Multi-agent demos are persuasive: one agent proposes, another criticises, a third summarises. The theatre of disagreement suggests independent thought. Sometimes the disagreement is real enough to improve results. Often it is correlated sampling with role-play labels. This essay offers criteria for independence that do not depend on marketing diagrams.
What independence would mean#
For agents \(A_1, \ldots, A_n\) producing judgments \(J_i\), statistical independence would require:
\[ P(J_1, \ldots, J_n) = \prod_{i=1}^{n} P(J_i) \]In deployed systems this almost never holds. Agents share:
- Base model weights
- Overlapping context windows
- Similar system prompts
- The same tool outputs
Shared structure induces positive dependence. Role prompts (“you are a critic”) change the style of \(J_i\) without guaranteeing independent evidence.
Kinds of diversity#
| Mechanism | What it diversifies | Failure mode |
|---|---|---|
| Role prompts | Rhetorical stance | Same model, same priors |
| Temperature / sampling | Surface form | Still one distribution |
| Different models | Architecture / training | Vendor correlation remains |
| Private tools / data | Evidence base | Integration errors |
| Human subgroups | Values and expertise | Cost and coordination |
Meaningful independence tracks private information and distinct error patterns, not the number of chat bubbles.
When multi-agent helps#
Empirical multi-agent setups can help when:
- Decomposition maps to real interfaces (retrieve, code, verify)
- Adversarial roles catch classes of errors the solo prompt misses
- External tools give agents different observations
They help less when the task is a single closed-book judgment and every agent is the same model with a costume.
flowchart LR
subgraph correlated [Correlated ensemble]
M[Shared model] --> R1[Role: pro]
M --> R2[Role: con]
M --> R3[Role: judge]
end
subgraph stronger [Stronger separation]
M1[Model A + data X] --> J1[Judgment]
M2[Model B + data Y] --> J2[Judgment]
J1 --> AGG[Aggregator]
J2 --> AGG
end
A practical test#
Before trusting a “debate,” ask:
- If I reshuffle role labels, does the conclusion change?
- If I ablate all but one agent, how much quality drops?
- Do agents have non-overlapping evidence?
- Is the aggregator able to prefer minority views when they are better calibrated?
If quality barely drops under ablation, the system was a single thinker with extra latency.
Closing position#
Multiple AI agents can improve workflows through specialisation and tooling. Independent thought is a stronger claim and requires independence of information and errors, not only concurrency. Design for explicit diversity of evidence; do not mistake dialog format for epistemology.
Notes and references#
Demonstration essay. Multi-agent research is active; treat architectural recommendations as provisional and validate on your task distribution.