X (Twitter) Algorithm Playbook

How the X "For You" feed ranks posts, based on xAI's open-sourced algorithm (xai-org/x-algorithm, May 2026 release — the Phoenix ranker and Grox content-understanding pipeline), and what to change in your posting practice because of it.

Sourcing note: the release publishes the ranking structure (which signals are scored and how they combine) but not the weight values (params.rs is withheld). Rules below are tagged [verified] when the mechanism is visible in the code, [reported] when the specific number or magnitude comes from secondary analysis of the release. Structure changes slowly; reported numbers age fast — treat them as directionally true.

How ranking works (60-second version)

1. Candidate posts come from two sources: accounts the viewer follows (Thunder) and ML-retrieved posts from the global corpus (Phoenix retrieval). You are always competing for out-of-network reach, not just your followers' feeds.
2. Filters remove ineligible posts before scoring: too old, already seen or served, muted keywords, blocked/muted authors.
3. The Phoenix transformer predicts a probability for each engagement type — not one "quality score" but ~15 separate predictions.
4. Final score = weighted sum of those probabilities. Positive actions add; predicted negative actions (not-interested, mute, block, report) subtract.
5. An author-diversity scorer then decays the scores of repeated authors within a feed response, so your posts compete with each other.

The model has no hand-engineered "quality" features — it learns entirely from engagement histories. You can't optimize for the algorithm directly; you optimize for the specific behaviors it predicts. And notice what those behaviors are: staying to read, sending to a friend, following the author, joining the conversation. Those are the things a well-told story produces. Storytelling and genuine connection with your audience aren't a separate strategy from the mechanics below — they're what the mechanics reward. The rules tune distribution; the story earns the engagement.

The signals your post is scored on [verified]

Every signal below is a separate weighted term in the scoring code:

The 10 rules

1. Open with a specific claim in the first 8 words. [reported] Dwell is scored two ways [verified], and scroll-past is the dwell-killer. Don't warm up — the hook is the post.

2. Wait ~60 minutes between original posts. [reported number] The author-diversity scorer is verified: within a feed response, each additional post from the same author gets a decayed score. Clustered posts cannibalize each other's reach.

3. Name your topic in the first 10 words. [reported] Topic-based candidate sourcing and followed-topic hydration are verified in the pipeline — the algorithm routes posts to topic followers, but only if it can tell what the topic is. Vague musings don't get routed.

4. Write for the DM-forward, not the like. [verified structure; relative weight reported] Share-via-DM is its own scored signal. The test for every post: "would someone send this to a friend?" beats "would someone like this?"

5. Quote tweets score twice. [verified structure] Quote engagement and quoted-click are separate terms. Quoting with added insight beats plain reposting — for both parties.

6. Write for the follow. [verified structure] Follow-author is a distinct signal. Posts that make a stranger think "I want more of this" outperform posts that make them think "ha, nice."

7. Make them curious enough to click your profile. [verified structure] Profile clicks are scored. This is the mechanical argument for a strong bio and pinned post: the algorithm rewards posts that trigger the click, and your profile converts it.

8. Name specific things. [verified mechanism] Two reasons: specificity is what enables topic routing (rule 3), and the muted-keyword filter removes posts pre-scoring — generic engagement-bait phrases are commonly muted; specific nouns ("Claude", "Stripe") rarely are.

9. Video must clear the minimum duration — with captions. [verified mechanism; ~8s reported] The video-quality-view weight only applies above MIN_VIDEO_DURATION_MS. Below the threshold, video earns zero video credit. Captions serve the dwell signals (most viewing is muted).

10. Be present for the first 30 minutes. [reported] Early replies compound: each reply you answer is a fresh engagement event, and reply chains feed the dwell and conversation signals. Post when you can stay, not when the scheduler fires.

What kills reach [verified]

• Muted keywords — filtered before scoring even happens. Spammy CTA phrases and rage-bait vocabulary are widely muted.
• Predicted negative actions — if your post pattern-matches to content people block, mute, or hit "not interested" on, it's penalized before anyone acts. Engagement bait doesn't just annoy humans; it's a modeled negative.
• Posting bursts — author-diversity decay (rule 2). Your second post in an hour starts handicapped.
• Already-seen content — reposting the same content quickly hits the previously-seen/served filters. Evergreen reruns need spacing.

Caveats

• Weights are unpublished. Claims like "shares are worth N× likes" are inference, not source. The safe conclusion is which behaviors are scored at all — and that private shares, follows, profile clicks, and dwell each matter independently.
• This ages fast. The repo gets updated releases; if you're reading this long after May 2026, check xai-org/x-algorithm for changes before treating numbers as current.
• These rules are X-specific. The general principles (hook early, specificity, reply presence) travel to other platforms; the mechanics (60-minute spacing, quote-double-counting, video minimums) do not.