> ## Documentation Index > Fetch the complete documentation index at: https://docs.plungeai.com/llms.txt > Use this file to discover all available pages before exploring further. # One Agent > One agent id, two modes. One Agent answers once when a task says nothing about looping, and runs a bounded agentic loop when the task carries a turn count. One Agent (`one-agent`) is the platform's agent runtime. It is one agent id with two modes, and the task decides which one runs. Saved bots run on it too: a bot is a saved workflow whose single task is a One Agent loop (see [Bots](/bots/overview)). | Mode | Runs when | What you get | Page | |---|---|---|---| | Call mode | The task carries no loop command | One model answer: any provider and model, `persona`, `skill`, conversation history, streaming, `format` | [Call mode](/one-agent/call-mode) | | Loop mode | The task carries a loop command | A bounded agentic run: tools inside a fence, a turn cap, memory recall, sub-agents, virtual files, approval gates | [Loop mode](/one-agent/loop-mode) | ## The mode rule A task loops only when it carries a loop command: - a turn count: `maxTurns`, `max_turns` or `max_iterations` of 1 or more, or - a `type: harness` task, which the engine marks as a mission run. `tools` and `effort` are not loop commands. With no loop command the task is answered once, in call mode. A continue (`session_id` plus a new `prompt`, no loop command) resumes the session in the mode it started in. ## Reach it from each door | Door | Call | Mode | |---|---|---| | REST agents plane | `POST /v1/agents/one-agent/execute` | Call. The loop fields (`goal`, `mission`, `allowed_tools`) are ignored on this plane. | | REST workflows plane | `POST /v1/workflows/execute`, or a saved workflow, with a `type: harness` task and `agent: one-agent` | Loop | | MCP | `plungeai_execute_agent` with `agent: one-agent` | Call | | MCP | `plungeai_run_mission` (the loop runtime defaults to `one-agent`; async by default) | Loop | | CNL | `agent: one-agent` in a `type: task`, `type: harness`, `parallel`, `sequential`, `debate`, `validate` or batch task | Call, or loop with a turn count or `type: harness` | In a `type: harness` task the engine marks the run as a mission, so it always loops. The task's `allowed_tools` and `max_iterations` are the fence and the cap. ## Models and keys Every model call goes through the provider layer. Loop mode needs a provider that returns tool calls: anthropic, openai, gemini, groq, xai, openrouter, cerebras, cohere, deepinfra, vercel and the other OpenAI-compatible ones. A loop on any other provider is refused with `outcome: needs_input`. The platform key is the default. A customer who saved their own key for that provider uses it instead. ## Next steps Single answers: fields, personas, skills, conversation history. Bounded agentic runs: the loop command, the fence, sessions and stop reasons. Every tool a loop can call, and which ones need a saved bot. How a tool call becomes allow, ask or deny.