Modes & Models

Amp uses different models for different kinds of work. The main agent handles your task, specialist subagents take on focused parts of it, and smaller system models handle supporting jobs.

The Modes & Models page shows the current model routing. The models can change as better options become available, while the role of each mode and subagent stays stable.

Modes

The Dial gives you four built-in modes: low, medium, high, and ultra. Each mode combines a model, reasoning effort, system prompt, tools, and oracle for a particular level of difficulty.

Choose a mode based on the task rather than the model name. See The Dial for help choosing one.

Specialist Subagents

Amp can delegate focused work to specialist subagents. Each subagent has its own context window and access to tools like file editing and terminal commands.

  • Review identifies bugs and reviews code changes.
  • Search retrieves relevant code quickly.
  • Oracle handles difficult reasoning and planning questions.
  • Librarian researches external codebases and large bodies of source material.
  • Read Thread reads and summarizes other Amp threads.

Subagents are most useful for multi-step tasks that can be broken into independent parts, operations producing extensive output not needed after completion, parallel work across different code areas, and keeping the main thread’s context clean while coordinating complex work.

Amp chooses subagents automatically for suitable tasks, mostly in medium mode but occasionally in other modes. You can also ask Amp to use a subagent or to split independent work across several subagents. They work in isolation, so they can’t communicate with each other, you can’t guide them mid-task, and they start with the instructions and context the main agent gives them rather than the full conversation. The main agent only receives their final summary rather than monitoring their step-by-step work.

System Models

Supporting models handle jobs that do not need the main agent. These include analyzing images, PDFs, audio, and video; generating or editing images; naming threads; and compacting the context of long conversations.

This routing lets Amp use a frontier model where deep reasoning matters and a faster specialist where speed matters more.

Custom Agents

Plugins can define custom modes and custom subagents. A custom mode appears in the mode picker. A custom subagent can be exposed as a tool that the main agent calls for a specific kind of work.

See Define a Custom Agent Mode and Define a Custom Subagent for examples.

Enable Claude Fable 5 With BYOK

Anthropic requires data retention for Claude Fable 5. If you use your own Anthropic API key with Amp, enable data retention for the workspace that owns the key:

  1. Sign in to the Claude Console as an organization admin.
  2. Go to Settings > Workspaces. Create a workspace for Fable workloads, which keeps them separate from other workloads, or select an existing workspace to convert.
  3. Open the workspace and go to Manage > Privacy controls.
  4. In Data retention, turn on data retention for the workspace.
  5. Review the confirmation dialog and select Accept. Anthropic records who accepted the change and when. Data retention takes effect for the workspace immediately.
  6. Assign the users who need Claude Fable 5 to this workspace.
  7. Create an API key in this workspace and add it to Amp under Model Routing. You can also add a key for the whole Amp workspace under Workspace Model Routing.

Use credentials from this data retention workspace for Claude Fable 5 requests. Credentials from an Anthropic zero data retention workspace do not have access to Claude Fable 5. If your organization uses Workload Identity Federation instead of API keys, configure it for the same data retention workspace.