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mode, the wrap-up keeps the tools and runs no call, a withdrawn tool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>

tests/budget.test.ts

@@ -25,7 +25,7 @@ function app(limits: string, script: Parameters<typeof fakeProvider>[0], ask: ()
 
 const tools = (r: any) => (r.tools ?? []).map((t: any) => t.function.name)
 
-test("past the output budget the tools are withdrawn, the model is told, and it answers", async () => {
+test("past the output budget the model is told the tools are withdrawn, and it answers; the list stays the session's", async () => {
   const a = app("output_bytes: 1000", [
     { chunks: [toolCall(0, "r1", "read", '{"path":"big.txt"}')] },
     { chunks: [delta({ content: "It is a file of x." }, "stop")] },
@@ -34,7 +34,7 @@ test("past the output budget the tools are withdrawn, the model is told, and it
   a.bus.on((e: Event) => e.type === "notice" && notices.push(e.message))
   expect(await a.engine.prompt("what is in big.txt?")).toBe("budget")
   expect(tools(fake!.requests[0])).toContain("read")
-  expect(tools(fake!.requests[1])).toEqual([])
+  expect(tools(fake!.requests[1])).toEqual(tools(fake!.requests[0]))
   expect(JSON.stringify(fake!.requests[1].messages.at(-1))).toContain("The tool output budget for this prompt has been reached")
   expect(notices.join("\n")).toContain("with too much tool output to read")
 })
@@ -44,8 +44,8 @@ test("the token budget counts what the model wrote this prompt", async () => {
     { chunks: [toolCall(0, "r1", "read", '{"path":"big.txt"}'), usage(10, 80)] },
     { chunks: [delta({ content: "done" }, "stop")] },
   ])
-  await a.engine.prompt("go")
-  expect(tools(fake!.requests[1])).toEqual([])
+  expect(await a.engine.prompt("go")).toBe("budget")
+  expect(JSON.stringify(fake!.requests[1].messages.at(-1))).toContain("The output budget for this prompt has been reached")
 })
 
 test("time spent waiting for an approval is not spent from the wall-clock budget", async () => {