diff --git a/REPORT-T1.md b/REPORT-T1.md
new file mode 100644
index 00000000..5ef8a7c2
--- /dev/null
+++ b/REPORT-T1.md
@@ -0,0 +1,94 @@
+# T1 report: canonical ungated Claude base and lease overlay
+
+## Changed
+
+- Replaced `packages/mosaic/framework/runtime/claude/settings.json` with the canonical ungated base. It retains the model, QA hooks, plugins, command allowlist, permissions, and `mcpServers.sequential-thinking`.
+- Added `packages/mosaic/framework/runtime/claude/lease-overlay.json`. It contains only `hooks` and the six removed lease hook entries.
+- Added the byte-identical pre-split source fixture at `packages/mosaic/src/runtime/fixtures/claude-settings.gated.pre-split.json`.
+- Added `packages/mosaic/src/runtime/claude-settings-base.spec.ts`.
+
+`framework-manifest.txt` already declares `runtime/**`, so the new overlay is framework-owned and shipped without a manifest change.
+
+## Lease-hook enumeration
+
+The actual template has six lease hook entries, matching fred's refined boundary:
+
+1. `PreToolUse` matcher `.*`: `mutator-gate.py`
+2. `Stop`: one combined command containing `receipt-observer-client.py` then `promote-complete.py`
+3. `UserPromptSubmit` matcher `^/mosaic-promote$`: `promote-begin.py`
+4. `PreCompact`: `revoke-lease.py --reason pre-compact`
+5. `SessionStart` matcher `compact`: `revoke-lease.py --reason session-start-compact`
+6. `SessionStart` matcher `resume|clear`: `revoke-lease.py --reason session-start-rollover --bump-generation`
+
+There is no delta from the refined six-entry enumeration. The Stop entry contains the receipt-observer and promote-complete commands together, rather than as two separate hook objects.
+
+## Tests and checks
+
+`pnpm install --frozen-lockfile` was run first because `node_modules` was absent. It completed successfully.
+
+Red-first run before artifacts existed:
+
+```text
+RUN  v2.1.9 .../packages/mosaic
+❯ src/runtime/claude-settings-base.spec.ts (4 tests | 4 failed)
+× keeps every lease command out of the ungated base
+  → mutator-gate: expected true to be false
+× reconstructs the pre-split gated hooks while retaining the canonical MCP correction
+  → ENOENT: .../lease-overlay.json
+× ships sequential-thinking in the base
+  → expected undefined to deeply equal { 'sequential-thinking': ... }
+× limits the overlay to lease hook entries
+  → ENOENT: .../lease-overlay.json
+```
+
+Final focused acceptance run:
+
+```text
+RUN  v2.1.9 .../packages/mosaic
+✓ src/runtime/claude-settings-base.spec.ts (4 tests) 19ms
+Test Files  1 passed (1)
+Tests  4 passed (4)
+```
+
+`pnpm --filter @mosaicstack/mosaic lint` passed:
+
+```text
+> @mosaicstack/mosaic@0.0.49 lint
+> eslint src
+```
+
+`pnpm --filter @mosaicstack/mosaic typecheck` failed on pre-existing workspace resolution and unrelated package errors. The new spec no longer appears in the error list. Initial failures include missing `@mosaicstack/{brain,forge,log,macp,memory,queue,storage,quality-rails,db,config,prdy,types}` declarations, followed by existing `fleet-backlog.ts`, `gateway-doctor.ts`, and TUI implicit-`any` errors. Exit status: 2.
+
+A focused legacy consumer run confirms an existing assumption that `settings.json` itself is gated:
+
+```text
+pnpm --filter @mosaicstack/mosaic exec vitest run src/mutator-gate/mutator-gate.acceptance.spec.ts
+❯ src/mutator-gate/mutator-gate.acceptance.spec.ts (20 tests | 6 failed)
+× non-dangerous parser residual is denied by the global all-tools hook without a lease
+  → expected all-tools mutator-gate command in settings.json
+× Claude and Pi compaction observer wiring is complete and fail-closed
+  → expected PreCompact/SessionStart revoke-lease hooks in settings.json
+```
+
+The other four failures in that focused run reported `STALE_GENERATION` where the test expected `MUTATOR_UNVERIFIED`, plus one successful-gate assertion. I did not redesign this legacy suite because the task explicitly says to report consumers that assume the base is gated.
+
+## Consumers found
+
+Direct `runtime/claude/settings.json` path consumers found by the required repository grep:
+
+- `packages/mosaic/framework/tools/_scripts/mosaic-link-runtime-assets`: copies the base to `~/.claude/settings.json`.
+- `packages/mosaic/src/commands/install-ordering-guard.ts` and `.spec.ts`: documentation and behavior assume the source embeds enforcement hooks.
+- `packages/mosaic/framework/tools/_scripts/test-install-ordering-guard.sh`: comments and assertions expect `mutator-gate.py` and `receipt-observer-client.py` in the base.
+- `packages/mosaic/src/mutator-gate/mutator-gate.acceptance.spec.ts`: reads the base and asserts mutator, promotion, and compaction lease wiring.
+- `packages/mosaic/src/lease-broker/promotion_trigger_unittest.py`: reads the base and asserts promotion wiring.
+- `packages/mosaic/src/lease-broker/recovery_runtime_unittest.py`: reads the base.
+- `packages/mosaic/src/runtime/update-checker.ts` and `.spec.ts`: references the path in settings wiring/update checks.
+- Documentation-only references: `docs/compaction-refresh/probes/p6_constrained_recovery.py`, `docs/plans/agent-reflection-loop-PRD.md`, `docs/tasks/544-agent-reflection-loop.md`, and the framework QA documentation/scripts found by grep.
+
+I did not change these consumers. The install/link and lease acceptance consumers must be taught to select and compose `lease-overlay.json` when a gated promotion seat is requested. That composition behavior is outside T1.
+
+## Ambiguity handled
+
+The exact pre-split template fixture has no `mcpServers` key (SHA-256 `44e74ea1e9d424fffa020ee666402662ac856b88bf6ae7f3b8931eed29dc75a4`). The task simultaneously requires a byte-for-byte pre-split fixture, `mcpServers.sequential-thinking` in the base, and `deep-merge(base, overlay) == original`. Those three conditions cannot all hold because a merge cannot remove the required MCP key.
+
+The acceptance test preserves the exact fixture and asserts that the normalized merge equals the pre-split template plus the required canonical `mcpServers.sequential-thinking` correction. It verifies all original hook content is reconstructed and the base carries the required MCP. Production three-layer merge semantics remain W-F1 work.
diff --git a/packages/mosaic/framework/runtime/claude/lease-overlay.json b/packages/mosaic/framework/runtime/claude/lease-overlay.json
new file mode 100644
index 00000000..c2deaa11
--- /dev/null
+++ b/packages/mosaic/framework/runtime/claude/lease-overlay.json
@@ -0,0 +1,70 @@
+{
+  "hooks": {
+    "PreCompact": [
+      {
+        "matcher": ".*",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 \"$HOME/.config/mosaic/tools/lease-broker/revoke-lease.py\" --runtime claude --reason pre-compact"
+          }
+        ]
+      }
+    ],
+    "SessionStart": [
+      {
+        "matcher": "compact",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 \"$HOME/.config/mosaic/tools/lease-broker/revoke-lease.py\" --runtime claude --reason session-start-compact"
+          }
+        ]
+      },
+      {
+        "matcher": "resume|clear",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 \"$HOME/.config/mosaic/tools/lease-broker/revoke-lease.py\" --runtime claude --reason session-start-rollover --bump-generation"
+          }
+        ]
+      }
+    ],
+    "UserPromptSubmit": [
+      {
+        "matcher": "^/mosaic-promote$",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 ~/.config/mosaic/tools/lease-broker/promote-begin.py",
+            "timeout": 15
+          }
+        ]
+      }
+    ],
+    "PreToolUse": [
+      {
+        "matcher": ".*",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 ~/.config/mosaic/tools/lease-broker/mutator-gate.py --runtime claude --recovery-command ~/.config/mosaic/tools/lease-broker/recover-context.py",
+            "timeout": 3
+          }
+        ]
+      }
+    ],
+    "Stop": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 ~/.config/mosaic/tools/lease-broker/receipt-observer-client.py --runtime claude --latest-entry; observer_status=$?; python3 ~/.config/mosaic/tools/lease-broker/promote-complete.py; exit $observer_status",
+            "timeout": 15
+          }
+        ]
+      }
+    ]
+  }
+}
diff --git a/packages/mosaic/framework/runtime/claude/settings.json b/packages/mosaic/framework/runtime/claude/settings.json
index 0e6dcec1..bf79b5ba 100644
--- a/packages/mosaic/framework/runtime/claude/settings.json
+++ b/packages/mosaic/framework/runtime/claude/settings.json
@@ -1,60 +1,7 @@
 {
   "model": "opus",
   "hooks": {
-    "PreCompact": [
-      {
-        "matcher": ".*",
-        "hooks": [
-          {
-            "type": "command",
-            "command": "python3 \"$HOME/.config/mosaic/tools/lease-broker/revoke-lease.py\" --runtime claude --reason pre-compact"
-          }
-        ]
-      }
-    ],
-    "SessionStart": [
-      {
-        "matcher": "compact",
-        "hooks": [
-          {
-            "type": "command",
-            "command": "python3 \"$HOME/.config/mosaic/tools/lease-broker/revoke-lease.py\" --runtime claude --reason session-start-compact"
-          }
-        ]
-      },
-      {
-        "matcher": "resume|clear",
-        "hooks": [
-          {
-            "type": "command",
-            "command": "python3 \"$HOME/.config/mosaic/tools/lease-broker/revoke-lease.py\" --runtime claude --reason session-start-rollover --bump-generation"
-          }
-        ]
-      }
-    ],
-    "UserPromptSubmit": [
-      {
-        "matcher": "^/mosaic-promote$",
-        "hooks": [
-          {
-            "type": "command",
-            "command": "python3 ~/.config/mosaic/tools/lease-broker/promote-begin.py",
-            "timeout": 15
-          }
-        ]
-      }
-    ],
     "PreToolUse": [
-      {
-        "matcher": ".*",
-        "hooks": [
-          {
-            "type": "command",
-            "command": "python3 ~/.config/mosaic/tools/lease-broker/mutator-gate.py --runtime claude --recovery-command ~/.config/mosaic/tools/lease-broker/recover-context.py",
-            "timeout": 3
-          }
-        ]
-      },
       {
         "matcher": "Write|Edit|MultiEdit",
         "hooks": [
@@ -91,11 +38,6 @@
     "Stop": [
       {
         "hooks": [
-          {
-            "type": "command",
-            "command": "python3 ~/.config/mosaic/tools/lease-broker/receipt-observer-client.py --runtime claude --latest-entry; observer_status=$?; python3 ~/.config/mosaic/tools/lease-broker/promote-complete.py; exit $observer_status",
-            "timeout": 15
-          },
           {
             "type": "command",
             "command": "~/.config/mosaic/tools/qa/reflect-stop-hook.sh",
@@ -315,5 +257,11 @@
     "cpan",
     "nohup"
   ],
-  "enableAllMcpTools": true
+  "enableAllMcpTools": true,
+  "mcpServers": {
+    "sequential-thinking": {
+      "command": "npx",
+      "args": ["-y", "@modelcontextprotocol/server-sequential-thinking"]
+    }
+  }
 }
diff --git a/packages/mosaic/src/runtime/claude-settings-base.spec.ts b/packages/mosaic/src/runtime/claude-settings-base.spec.ts
new file mode 100644
index 00000000..71cf7c95
--- /dev/null
+++ b/packages/mosaic/src/runtime/claude-settings-base.spec.ts
@@ -0,0 +1,131 @@
+import { readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import { describe, expect, it } from 'vitest';
+
+type Json = null | boolean | number | string | Json[] | { [key: string]: Json };
+type JsonObject = { [key: string]: Json };
+
+const frameworkRoot = fileURLToPath(new URL('../../framework/', import.meta.url));
+const basePath = `${frameworkRoot}runtime/claude/settings.json`;
+const overlayPath = `${frameworkRoot}runtime/claude/lease-overlay.json`;
+const gatedFixturePath = fileURLToPath(
+  new URL('./fixtures/claude-settings.gated.pre-split.json', import.meta.url),
+);
+
+function readJson(path: string): JsonObject {
+  return JSON.parse(readFileSync(path, 'utf8')) as JsonObject;
+}
+
+function isObject(value: unknown): value is JsonObject {
+  return typeof value === 'object' && value !== null && !Array.isArray(value);
+}
+
+// This fixture contract composes hook event arrays additively. It is deliberately
+// limited to verifying that the split is lossless; production launch merge
+// semantics remain owned by W-F1.
+function deepMerge(base: Json, overlay: Json): Json {
+  if (Array.isArray(base) && Array.isArray(overlay)) {
+    const merged = [...base];
+    for (const entry of overlay) {
+      if (!isObject(entry) || !Array.isArray(entry['hooks'])) {
+        merged.push(entry);
+        continue;
+      }
+      const matchingIndex = merged.findIndex(
+        (candidate) =>
+          isObject(candidate) &&
+          Array.isArray(candidate['hooks']) &&
+          candidate['matcher'] === entry['matcher'],
+      );
+      if (matchingIndex === -1) merged.push(entry);
+      else merged[matchingIndex] = deepMerge(merged[matchingIndex]!, entry);
+    }
+    return merged;
+  }
+  if (isObject(base) && isObject(overlay)) {
+    const merged: JsonObject = { ...base };
+    for (const [key, value] of Object.entries(overlay)) {
+      merged[key] = key in merged ? deepMerge(merged[key]!, value) : value;
+    }
+    return merged;
+  }
+  return overlay;
+}
+
+function normalize(value: Json): Json {
+  if (Array.isArray(value)) {
+    return value
+      .map(normalize)
+      .sort((left, right) => JSON.stringify(left).localeCompare(JSON.stringify(right)));
+  }
+  if (isObject(value)) {
+    return Object.fromEntries(
+      Object.entries(value)
+        .sort(([left], [right]) => left.localeCompare(right))
+        .map(([key, nested]) => [key, normalize(nested)]),
+    );
+  }
+  return value;
+}
+
+function hookCommands(settings: JsonObject): string[] {
+  const hooks = settings['hooks'];
+  if (!isObject(hooks)) return [];
+
+  return Object.values(hooks).flatMap((event) => {
+    if (!Array.isArray(event)) return [];
+    return event.flatMap((entry) => {
+      if (!isObject(entry) || !Array.isArray(entry['hooks'])) return [];
+      return entry['hooks'].flatMap((hook) =>
+        isObject(hook) && typeof hook['command'] === 'string' ? [hook['command']] : [],
+      );
+    });
+  });
+}
+
+const sequentialThinking: JsonObject = {
+  command: 'npx',
+  args: ['-y', '@modelcontextprotocol/server-sequential-thinking'],
+};
+
+describe('canonical Claude base and lease-promotion overlay', () => {
+  it('keeps every lease command out of the ungated base', () => {
+    const base = readJson(basePath);
+    const commands = hookCommands(base);
+
+    for (const marker of ['mutator-gate', 'receipt-observer', 'promote-', 'revoke-lease']) {
+      expect(
+        commands.some((command) => command.includes(marker)),
+        marker,
+      ).toBe(false);
+    }
+  });
+
+  it('reconstructs the pre-split gated hooks while retaining the canonical MCP correction', () => {
+    const base = readJson(basePath);
+    const overlay = readJson(overlayPath);
+    const preSplit = readJson(gatedFixturePath);
+    const expected: JsonObject = {
+      ...preSplit,
+      mcpServers: { 'sequential-thinking': sequentialThinking },
+    };
+
+    expect(normalize(deepMerge(base, overlay))).toEqual(normalize(expected));
+  });
+
+  it('ships sequential-thinking in the base', () => {
+    const base = readJson(basePath);
+    expect(base['mcpServers']).toEqual({ 'sequential-thinking': sequentialThinking });
+  });
+
+  it('limits the overlay to lease hook entries', () => {
+    const overlay = readJson(overlayPath);
+    expect(Object.keys(overlay)).toEqual(['hooks']);
+
+    const commands = hookCommands(overlay);
+    expect(commands).toHaveLength(6);
+    for (const command of commands) {
+      expect(command).toMatch(/mutator-gate|receipt-observer|promote-|revoke-lease/);
+    }
+  });
+});
diff --git a/packages/mosaic/src/runtime/fixtures/claude-settings.gated.pre-split.json b/packages/mosaic/src/runtime/fixtures/claude-settings.gated.pre-split.json
new file mode 100644
index 00000000..0e6dcec1
--- /dev/null
+++ b/packages/mosaic/src/runtime/fixtures/claude-settings.gated.pre-split.json
@@ -0,0 +1,319 @@
+{
+  "model": "opus",
+  "hooks": {
+    "PreCompact": [
+      {
+        "matcher": ".*",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 \"$HOME/.config/mosaic/tools/lease-broker/revoke-lease.py\" --runtime claude --reason pre-compact"
+          }
+        ]
+      }
+    ],
+    "SessionStart": [
+      {
+        "matcher": "compact",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 \"$HOME/.config/mosaic/tools/lease-broker/revoke-lease.py\" --runtime claude --reason session-start-compact"
+          }
+        ]
+      },
+      {
+        "matcher": "resume|clear",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 \"$HOME/.config/mosaic/tools/lease-broker/revoke-lease.py\" --runtime claude --reason session-start-rollover --bump-generation"
+          }
+        ]
+      }
+    ],
+    "UserPromptSubmit": [
+      {
+        "matcher": "^/mosaic-promote$",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 ~/.config/mosaic/tools/lease-broker/promote-begin.py",
+            "timeout": 15
+          }
+        ]
+      }
+    ],
+    "PreToolUse": [
+      {
+        "matcher": ".*",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 ~/.config/mosaic/tools/lease-broker/mutator-gate.py --runtime claude --recovery-command ~/.config/mosaic/tools/lease-broker/recover-context.py",
+            "timeout": 3
+          }
+        ]
+      },
+      {
+        "matcher": "Write|Edit|MultiEdit",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "~/.config/mosaic/tools/qa/prevent-memory-write.sh",
+            "timeout": 10
+          }
+        ]
+      }
+    ],
+    "PostToolUse": [
+      {
+        "matcher": "Edit|MultiEdit|Write",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "~/.config/mosaic/tools/qa/qa-hook-stdin.sh",
+            "timeout": 60
+          }
+        ]
+      },
+      {
+        "matcher": "Edit|MultiEdit|Write",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "~/.config/mosaic/tools/qa/typecheck-hook.sh",
+            "timeout": 30
+          }
+        ]
+      }
+    ],
+    "Stop": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "python3 ~/.config/mosaic/tools/lease-broker/receipt-observer-client.py --runtime claude --latest-entry; observer_status=$?; python3 ~/.config/mosaic/tools/lease-broker/promote-complete.py; exit $observer_status",
+            "timeout": 15
+          },
+          {
+            "type": "command",
+            "command": "~/.config/mosaic/tools/qa/reflect-stop-hook.sh",
+            "timeout": 15
+          }
+        ]
+      }
+    ]
+  },
+  "enabledPlugins": {
+    "frontend-design@claude-plugins-official": true,
+    "feature-dev@claude-plugins-official": true,
+    "code-review@claude-plugins-official": true,
+    "pr-review-toolkit@claude-plugins-official": true
+  },
+  "skipDangerousModePermissionPrompt": true,
+  "allowedCommands": [
+    "npm",
+    "npm install",
+    "npm run",
+    "npm test",
+    "npm build",
+    "npm start",
+    "npm run dev",
+    "npm run build",
+    "npm run lint",
+    "npm run typecheck",
+    "npm run test:ci",
+    "npm run test:e2e",
+    "npm run test:unit",
+    "npm run test:integration",
+    "npm run test:cov",
+    "npm run test:security",
+    "npm run security:scan",
+    "npm run security:audit",
+    "npm run performance:benchmark",
+    "npm run build:dev",
+    "npm run build:prod",
+    "npm run test",
+    "npm run test:watch",
+    "npm run migrate",
+    "npm run migrate:rollback",
+    "npm run db:seed",
+    "npm run db:reset",
+    "node",
+    "yarn",
+    "pnpm",
+    "npx",
+    "npx tsc",
+    "npx eslint",
+    "npx prettier",
+    "npx jest",
+    "npx vitest",
+    "git",
+    "git add",
+    "git commit",
+    "git push",
+    "git pull",
+    "git status",
+    "git diff",
+    "git log",
+    "git branch",
+    "git checkout",
+    "git merge",
+    "git init",
+    "git remote",
+    "git fetch",
+    "git reset",
+    "git rebase",
+    "git stash",
+    "git tag",
+    "git show",
+    "git config",
+    "gh",
+    "gh issue",
+    "gh pr",
+    "gh repo",
+    "gh api",
+    "docker",
+    "docker build",
+    "docker run",
+    "docker ps",
+    "docker logs",
+    "docker exec",
+    "docker stop",
+    "docker start",
+    "docker pull",
+    "docker push",
+    "docker-compose",
+    "docker-compose up",
+    "docker-compose down",
+    "docker-compose build",
+    "docker-compose logs",
+    "docker-compose ps",
+    "docker-compose exec",
+    "kubectl",
+    "kubectl get",
+    "kubectl describe",
+    "kubectl logs",
+    "kubectl apply",
+    "kubectl delete",
+    "kubectl port-forward",
+    "mkdir",
+    "touch",
+    "chmod",
+    "chown",
+    "ls",
+    "cd",
+    "pwd",
+    "cp",
+    "mv",
+    "rm",
+    "cat",
+    "echo",
+    "head",
+    "tail",
+    "grep",
+    "grep -E",
+    "grep -r",
+    "find",
+    "find -name",
+    "find -type",
+    "find -path",
+    "find -exec",
+    "find . -type f",
+    "find . -type d",
+    "wc",
+    "sort",
+    "uniq",
+    "curl",
+    "wget",
+    "ping",
+    "netstat",
+    "ss",
+    "lsof",
+    "psql",
+    "pg_dump",
+    "pg_restore",
+    "sqlite3",
+    "jest",
+    "vitest",
+    "playwright",
+    "cypress",
+    "artillery",
+    "lighthouse",
+    "tsc",
+    "eslint",
+    "prettier",
+    "snyk",
+    "semgrep",
+    "tar",
+    "gzip",
+    "unzip",
+    "zip",
+    "which",
+    "whoami",
+    "id",
+    "env",
+    "export",
+    "source",
+    "sleep",
+    "date",
+    "uptime",
+    "df",
+    "du",
+    "free",
+    "top",
+    "htop",
+    "ps",
+    "tree",
+    "jq",
+    "sed",
+    "awk",
+    "xargs",
+    "tee",
+    "test",
+    "true",
+    "false",
+    "basename",
+    "dirname",
+    "realpath",
+    "readlink",
+    "stat",
+    "file",
+    "make",
+    "cmake",
+    "gcc",
+    "g++",
+    "clang",
+    "python",
+    "python3",
+    "pip",
+    "pip3",
+    "pip install",
+    "poetry",
+    "pipenv",
+    "go",
+    "go build",
+    "go test",
+    "go run",
+    "go mod",
+    "cargo",
+    "rustc",
+    "ruby",
+    "gem",
+    "bundle",
+    "rake",
+    "java",
+    "javac",
+    "mvn",
+    "gradle",
+    "dotnet",
+    "msbuild",
+    "php",
+    "composer",
+    "perl",
+    "cpan",
+    "nohup"
+  ],
+  "enableAllMcpTools": true
+}