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.

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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

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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

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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/1234567890
• https://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?"

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Step 2 — Fetch the Tagged Tweet#

Read the tweet the human tagged you in:

bash

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.

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Step 3 — Fetch Thread / Conversation Context#

Pull the broader conversation using the conversation_id from Step 2:

bash

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)

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Step 4 — Infer Human Intent#

Read what the human wrote when they tagged you. Infer one of these intents:

Cue in tag tweetLikely 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 neededNo cue text — just a tagAsk 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.

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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]"

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Step 6 — Post the Reply (with Human Approval)#

Once the human approves:

bash

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).

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⚠️ 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:

1. Tag me directly in the specific tweet you want me to reply to — that adds me to the chain.
2. You post the reply yourself and I'll write it for you.
3. I can quote-tweet instead (no chain restriction): just confirm."

Offering a quote-tweet fallback:

bash

xurl quote TWEET_ID "Your reply text here"

Quote-tweets bypass the reply-chain restriction entirely.

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Error Reference#

ErrorMeaningFix403 ForbiddenNot in reply chainReport + suggest re-tag or quote-tweet401 UnauthorizedAuth expiredRun xurl auth status; re-auth if needed429 Too Many RequestsRate limitedWait ~15 min and retryTweet not foundDeleted or privateTell the human the tweet is inaccessible

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Full Example Session#

Human says:

"I tagged you in this tweet — weigh in: https://x.com/someuser/status/9876543210"

Agent workflow:

bash

# 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. 🧵"

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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.

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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.