send-reply

# Send Reply Skill Send your final response to the user. This is the gateway to external communication. ## Critical Rules 1. **One reply only**: You can only send ONE reply. You MUST send exactly ONE reply. 2. **This is the ONLY external output**: All other processing remains internal. 3. **Timeout**: The script won't run for more than 30 seconds. If it hangs, do stop_bash. 4. **No second attempt**: If you fail to send the reply or if the script encounters an error, you won't get a second chance to send another reply. That means you failed your job. Make sure your message is final and well-crafted before executing this skill. 5. **Think before you send**: Take a moment to review your message for clarity, tone, and content. Once you hit send, there's no going back. 6. **Exit directly after sending the reply**: After executing this `send-reply` skill, you must exit immediately. Do not summarize, continue processing, or attempt to send another message. Your job is done. 7. **Threading**: The reply is threaded to the message the file tool (`send-file`) most recently delivered, when one exists in this session; otherwise it is threaded to the user's trigger message. ## Usage **Two-step flow — the message text MUST NOT appear on the command line.** 1. Write your reply text to a payload file under the session staging directory using your **edit/write tool**: ``` $TMPDIR/$SESSION_ID/reply.md ``` The `$TMPDIR` / `$SESSION_ID` tokens in that path are expanded by the ACP path boundary, so the write is approved and the text bytes are preserved **verbatim** (no shell expansion). `$TMPDIR/$SESSION_ID/` is the per-spawn form of the staging directory; in shared-process deployments the staging directory is shown in your system prompt and the script resolves it automatically. 2. Invoke the script with the payload file path: ```bash ${HOME}/.agents/skills/send-reply/scripts/send-reply.ts \ --session-id "$SESSION_ID" \ --message-file "$TMPDIR/$SESSION_ID/reply.md" ``` **WARNING**: Never put message content on the command line. The legacy `--message "..."` / `--message=...` flags are REMOVED: the shell expands `$VAR` in them (e.g. `$0` → `/usr/bin/bash`, `$HOME`, `$API_KEY`), which corrupts your message and can leak environment variables to the user. ## Parameters | Parameter | Required | Description | | ---------------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | `--session-id` | Yes | Use the session id rendered in your system prompt. `$SESSION_ID` works only in per-spawn deployments; in shared-process mode it is not set and the skill library resolves the owning session automatically — a mismatched value is never honored | | `--message-file` | Yes | Path of the payload file containing the reply text (must be under `$TMPDIR/$SESSION_ID/`) | ## Error Codes If the script fails, read the JSON error on stderr. It contains the fix. Common codes: | Code | Meaning | Fix | | ----------------------------- | ---------------------------------------------- | -------------------------------------------------------------------------- | | `SKILL_LEGACY_FLAG` | You used the removed `--message` flag | Put the text in `$TMPDIR/$SESSION_ID/reply.md` and use `--message-file` | | `SKILL_MISSING_PAYLOAD` | No `--message-file` given | Write the payload file first, then invoke with `--message-file` | | `SKILL_PAYLOAD_OUT_OF_BOUNDS` | Payload path is outside `$TMPDIR/$SESSION_ID/` | The script only reads its own session's staging dir — stage the text there | | `SKILL_PAYLOAD_NOT_FOUND` | Payload file missing/unreadable | Write the file FIRST with the edit/write tool, then invoke the script | ## Limits - Maximum **1 reply** per session. After sending the first reply, subsequent calls will be rejected. - If rejected, use `edit-reply` to modify the existing message instead. - Excessive retry attempts will cause the agent process to be terminated. - Ultrathink carefully and ensure you have all the text prepared before proceeding, as you may not get another chance.