# Cross Session Message > Preview or send a bounded instruction into another known live zellij-backed coding-agent session or Codex Desktop thread outside Symphony. - Skill: `ma08/cross-session-message` (Agent Skill) - Install (CLI): `npx skillmds@latest add ma08/cross-session-message` - Raw SKILL.md: https://api.skillmd.com/api/skills/ma08/cross-session-message/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: ma08 (https://skillmd.com/u/ma08) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/ma08/cross-session-message --- # Cross-Session Message Use the repo-managed `send-zellij-message` helper when the user wants to nudge another live zellij-backed task/session with a bounded instruction. When running inside Codex Desktop and the target is a Codex Desktop thread, use the app thread tools as the Desktop transport. For UI-only work routed to the Mac in-app Browser or native Computer Use, use `mac-ui-worker` instead of treating a generic cross-session message as a UI-job protocol. Within an accepted Mac UI job, do not use this skill to relay routine clarification, login, MFA, credential entry, approval, or handoff between the worker and source. Those checkpoints stay between Sourya and the worker by default. The only approval exception is an exact, visibly pre-declared, single-use source delegation. Cross-task sends must match a callback, dependency result, correction, cancellation, or terminal receipt allowed by the complete initial `mac-ui-worker/v1` envelope. ## Invocation ```text $cross-session-message /cross-session-message ``` ## Command ```bash send-zellij-message --project-root "" --text "" ``` Useful flags: - `--execute` - `--submit enter` - `--tab-name ` - `--replace-claude-suggestion` - `--json` Codex Desktop thread path, when `codex_app` tools are available: 0. If the thread tools are not already visible, use the runtime's tool discovery to load `list_threads`, `read_thread`, and `send_message_to_thread`. 1. Use `list_threads` with the tracker id, task slug, or visible title. 2. If the result is ambiguous, stop and surface the candidates. 3. Use `read_thread` if you need to confirm the current target state. 4. Send with `send_message_to_thread`, passing `threadId` and `hostId`. 5. Omit `model` and `thinking` unless the user explicitly asks to override the destination thread's settings. ## Behavior - Run the preview first. The helper is dry-run by default. - Add `--execute` only after the resolved session/tab target looks correct. - Use `--submit enter` only when you intentionally want the target session to receive Enter after the text write. - The preview resolves one supported Claude Code or Codex pane and inspects its composer without mutation. An unsafe, non-empty, busy, ambiguous, or unsupported composer blocks execution. - Claude Code autocomplete is a narrow exception only with explicit `--replace-claude-suggestion`. The helper requires visible suggestion text while the cursor remains at the empty-prompt position. A flagged preview reports `preview_probe_required`; execution sends a non-text end-of-line cursor probe. A real buffered draft moves the cursor, is restored without changing text, and fails closed. Only an empty buffer behind autocomplete may proceed. - Execution writes only to the resolved pane id. It verifies staging before any Enter, and reports `delivered: true` only after the staged text is observed as a new agent turn. - Receipts distinguish `preview_safe`, `preview_unsafe`, `unsafe_composer`, `staged`, `delivered`, and `unverified`. `executed: true` means a mutation was attempted; it does not mean delivery. Gate follow-through on `outcome: delivered` and `delivered: true`. - Long or multiline Codex prompts receive a delayed confirm Enter only when the intended payload is still visibly staged after the first Enter. - Stop on ambiguous tab selection, cross-machine targets, or missing tracked session data unless the user is intentionally doing local debug work with an explicit `--zellij-session`. - If a non-interactive shell lacks `XDG_RUNTIME_DIR`, the helper keeps an active default zellij namespace. When that namespace has only a missing or exited target and `/run/user/` has the exact live session, it selects the live systemd namespace and records that choice in the receipt. It never switches away from an active default target. - Explicit-session debug sends may identify a uniquely supported wrapped Claude or Codex UI from a read-only screen fingerprint when process-command metadata is unavailable. Ambiguous or multiple matches fail closed. - For Codex Desktop threads, the preview step is target resolution and, when useful, `read_thread`; `send_message_to_thread` is the actual send. - If no zellij session exists but a unique Codex Desktop thread is found, the Desktop path is valid and should not be treated as a zellij failure. - Codex CLI and Claude Code do not automatically have Codex Desktop thread tools. If `codex_app` tools are unavailable, do not edit SQLite state or local logs to simulate a human prompt. Use zellij if the target is terminal-backed, or ask the user to send from a Codex Desktop thread / provide an explicit supported bridge. - Use this for bounded prompt delivery, status pings, or resumable instructions only. It is not a remote-control channel. - A `mac-ui-worker/v1` request must use the exact recorded source and worker IDs, a unique job ID, exactly one declared surface, and the protocol envelope. Do not send UI jobs by title or to a shared worker guessed from history. - A later generic message cannot broaden an active Mac UI job. Value-safe corrections use the exact protocol correction envelope; material expansion requires a new complete request and job ID. ## Manual fallback If the helper reports an unsafe or unverified composer, stop automated sends. Attach to the resolved session, inspect the exact agent pane, and let the human decide how to handle any existing draft, selector, or unknown UI state. Do not clear it, append a retry, or send Enter through the helper. After the composer is manually returned to a visibly empty supported state, start again with a fresh preview. If the human confirms that Claude's visible text is autocomplete rather than a real draft, repeat the preview with `--replace-claude-suggestion`. Require `preview_probe_required`, then execute with the same flag. Execution may stage text only after `suggestion_probe: verified_empty_buffer` and `composer_preflight: safe_claude_suggestion_override`. Keep the message short enough for the whole staged payload to remain visible and verifiable. If staging is unverified, do not send Enter. See `~/pro/botfiles/docs/cross-session-orchestration-contract.md` for the shared contract.