# Per-agent inference settings The swarm can set the model and reasoning effort each agent's turns run on, plus the models it may start subagents on and how many subagents it may run at once. A field you set wins over the agent's own value; a field you leave unset keeps the agent on its own value, so an agent you set nothing for runs as it does today. ## Setting them ```sh swarmctl agent inference set iris --model opus --effort high swarmctl agent inference get iris swarmctl agent inference clear iris ``` - `set` changes only the flags you pass; the other fields keep what's stored. A hive must declare the agent. - `--effort` is one of `low`, `medium`, `high`, `xhigh`, `max`. - `--subagent-models` takes a comma-separated list. It replaces the agent's `availableModels` as the models its subagent `start` and `continue` calls may name, read on each call ([`subagent.md`](../tools/subagent.md#which-models-a-subagent-may-run-on)). - You set the subagent cap, `max_subagents`, in the swarm UI's inference dialog; `set` has no flag for it and keeps the stored one. It's a whole number from 1 to 32; unset means no cap ([`subagent.md`](../tools/subagent.md#how-many-subagents-may-run-at-once)). - `get` shows each field, naming the unset ones (or says the swarm sets nothing for the agent), and then the model and effort the agent reports running on, each with where it comes from. - `clear` removes every field; the agent goes back to its own values. The full flag reference is [`swarmctl-cli.md`](../tools/swarmctl-cli.md). The swarm UI's agents page edits the same settings; see [UI](ui.md). The swarm is the only place to change an agent's model or effort at runtime: its web UI shows both but has no picker and no `/model` or `/effort` command. ## What an agent runs on `get` shows what the agent runs on next to what the swarm sets: ```text model: opus effort: (not set; the agent's own) subagent_models: (not set; the agent's own) max_subagents: (not set; no cap) running model: opus (swarm) running effort: medium (local_file) ``` Each running value names where it comes from: | source | meaning | | ------------ | -------------------------------------------------------------------------- | | `swarm` | the value set here | | `agent_nix` | `services.hyperhive.agent.model` or `effortLevel` in the agent's agent.nix | | `local_file` | a `hyperhive-model` or `hyperhive-effort` file in the agent's harness dir | | `default` | the harness's built-in default (`haiku`, `medium`) | When the agent starts without a swarm value, its agent.nix model wins over a `hyperhive-model` file, and a `hyperhive-effort` file wins over its agent.nix effort. These files come from runtime picks the agent's web UI no longer offers; the agent still reads them but never writes them, so a `local_file` value stays until the swarm sets that field or someone deletes the file. The agent reports these whenever they change, and again once a minute. swarm-controller keeps only what it has received since it started, so for up to a minute after a controller restart `get` shows `running: not reported…`. ## When an agent picks a change up Each agent reads its settings every 10 seconds and switches on the next read: its next turn runs on the new model or effort, and its web UI badge shows it. A turn already running keeps what it started with. - **Its own value is the one it runs without the swarm**: its agent.nix or a `hyperhive-model` / `hyperhive-effort` file. Setting a swarm value doesn't overwrite it. - **Clearing a field** (or the whole key) puts the agent back on its own value on the next read. - **After a restart**, the agent runs its own values until its first read of its settings succeeds.
Implementation The settings live in the `agent-inference` KV bucket, one key per agent, which swarm-controller alone writes: ```json { "model": "opus", "effort": "high", "subagent_models": ["haiku", "sonnet"], "max_subagents": 3 } ``` Every field is optional. The agent runs the same with `{}` as with no key; `GET` answers `"configured": null` for no key (or a cleared one) and `{}` for a stored value with no fields. A stored value the controller can't decode, such as one a newer build wrote, also answers `"configured": null`, with a warning in its log, until the next `PUT` replaces it. | method | path | body | | -------- | ------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `GET` | `/api/agents//inference` | —; answers `{"configured": , "effective": }` | | `PUT` | `/api/agents//inference` | the whole value, replacing the stored one; the controller refuses unknown fields, an unknown effort, or a model name with whitespace or a leading `-`, or a `max_subagents` outside 1 to 32 | | `DELETE` | `/api/agents//inference` | —; answers 204 | An agent's own queue credential grants it `$JS.API.DIRECT.GET.KV_agent-inference.$KV.agent-inference.`, the direct read of its own key, and nothing else in this bucket — the same shape as its schedule key ([`schedules.md`](schedules.md)). The harness (`hive-agent`'s `swarm_inference`) applies a set field to the in-memory model or effort without writing `hyperhive-model` or `hyperhive-effort`, which keep the agent's own value. The subagent daemon (`hive-subagent-mcp`'s `swarm_models`) reads `subagent_models` and `max_subagents` with the same direct get, under the same credential, on each `start` or `continue`. `effective` comes from the agent's turn-state header on `$SWARM.agent-state.` ([`README.md`](README.md)), which carries `model`, `effort`, `model_source` and `effort_source`. swarm-controller subscribes to every agent's header with the reader grant it already holds for the state relay and keeps the latest per agent in memory. A header without those fields, from an agent that doesn't report them, leaves `effective` `null`.