diff --git a/pi_wake_agent.skill.json b/pi_wake_agent.skill.json
new file mode 100644
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+++ b/pi_wake_agent.skill.json
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+{
+  "name": "pi_wake_agent",
+  "description": "Multi-agent wake-up timer with self-cron/daemon/succession modes. Sends doorbell injections via zellij and durable messages via h5i bus.",
+  "parameters": {
+    "type": "object",
+    "properties": {
+      "mode": {
+        "type": "string",
+        "enum": ["install", "once", "daemon", "succession", "run", "remove", "list", "status", "validate"],
+        "description": "Operation mode"
+      },
+      "interval": {
+        "type": "string",
+        "pattern": "^\\d+[hms]$",
+        "default": "1h",
+        "description": "Interval duration. Formats: 30m, 1h, 90m, 2h, 10s"
+      },
+      "session": {
+        "type": "array",
+        "items": { "type": "string" },
+        "description": "Zellij session name(s). Repeatable."
+      },
+      "sessions": {
+        "type": "string",
+        "description": "Comma-separated list of sessions"
+      },
+      "message": {
+        "type": "string",
+        "default": "Operator says CONTINUE. pi_nvnemo here, saying hi!",
+        "description": "Wake message sent to agent(s)"
+      },
+      "count": {
+        "type": "integer",
+        "minimum": 1,
+        "default": 1,
+        "description": "Number of runs for succession mode"
+      },
+      "dry_run": {
+        "type": "boolean",
+        "default": false,
+        "description": "Show what would be done without executing"
+      },
+      "debug": {
+        "type": "boolean",
+        "default": false,
+        "description": "Enable debug logging"
+      }
+    },
+    "required": ["mode"]
+  }
+}
diff --git a/pi_wake_agent.skill.yaml b/pi_wake_agent.skill.yaml
new file mode 100644
index 00000000..9935c7af
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+++ b/pi_wake_agent.skill.yaml
@@ -0,0 +1,242 @@
+# pi_wake_agent Skill Definition
+# Universal Agent Skill Format (YAML)
+# Compatible with: Anthropic, LangChain, OpenAI Functions, Custom Agents
+
+skill:
+  name: "pi_wake_agent"
+  version: "1.1.0"
+  description: |
+    Multi-agent wake-up timer with self-cron/daemon/succession modes.
+    Sends doorbell injections via zellij and durable messages via h5i bus.
+    Designed for the DOLPHIN fleet (pi_nvnemo, cmd, mimo, codex, etc.).
+
+  author: "pi_nvnemo"
+  repository: "https://github.com/dolphinng5/pi_wake_agent"
+  branch: "tools/pi_wake_agent"
+  license: "MIT"
+
+  # ─── Installation ─────────────────────────────────────────────────────
+  installation:
+    method: "script"
+    path: "/mnt/dolphinng5_predict/pi_wake_agent.py"
+    requirements:
+      - python >= 3.8
+      - zellij (for terminal injections)
+      - h5i (for bus messaging, optional)
+    test_command: "python3 -m pytest test_pi_wake_agent.py -v"
+
+  # ─── Capabilities ─────────────────────────────────────────────────────
+  capabilities:
+    - name: "install_cron"
+      description: "Install recurring wake-up timer via system cron"
+      modes: ["install"]
+    - name: "once"
+      description: "One-shot wake after interval (no cron)"
+      modes: ["once"]
+    - name: "daemon"
+      description: "Long-lived process, no cron needed"
+      modes: ["daemon"]
+    - name: "succession"
+      description: "Run N times at interval, then self-clean (remove cron)"
+      modes: ["succession"]
+    - name: "run_wake"
+      description: "Internal: execute wake action (called by cron)"
+      modes: ["run"]
+    - name: "remove_cron"
+      description: "Remove cron timer entry"
+      modes: ["remove"]
+    - name: "list_cron"
+      description: "List active cron timers"
+      modes: ["list"]
+    - name: "status"
+      description: "Show cron + one-shot timer status"
+      modes: ["status"]
+    - name: "validate_sessions"
+      description: "Validate zellij sessions exist"
+      modes: ["validate"]
+
+  # ─── Parameters ───────────────────────────────────────────────────────
+  parameters:
+    mode:
+      type: "string"
+      enum: ["install", "once", "daemon", "succession", "run", "run", "remove", "list", "status", "validate"]
+      required: true
+      default: "install"
+      description: "Operation mode"
+
+    interval:
+      type: "string"
+      pattern: "^\\d+[hms]$"
+      default: "1h"
+      description: "Interval duration. Formats: 30m, 1h, 90m, 2h, 10s"
+      examples: ["1h", "30m", "90m", "2h", "10s"]
+
+    session:
+      type: "array"
+      items:
+        type: "string"
+      description: "Zellij session name(s). Repeatable flag."
+      examples: [["cc_UV_dev0_Fb"], ["cc_UV_dev0_Fb", "cc_UV_dev1_48"]]
+
+    sessions:
+      type: "string"
+      description: "Comma-separated list of sessions (alternative to --session)"
+      examples: ["cc_UV_dev0_Fb,cc_UV_dev1_48"]
+
+    message:
+      type: "string"
+      default: "Operator says CONTINUE. pi_nvnemo here, saying hi!"
+      description: "Wake message sent to agent(s)"
+
+    count:
+      type: "integer"
+      minimum: 1
+      default: 1
+      description: "Number of runs for succession mode"
+
+    dry_run:
+      type: "boolean"
+      default: false
+      description: "Show what would be done without executing"
+
+    debug:
+      type: "boolean"
+      default: false
+      description: "Enable debug logging"
+
+    json:
+      type: "boolean"
+      default: false
+      description: "Output JSON for machine parsing"
+
+    config:
+      type: "string"
+      description: "Path to config file (JSON/YAML)"
+
+  # ─── Returns ──────────────────────────────────────────────────────────
+  returns:
+    type: "object"
+    properties:
+      exit_code:
+        type: "integer"
+        description: "0 = success, non-zero = error"
+      cron_entry:
+        type: "string"
+        description: "Installed cron line (for install mode)"
+      log_file:
+        type: "string"
+        value: "/tmp/pi_wake_agent.log"
+      message_sent:
+        type: "boolean"
+        description: "Whether wake message was sent"
+
+  # ─── Side Effects ─────────────────────────────────────────────────────
+  side_effects:
+    - "Modifies system crontab (install/remove modes)"
+    - "Injects text into zellij sessions (zellij write-chars)"
+    - "Sends h5i bus message to Fable (fire-and-forget)"
+    - "Writes to /tmp/pi_wake_agent.log (rotated at 10MB)"
+    - "Creates PID files in /tmp/pi_wake_agent_*.pid (once mode)"
+
+  # ─── h5i Bus Protocol ─────────────────────────────────────────────────
+  bus_protocol:
+    agent_id: "pi_nvnemo"
+    target: "Fable"
+    message_format: "[pi_nvnemo via zellij] {message} Run: h5i-bus msg inbox"
+    keypresses: 5
+    keypress_delay_ms: 1000
+    bus_message: "{message} (timer wakeup)"
+    timeout_ms: 5000
+    fire_and_forget: true
+    silently_ignore_failures: true
+
+  # ─── Zellij Integration ───────────────────────────────────────────────
+  zellij:
+    command_check: "zellij list-sessions"
+    injection_method: "zellij --session {session} action write-chars"
+    enter_keypress: "zellij --session {session} action write 13"
+    ansi_strip: true
+    session_exists_check: true
+
+  # ─── Cron Format ──────────────────────────────────────────────────────
+  cron:
+    comment_format: "pi_wake_agent:{sessions}:{interval}"
+    session_delimiter: ","
+    command_template: "cd /mnt/dolphinng5_predict && export H5I_AGENT=pi_nvnemo && /mnt/dolphinng5_predict/pi_wake_agent.py --run --sessions '{sessions}' --msg '{message}'"
+
+  # ─── Logging ──────────────────────────────────────────────────────────
+  logging:
+    file: "/tmp/pi_wake_agent.log"
+    rotation_mb: 10
+    max_files: 5
+    format: "[YYYY-MM-DD HH:MM:SS] [LEVEL] message"
+    levels: ["DEBUG", "INFO", "WARN", "ERROR"]
+
+  # ─── Examples ─────────────────────────────────────────────────────────
+  examples:
+    - name: "Recurring 1-hour wake for one session"
+      command: "pi_wake_agent.py --install --interval 1h --session cc_UV_dev0_Fb"
+    - name: "Multi-session 30-minute wake"
+      command: 'pi_wake_agent.py --install --interval 30m --sessions "cc_UV_dev0_Fb,cc_UV_dev1_48" --msg "Wake up!"'
+    - name: "One-shot in 2 hours"
+      command: 'pi_wake_agent.py --once --interval 2h --session cc_UV_dev0_Fb --msg "Time\'s up!"'
+    - name: "Run 3 times at 1-hour intervals, then self-clean"
+      command: 'pi_wake_agent.py --succession --count 3 --interval 1h --session cc_UV_dev0_Fb --msg "Scheduled wake"'
+    - name: "Daemon mode (long-lived process, no cron)"
+      command: 'pi_wake_agent.py --daemon --interval 1h --session cc_UV_dev0_Fb'
+    - name: "Remove timer"
+      command: 'pi_wake_agent.py --remove --session cc_UV_dev0_Fb --interval 1h'
+    - name: "List / status"
+      command: "pi_wake_agent.py --list"
+      command: "pi_wake_agent.py --status"
+    - name: "Validate sessions exist"
+      command: 'pi_wake_agent.py --validate --session cc_UV_dev0_Fb'
+    - name: "Dry run (show what would happen)"
+      command: 'pi_wake_agent.py --install --interval 1h --session test --msg "test" --dry-run'
+
+  # ─── Error Handling ───────────────────────────────────────────────────
+  error_handling:
+    - condition: "missing_session"
+      action: "return_error"
+      message: "--session or --sessions required"
+      exit_code: 1
+    - condition: "invalid_interval"
+      action: "return_error"
+      message: "Invalid interval format. Use like 1h, 30m, 90m, 2h"
+      exit_code: 1
+    - condition: "invalid_count"
+      action: "return_error"
+      message: "--count must be >= 1 for succession mode"
+      exit_code: 1
+    - condition: "cron_failure"
+      action: "log_warning_continue"
+      description: "Cron install/remove logs warning but continues"
+    - condition: "zellij_not_found"
+      action: "log_warning_continue"
+      description: "Session injection fails silently, bus message still sent"
+    - condition: "h5i_timeout"
+      action: "silent_ignore"
+      description: "h5i bus message failures are silently ignored (fire-and-forget)"
+
+  # ─── Testing ──────────────────────────────────────────────────────────
+  testing:
+    test_file: "test_pi_wake_agent.py"
+    test_count: 38
+    coverage:
+      - unit_interval_parsing
+      - unit_cron_comments
+      - unit_session_parsing
+      - integration_install_remove_list
+      - integration_once_short
+      - integration_succession_short
+      - edge_cases_invalid_intervals
+      - edge_cases_missing_sessions
+      - edge_cases_invalid_counts
+    run_command: "python3 -m pytest test_pi_wake_agent.py -v"
+
+  # ─── Metadata ─────────────────────────────────────────────────────────
+  metadata:
+    created: "2026-07-08"
+    updated: "2026-07-08"
+    maintainer: "pi_nvnemo"
+    tags: ["wake-timer", "cron", "zellij", "h5i", "multi-agent", "doorbell", "self-cleaning"]