add black-box debug harness

internal/harness/scenarios/child_exit.json

@@ -0,0 +1,23 @@
+{
+  "name": "child_exit",
+  "trust": ["exit0"],
+  "presets": {
+    "processes": [
+      {
+        "name": "exit0",
+        "argv": ["sh", "-lc", "exit 0"]
+      }
+    ]
+  },
+  "steps": [
+    {
+      "type": "mcp_call",
+      "method": "spawn_process",
+      "params": { "kind": "command", "preset": "exit0" },
+      "save_as": "proc"
+    },
+    { "type": "wait_stable", "timeout_ms": 3000 },
+    { "type": "assert_mcp", "method": "list_processes", "path": "0.status", "equals": "exited" },
+    { "type": "assert_mcp", "method": "list_processes", "path": "0.exit_code", "equals": 0 }
+  ]
+}

internal/harness/scenarios/mcp_send_input.json

@@ -0,0 +1,30 @@
+{
+  "name": "mcp_send_input",
+  "steps": [
+    {
+      "type": "mcp_call",
+      "method": "spawn_process",
+      "params": {
+        "kind": "command",
+        "argv": ["sh", "-lc", "read line; echo got:$line; sleep 5"],
+        "name": "reader"
+      },
+      "save_as": "proc"
+    },
+    {
+      "type": "mcp_call",
+      "method": "send_input",
+      "params": {
+        "process_id": "{{proc.process_id}}",
+        "kind": "text",
+        "text": "hello",
+        "submit": true,
+        "wait_ms": 250,
+        "tail_mode": "grid"
+      },
+      "save_as": "input"
+    },
+    { "type": "assert_saved", "from": "input", "path": "tail.content", "contains": "got:hello" },
+    { "type": "wait_text", "contains": "got:hello", "timeout_ms": 5000 }
+  ]
+}

internal/harness/scenarios/spawn_process_via_palette.json

@@ -0,0 +1,26 @@
+{
+  "name": "spawn_process_via_palette",
+  "presets": {
+    "processes": [
+      {
+        "name": "ready",
+        "argv": ["ready-script"]
+      }
+    ]
+  },
+  "scripts": [
+    {
+      "name": "ready-script",
+      "body": "#!/bin/sh\necho READY\nsleep 5\n"
+    }
+  ],
+  "steps": [
+    { "type": "wait_stable", "timeout_ms": 3000 },
+    { "type": "send_chord", "chord": "ctrl-k" },
+    { "type": "send_text", "text": "ready" },
+    { "type": "send_chord", "chord": "enter" },
+    { "type": "wait_text", "contains": "READY", "timeout_ms": 5000 },
+    { "type": "assert_mcp", "method": "list_processes", "path": "0.name", "equals": "ready" },
+    { "type": "assert_mcp", "method": "list_processes", "path": "0.status", "equals": "running" }
+  ]
+}

internal/harness/scenarios/switch_via_palette.json

@@ -0,0 +1,34 @@
+{
+  "name": "switch_via_palette",
+  "scripts": [
+    {
+      "name": "named-loop",
+      "body": "#!/bin/sh\necho \"$1 READY\"\nsleep 5\n"
+    }
+  ],
+  "steps": [
+    {
+      "type": "mcp_call",
+      "method": "spawn_process",
+      "params": { "kind": "command", "argv": ["named-loop", "first"], "name": "first" },
+      "save_as": "first"
+    },
+    {
+      "type": "mcp_call",
+      "method": "spawn_process",
+      "params": { "kind": "command", "argv": ["named-loop", "second"], "name": "second" },
+      "save_as": "second"
+    },
+    { "type": "wait_text", "contains": "second READY", "timeout_ms": 5000 },
+    { "type": "send_chord", "chord": "ctrl-k" },
+    { "type": "send_text", "text": "Switch to first" },
+    { "type": "send_chord", "chord": "enter" },
+    { "type": "wait_text", "contains": "first READY", "timeout_ms": 5000 },
+    {
+      "type": "assert_mcp",
+      "method": "get_project_status",
+      "path": "processes.0.name",
+      "equals": "first"
+    }
+  ]
+}

internal/harness/scenarios/trust_required.json

@@ -0,0 +1,19 @@
+{
+  "name": "trust_required",
+  "presets": {
+    "processes": [
+      {
+        "name": "untrusted",
+        "argv": ["sh", "-lc", "echo should-not-run"]
+      }
+    ]
+  },
+  "steps": [
+    {
+      "type": "assert_mcp",
+      "method": "spawn_process",
+      "params": { "kind": "command", "preset": "untrusted" },
+      "error_kind": "needs_trust"
+    }
+  ]
+}