Harness spec 1.1.0: one plan, prototypes and the library shared; the CLI implements it

The spec: plan_write and plan_update (new, shared, offered in every mode) and
plan_submit (now shared) keep one structured plan — findings, objectives,
phases of tasks — in place of the todo list, which lives on as a former name
of plan_write. The shared system text is one text for both projects, with
variables for what differs; the mode texts, a prototypes block and a library
block are shared. acp.md: the client hands the device what only it knows
(context, library, prototypes), the plan travels as a structure (plan_state),
library calls carry the chat's scope, and a client may rewind a session.
loop.json says its numbers as numbers. Four conformance areas: plan,
prototype, library_scope, toolcall_index.

The CLI: the plan is kept per session in the store and drawn above the prompt
and on the approval card; the prompt is assembled from the spec's texts with
their variables filled; the link reads the instance's instructions,
personalization, knowledge scope and prototype offer, sends the plan as a
structure and answers rewind; library calls to the instance carry the session
as scope; a prototype written in the terminal is saved as a file and named in
the transcript; a tool-call fragment without an index continues the last call;
the default theme is Moria; dead exports and Hermes leftovers removed.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/tool/plan_update.ts

@@ -0,0 +1,34 @@
+// plan_update: the plan changed as the work goes — a task marked doing or done, one dropped with
+// why, work added, a finding recorded. Several changes in one call; an unknown id is an error
+// naming the known ones, and then nothing changes (src/plan/plan.ts apply).
+import { z } from "zod"
+import { described } from "../harness.ts"
+import { apply, OBJECTIVE_STATUSES, PHASE_STATUSES, render, TASK_STATUSES } from "../plan/plan.ts"
+import { planTitle } from "./plan_write.ts"
+import { defineTool } from "./tool.ts"
+
+const asList = (v: unknown) => (v === undefined || v === null || Array.isArray(v) ? v : [v])
+
+export const planUpdateSchema = z.object({
+  tasks: z.preprocess(asList, z.array(z.object({ id: z.string().min(1), status: z.enum(TASK_STATUSES).optional(), note: z.string().max(300).optional() }))).optional(),
+  objectives: z.preprocess(asList, z.array(z.object({ id: z.string().min(1), status: z.enum(OBJECTIVE_STATUSES) }))).optional(),
+  phases: z.preprocess(asList, z.array(z.object({ id: z.string().min(1), status: z.enum(PHASE_STATUSES) }))).optional(),
+  add_tasks: z.preprocess(asList, z.array(z.object({ phase: z.string().min(1), text: z.string().min(1).max(300), after: z.string().optional() }))).optional(),
+  add_findings: z.preprocess(asList, z.array(z.string().min(1).max(300))).optional(),
+})
+
+export const planUpdateTool = defineTool({
+  ...described("plan_update"),
+  purpose: false,
+  access: "plan",
+  schema: planUpdateSchema,
+  permission: () => ({ permission: "plan", class: "interact", patterns: ["*"] }),
+  async run(a, ctx) {
+    const current = ctx.plan?.get()
+    if (!current) return { output: "There is no plan to update. Write one with plan_write first.", isError: true }
+    const r = apply(current, a)
+    if ("error" in r) return { output: r.error, isError: true }
+    ctx.plan?.set(r.plan)
+    return { output: render(r.plan), title: planTitle(r.plan) }
+  },
+})