Harness spec 3.1.0: the prefix stays still, in the CLI

The system prompt is made once per session (start, compaction, model
switch), kept in session_meta and resent byte for byte; it holds no
date. What changes mid-session -- the date, a mode the person chose, a
plan or memory or instruction file they edited, a personality, MCP
instructions that arrived later -- is a <session-note> on the next user
message, stored with it. The tool list is fixed for the session:
plan_submit is always offered and answers unavailable outside plan
mode, the wrap-up keeps the tools and runs no call, a withdrawn tool
stays listed and answers its refusal; the first request waits up to
mcp_wait_ms for MCP servers. Compaction asks for its summary as the
next turn of the same conversation. Cached input tokens are parsed
(incl. llama.cpp timings), stored per request and shown in /context.

Spec: context.md §7/§10, loop.json context.note (+ plan_ended,
plan_own, personal, empty, mcp_wait_ms), modes.json plan.refused,
compact.md without the transcript heading. Conformance area prefix.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/harness.ts

@@ -76,8 +76,10 @@ export interface ToolSpecDef {
   offered?: "subagent"
   argument_aliases?: Record<string, string>
   /** Spec 3.0.0: what must hold for it to be offered — `display` (the session is shown where a file
-   *  can be opened: over the link, to a client that offers `show`), `page`, `forge` (the chat's). */
-  requires?: ("display" | "page" | "forge")[]
+   *  can be opened: over the link, to a client that offers `show`), `page`, `forge` (the chat's);
+   *  `plan` (3.1.0): plan mode. From 3.1.0 one that can come and go during a session does not
+   *  leave the tool out: it is offered and answers `unavailable` while unmet (context.md §10). */
+  requires?: ("display" | "page" | "forge" | "plan")[]
   /** What a call answers, word for word, when a requirement went away after the offer. */
   unavailable?: string
   /** `always`: put to the person in every mode, auto included; never remembered. */
@@ -131,6 +133,18 @@ export const LOOP: {
     dedupe: { by_hash: string[]; by_result: string[] }
     compaction: { heading: string; line: string; rows: number }
     reasoning: string
+    /** A note on the next user message (spec 3.1.0, context.md §10): its tags and its lines, in
+     *  the order they are said. */
+    note: { open: string; close: string; date: string; mode: string; plan: string; memory: string; instructions: string; personality: string; mcp: string; empty: string
+      /** What a note names the person's own instructions by (the instructions block's `{{path}}`). */
+      personal: string
+      /** For a chat, whose modes have no text of their own; the CLI says modes/<mode>.md. */
+      plan_ended: string
+      /** For a chat, which does not resend earlier tool results; the CLI's model has them. */
+      plan_own: string
+    }
+    /** How long a session waits for its configured MCP servers before its first request. */
+    mcp_wait_ms: number
   }
 } = LOOP_JSON