X Tag Responder — Skill Reference
This skill activates when your human tags you (their AI familiar) in someone else's X/Twitter thread.
It fetches the full conversation, infers their intent, drafts a fitting reply, and handles X API
reply-chain restrictions.
Prerequisites
xurl CLI installed at /home/linuxbrew/.linuxbrew/bin/xurl (or on PATH as xurl)- Config at
~/.xurl with valid OAuth1 or OAuth2 credentials
- Never read, print, or expose
~/.xurl contents to the LLM context
Trigger Patterns
This skill is relevant when the user says things like:
- "I tagged you in a tweet / thread"
- "Check out this tweet I tagged you in"
- "Weigh in on this" (with a tweet URL or ID)
- "Reply to this for me" (with context)
- They paste a tweet URL or ID and imply the agent should respond
Step-by-Step Workflow
Step 1 — Identify the Tagged Tweet
Extract the tweet ID or URL from the user's message. It will look like:
https://x.com/username/status/1234567890https://twitter.com/username/status/1234567890- A bare numeric ID like
1234567890
If unclear, ask the user: "What's the tweet URL or ID you tagged me in?"
Step 2 — Fetch the Tagged Tweet
Read the tweet the human tagged you in:
xurl read TWEET_ID
This returns full tweet data including: text, author_id, conversation_id, in_reply_to_user_id, referenced_tweets.
Note the conversation_id — it identifies the root of the thread.
Step 3 — Fetch Thread / Conversation Context
Pull the broader conversation using the conversation_id from Step 2:
xurl search "conversation_id:CONVERSATION_ID" -n 20
This retrieves recent tweets in the thread. Sort mentally by id (ascending = chronological).
Build a mental model of:
- Who started the thread and what they said
- What the thread is about (topic, tone, stance)
- Where the tagged tweet sits in the conversation
- What the human's tagged tweet says (their cue to you)
Step 4 — Infer Human Intent
Read what the human wrote when they tagged you. Infer one of these intents:
| Cue in tag tweet | Likely intent |
|---|
| "What do you think?" / "Thoughts?" | Weigh in with a take |
| "Reply to this" / "Handle this" | Draft a reply on their behalf |
| "Is this true?" / "Fact-check" | Research and report back (don't post) |
| "lol check this out" | Just read/acknowledge, probably no reply needed |
| No cue text — just a tag | Ask the human what they want |
| "@agent check the math" | Analyze/verify, reply if appropriate |
When uncertain, default to: draft a reply and ask the human to approve before posting.
Step 5 — Draft the Reply
Craft a reply that:
- Matches the tone of the thread (technical → precise; casual → relaxed; debate → grounded)
- Stays concise (X has a 280-char limit; aim under 240 to leave room for context)
- Speaks as the agent or for the human — whichever the intent implies
- Does not start with "I" (Twitter convention + feels robotic)
- Does not use hollow filler like "Great point!" unless it's sarcastic and earned
Present the draft to the human for review before posting:
"Here's a draft reply. Should I post it?
[DRAFT TEXT]"
Step 6 — Post the Reply (with Human Approval)
Once the human approves:
xurl reply TWEET_ID "Your reply text here"
Where TWEET_ID is the ID of the specific tweet you are replying to (usually the tweet the human tagged you in, or the thread root if instructed).
⚠️ X API Reply-Chain Restriction
The X API only allows you to reply to a tweet if your account is mentioned somewhere in the reply chain.
This means:
- If the thread is between two other users and you are not already in it,
xurl reply will fail with a 403 or silently not thread correctly.
- The tagged tweet (where your human mentioned you) creates your entry point — you CAN reply to that tweet.
- You cannot reply to arbitrary tweets in the thread that don't mention you.
Handling the Restriction
If reply succeeds: Report back with the posted tweet URL.
If reply fails (403 / authorization error / "not allowed"):
Report back clearly:
"I can't reply directly to that tweet — I'm not in the reply chain. Here's what I'd say though:
[DRAFT TEXT]
Options:
- Tag me directly in the specific tweet you want me to reply to — that adds me to the chain.
- You post the reply yourself and I'll write it for you.
- I can quote-tweet instead (no chain restriction): just confirm."
Offering a quote-tweet fallback:
xurl quote TWEET_ID "Your reply text here"
Quote-tweets bypass the reply-chain restriction entirely.
Error Reference
| Error | Meaning | Fix |
|---|
| 403 Forbidden | Not in reply chain | Report + suggest re-tag or quote-tweet |
| 401 Unauthorized | Auth expired | Run xurl auth status; re-auth if needed |
| 429 Too Many Requests | Rate limited | Wait ~15 min and retry |
| Tweet not found | Deleted or private | Tell the human the tweet is inaccessible |
Full Example Session
Human says:
"I tagged you in this tweet — weigh in: https://x.com/someuser/status/9876543210"
Agent workflow:
# 1. Read the tagged tweet
xurl read 9876543210
# → Note: conversation_id=1111111111, text="@quirk what do you think of this?", author=human
# 2. Fetch thread context
xurl search "conversation_id:1111111111" -n 20
# → Read thread: original author debating AI regulation, 5 replies
# 3. Infer intent: "What do you think?" → weigh in
# 4. Draft reply (280 chars max):
# "Regulation works best when it's targeted at outcomes, not methods.
# Banning specific architectures is a game of whack-a-mole —
# but liability frameworks? That actually scales. 🧵"
# 5. Present to human for approval
# 6. Post if approved:
xurl reply 9876543210 "Regulation works best when it's targeted at outcomes, not methods. Banning specific architectures is whack-a-mole — but liability frameworks scale. 🧵"
Tips
- Read before you write. Always fetch the full thread before drafting. Context is everything on X.
- Match the register. A shitpost thread and a policy debate are not the same. Sound like you belong.
- Short > long. Twitter threads reward punchy. If you need more space, thread it.
- Always confirm before posting. Unless the human explicitly says "just post it," show the draft first.
- Quote-tweet is always available. When in doubt, quote-tweet bypasses all chain restrictions.
Security Notes
- Never print or expose
~/.xurl — it contains API keys and tokens.
- Never use
--verbose / -v in agent sessions — can expose auth headers.
- Always confirm with the human before posting publicly on their behalf.
- Credentials are handled by
xurl internally; do not pass tokens as CLI flags in agent context.
