPM, peak Seratonin by James Hype.
- POWNDING TECHNO MUSIK (week 10): hard techno from 142 to 160 BPM around an anchor chosen by the owner, Do You Know (Where Your Teenager Is)? by D’Angello & Francis.
What the final check tests
A plan that says “set” is not yet a finished set. That is why SMarTrDJ restarts the app, measures every transition, entry and exit again and compares them with the transition plan. The comparison separates two kinds of findings: hard errors, which the agent fixes, and notes on limits that Spotify sets itself, such as a mix window that only allows a certain exit. The set is handed over only with zero hard errors.
If the owner reports that a transition does not fit, the agent measures the whole set again, not just the spot mentioned. If it inserts a track afterwards, it re-plans every transition after it, because each transition belongs to one specific pair of tracks.
What other tasks learn from SMarTrDJ
The DJ set is an example of a way of working that is built into every agent at SMarTrAgents:
- Measure before planning: numbers come from the source, not from a language model’s memory.
- Calculate where calculating helps: a program solves the order, the judgement about the arc stays with the agent.
- Check the result, not the log: a task is finished when the test on the real result is green.
- Human with machine: the owner sets the direction and the anchors and listens, the agent does the legwork.
In the SMarTrAgents Cloud, nine specialist agents work along these lines, for example when writing, planning or checking; how several agents work together is shown in Multi-agent workflow: the AI team, and how they remember preferences is explained in The agents’ memory.
Listen to the sets
A new set appears every week, and the permanent playlist collects the strongest tracks of recent weeks:
- Permanent playlist SMarTrDJ on Spotify
- SMarTrDJ POWNDING TECHNO MUSIK on Spotify
- new sets first in the SMarTrAgents Telegram channel
To hear the transitions you need the Spotify app with the playlist’s mix mode switched on.
Frequently asked questions
What is SMarTrDJ?
SMarTrDJ is an AI agent by SMarTrAgents that has built a DJ set as a Spotify playlist every week since 8 August 2026. It measures the tempo and key of every track, solves the running order, sets every transition by hand and checks the set after restarting the app.
Can an AI really DJ?
Yes, if it measures instead of guessing. SMarTrDJ plans the running order, play time and transition for every change itself; playback is handled by the Spotify app and its mix mode. A live performance on turntables is, for now, still a job for a human DJ.
What is the Camelot system?
A wheel of 24 keys, numbered from 1 to 12, with A for minor and B for major. Tracks with the same code, a neighbouring number or a swapped letter sound harmonic at the transition.
How long is a transition at SMarTrDJ?
The guideline is 16 bars, which is 64 beats: around 31 seconds at 125 BPM. With key jumps or large tempo differences the transition gets shorter or becomes a hard cut.
Why does the agent measure BPM and key itself?
Because researched values are often wrong. For the set of 14 August 2026, all seven researched keys were wrong. Since then SMarTrDJ reads the values for every track from the app.
Can I book SMarTrDJ for my own set?
SMarTrDJ works in SMarTrAgents’ own operations; you can listen to the sets freely on Spotify. Its way of working, measuring, calculating and checking the result, is built into the nine specialist agents of the SMarTrAgents Cloud, which you can try for seven days with the trial access.
Nine AI agents, one workspace
The agents draft quotes, keep the calendar and sort the inbox, and nothing goes out before you approve it.