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Short definitions for the terms used across the docs.
  • Agent session — a persistent conversation with the agent, backed by an IPython kernel and a transcript on disk. See Sessions.
  • Daemon — the background agent process that CLI, TUI, and web attach to. See Daemon.
  • Subagent / RLM — a child agent spawned from an IPython cell via rlm(...). See Subagents (RLM).
  • Extension — an importable package that adds tools, slash commands, shortcuts, or UI. See Extensions.
  • Skill — an executable package (markdown or Python) that teaches the agent a workflow. Registers as an extension. See Skills.
  • Compaction — trimming context to fit the model window. See Sessions.
  • Refinement — updating supplemental harness state from a session trajectory. See Refinement.
  • Protocol / contract — chat-protocol.ts (stream events) and fleet-contract.ts (attachments, projects, OpenUI).
  • BEUI — the design token and component library under web/design.
  • IPython kernel provisioner — IpythonKernelProvisioner, provisioned lazily per session.
  • AgentSessionEvent — session-level events emitted by the runtime.
  • ChatStreamEvent — NDJSON event shape the web adapter emits to browsers.
  • AgentMessage — the message payload written to session transcripts.
  • AgentTool — the tool interface every built-in and extension tool implements.
Last modified on August 17, 2026