fix: structure cold-start branch boundary

scripts/cold-start-contract.mjs

@@ -23,7 +23,7 @@ export const coldStartResponseSchema = {
     "promotion_status",
     "next_task",
     "proof_commands",
-    "branch_boundary",
+    "main_edits_allowed",
     "evidence_files"
   ],
   properties: {
@@ -36,7 +36,7 @@ export const coldStartResponseSchema = {
       items: { type: "string" },
       minItems: REQUIRED_PROOF_COMMANDS.length
     },
-    branch_boundary: { type: "string" },
+    main_edits_allowed: { type: "boolean" },
     evidence_files: {
       type: "array",
       items: { type: "string" },
@@ -90,8 +90,7 @@ export function verifyColdStartResponse(
     throw new Error("cold-start response reported the wrong next task");
   }
   requireExactArrayValues(response.proof_commands, REQUIRED_PROOF_COMMANDS, "proof commands");
-  const boundary = String(response.branch_boundary || "").toLowerCase();
-  if (!/(branch|worktree)/.test(boundary) || !boundary.includes("main") || !/(do not|don't|avoid|not edit|prohibit)/.test(boundary)) {
+  if (response.main_edits_allowed !== false) {
     throw new Error("cold-start response did not preserve the protected branch boundary");
   }
   requireEvidenceFiles(response.evidence_files);

scripts/run-cold-start-smoke.mjs

@@ -64,7 +64,7 @@ const prompt = [
   "This is a cold-start readback: use only current Git state and files inside this repository.",
   "Do not rely on prior sessions, chat history, saved checkpoints, or external memory.",
   "Begin by reading AGENTS.md, then follow its restart instructions.",
-  "Identify the exact current HEAD commit, frozen comparison baseline, promotion decision, first unfinished task, complete candidate proof commands, protected-branch boundary, and repository files that prove the answer.",
+  "Identify the exact current HEAD commit, frozen comparison baseline, promotion decision, first unfinished task, complete candidate proof commands, whether meaningful edits on main are allowed, and repository files that prove the answer.",
   "Do not edit files. Return only the structured response requested by the output schema."
 ].join(" ");
 

scripts/test-cold-start-contract.mjs

@@ -36,7 +36,7 @@ const valid = {
     "npm run benchmark:sealed",
     "npm run benchmark:trajectories"
   ],
-  branch_boundary: "Create a branch or worktree; do not edit main.",
+  main_edits_allowed: false,
   evidence_files: [
     "AGENTS.md",
     "docs/plans/adaptive-harness-candidate.md",
@@ -76,14 +76,6 @@ assert.equal(
   }).source_evidence_complete,
   true
 );
-assert.equal(
-  verifyColdStartResponse({
-    ...valid,
-    branch_boundary: "Meaningful edits remain prohibited on main; use this worktree."
-  }).protected_branch_boundary,
-  true
-);
-
 assert.throws(
   () => verifyColdStartResponse({ ...valid, source_commit: FROZEN_BASELINE_COMMIT }),
   /source commit/
@@ -105,7 +97,7 @@ assert.throws(
   /proof commands/
 );
 assert.throws(
-  () => verifyColdStartResponse({ ...valid, branch_boundary: "Edit main directly." }),
+  () => verifyColdStartResponse({ ...valid, main_edits_allowed: true }),
   /branch boundary/
 );