Migrate to the single agent plane

This migration removes public wrappers that owned overlapping loop, chat, and editor-completion behavior. Migrate each call to the capability that owns its lifecycle.

Replace AgentLoopOptions

Rename the annotation to AgentSpec. The fields remain flat, so existing values need no reshaping.

import { AgentSpec, agent_options } from "std/agent/options"

const spec: AgentSpec = agent_options({
  provider: "openai",
  model: "gpt-5-mini",
  loop_until_done: true,
})

Use the component records when a function accepts only part of the contract: AgentModelSpec, AgentExecutionSpec, AgentCapabilitySpec, AgentLifecycleSpec, AgentContextSpec, and AgentObservabilitySpec.

Replace agent_turn

Call agent_loop and set completion policy explicitly. Use done_judge when a judge must approve completion.

const result = agent_loop(harness, task, system, agent_options({
  provider: "openai",
  model: "gpt-5-mini",
  loop_until_done: true,
  done_judge: true,
}))

Read judge decisions from judge_decision session events. The removed wrapper's separate iterations and judge_decisions result summaries are not part of AgentResult.

Replace agent_llm_turn

Use harness.llm.call(prompt, system?, options?). One request belongs to HarnessLlm; adding an agent-named wrapper does not make it an agent loop.

Replace agent_chat_loop

Keep input handling, slash commands, and presentation in the host. Invoke agent_loop once per prompt turn. Pass history when the host owns conversation storage, or reuse a session_id when the Harn session owns it.

const result = agent_loop(harness, message, system, agent_options({
  session_id: conversation_id,
  history: stored_messages,
  tools: tools,
}))

Use typed HITL or agent_await_resumption for suspension. Do not recreate the removed wait_for_user convention as a terminal string.

Move editor completions to the host

std/agent/completions is removed. Editors own cursor state, suggestion UI, acceptance decisions, and product telemetry. Call harness.llm.completion for one completion request and store host-specific envelopes in the product layer.

Update result handling

Annotate loop results with AgentResult from std/agent/contracts. Branch on result.terminal.kind; retain stop_reason only for diagnostics.

agent_loop no longer returns an untyped nullable dictionary. Remove defensive optional access on the result itself (result?.status becomes result.status); keep optional access only for fields whose declared type is optional.

If a reader imports AgentResult from std/agent/artifacts, rename that annotation to AgentResultArtifact. The artifact type remains compatible with persisted v1/v2 files; AgentResult now names only the live loop contract from std/agent/contracts.

import { AgentResult } from "std/agent/contracts"

const result: AgentResult = agent_loop(harness, task, system, spec)
if result.terminal.kind == "natural" {
  return result.visible_text
}
throw "agent stopped: " + result.terminal.kind + ": " + result.terminal.reason