Mixture of Agents

Mixture of Agents is a virtual model provider. Each named MoA preset appears as a selectable model under the moa provider.

When you select a MoA preset, the preset's aggregator is the acting model. It is the model that writes the assistant response and emits tool calls. Reference models run first and provide analysis for the aggregator to use.

Use MoA when a hard task benefits from multiple model perspectives but still needs Hermes' normal agent loop: tool calls, follow-up iterations, interrupts, transcript persistence, and the same session context as any other message.

Select a MoA preset as your model

You can select a preset through the normal model picker surfaces:

/model default --provider moa
/model review --provider moa

MoA presets are selectable on every Hermes surface, because MoA is a normal provider in the model system:

• CLI / gateway / TUI /model — /model <preset> --provider moa, or /model --provider moa for the default preset. A bare /model <preset> also works when the name exactly matches a configured preset.
• hermes model and the Dashboard model picker — a Mixture of Agents provider row appears with your preset names as its models.
• Desktop GUI app — the model dropdown shows an MoA presets section; selecting one (MoA: <preset>) switches the active model to that preset. The Desktop settings panel also creates and edits presets.

Configured presets therefore show up wherever you would pick any other model.

Slash command shortcut

/moa is one-shot convenience sugar. It runs a single prompt through the default MoA preset, then restores whatever model you were on:

/moa design and implement a migration plan for this flaky test cluster

Hermes temporarily switches to the default MoA preset for that one turn, sends the prompt, then restores your previous model afterward. The whole argument is the prompt — /moa no longer interprets it as a preset name.

/moa

Bare /moa (no prompt) just prints usage.

To switch to a MoA preset for the rest of the session, select it from the model picker — MoA presets appear under a Mixture of Agents provider in every model-selection surface (see above). /moa is deliberately not a model switch, so a normal prompt can never accidentally change your model.

How it works in the agent loop

For each main model call when provider moa is selected, Hermes:

1. resolves the selected preset by name;
2. runs the configured reference models without tool schemas (they receive only the conversation's user/assistant text — not the Hermes system prompt or tool-call transcript — so reference calls stay cheap and avoid strict-provider rejections);
3. appends the reference outputs as private context for the aggregator;
4. calls the configured aggregator with the normal Hermes tool schema;
5. treats the aggregator response as the real model response;
6. if the aggregator calls tools, Hermes executes those tools normally;
7. on the next model iteration, the same MoA process runs again over the updated conversation, including tool results.

Because MoA is selected through the normal model system, it composes automatically with /goal, gateway sessions, TUI sessions, and Desktop chat.

Configure presets

You can configure named MoA presets from:

• Dashboard → Models → Model Settings → Mixture of Agents
• Desktop app → Settings → Model → Mixture of Agents
• hermes moa configure [name]
• config.yaml

The config stores explicit provider/model pairs, so you can mix providers and use multiple models from the same provider:

moa:
  default_preset: default
  presets:
    default:
      reference_models:
        - provider: openai-codex
          model: gpt-5.5
        - provider: openrouter
          model: deepseek/deepseek-v4-pro
      aggregator:
        provider: openrouter
        model: anthropic/claude-opus-4.8
      reference_temperature: 0.6
      aggregator_temperature: 0.4
      max_tokens: 4096
      enabled: true

Default preset:

• reference: openai-codex:gpt-5.5
• reference: openrouter:deepseek/deepseek-v4-pro
• aggregator / acting model: openrouter:anthropic/claude-opus-4.8

Terminal preset management

hermes moa list
hermes moa configure              # update the default preset
hermes moa configure review       # create or update a named preset
hermes moa delete review

Benchmarks

On HermesBench, a two-model MoA preset — claude-opus-4.8 aggregating over a gpt-5.5 reference — outscores either model run on its own:

The MoA configuration beats its strongest component (opus-4.8) by ~6 points, confirming that aggregating a second perspective lifts quality on hard tasks rather than just averaging the two.

Prompt caching

MoA is built so the main conversation's prompt cache is never broken. Selecting a MoA preset is a normal model selection: it does not mutate past context, swap toolsets, or rebuild the system prompt mid-conversation. Your conversation history, system prompt, and tool schema stay byte-stable, so the cached prefix every other model relies on is preserved exactly as it would be for a plain model. Switching to or away from a MoA preset costs the same cache invalidation as any other /model switch — no more.

Both internal call types cache normally:

• Reference models receive a trimmed, deterministic view of the conversation (system prompt and tool transcript stripped — see the loop above). Because that view is a stable function of the stable history, a reference model's prompt prefix repeats across iterations and caches normally. References are short advisory calls with no tools.
• The aggregator is the acting model. The reference outputs are appended to the end of the latest user turn as private guidance. Because that text sits at the tail — below the entire stable prefix (system prompt + prior history) — it does not invalidate any cached prefix: the aggregator gets a cache hit on everything above the injection, and only the freshly appended tail is new. That is exactly how every normal turn behaves, where each new user message is also uncached tail tokens.

So MoA does not sacrifice prompt caching on either call type. Its only real cost is the extra reference calls per iteration — you pay for multiple model perspectives, not for broken caches. The long-lived conversation prefix shared with the rest of Hermes is fully intact.

Notes

• MoA is no longer listed under hermes tools; there is no moa toolset to enable.
• Setting enabled: false on a preset disables the reference fan-out for that preset: the aggregator acts alone, exactly as if you selected it as a plain model. This is the per-preset off switch surfaced in the dashboard and desktop settings.
• A preset's aggregator cannot be another MoA preset. Recursive MoA trees are intentionally blocked.
• Credential failures on one reference model do not abort the turn. Hermes includes the failure in the reference context and continues with whatever models returned.
• MoA increases model-call count. A single model iteration can involve multiple reference calls plus the aggregator call.