Social Media Content skill for Codex

Social content is done well when each post is written for the platform it appears on (length, format, culture), opens with a line that earns the next one, carries one idea, and the calendar is built from a few pillars the audience actually cares about. Posting the same text everywhere is not distribution.

Inputs

• Who the account speaks as (founder, company, product) and the brand voice; check the repo or docs for a voice guide (rg -il "voice|tone" docs/ content/), or use brand-voice.
• The audience per platform and the goal: followers, clicks to a page, signups, hiring, community. One goal per post.
• Source material: blog posts, changelogs, docs, talks, customer stories, data. Original material beats commentary.
• Past performance export if available (CSV from LinkedIn, X, Meta Business Suite).

Platform specifics

Limits change; confirm in the platform UI when a number matters.

Platform	Text limit	What works	Watch out
LinkedIn	3,000 chars; ~2-3 lines show before “see more”	First-person lessons, specific numbers, carousels (PDF documents), short paragraphs	Engagement-bait (“Comment YES”), walls of hashtags
X	280 chars (longer for paid accounts)	One sharp claim, threads that deliver on the first post, native images and video	Threads where post 1 is only “A thread:”
Threads	500 chars	Conversational, replies matter	Cross-posted X jargon
Bluesky	300 chars	Developer and niche communities, custom feeds	Links work; keep the post useful without them
Instagram	2,200-char captions; max 5 hashtags per post (cap introduced late 2025)	Reels (9:16), carousels (4:5), first line of caption	Text-heavy single images
TikTok / YouTube Shorts / Reels	Video-first; script the first 2 seconds	Hook on screen + spoken, captions burned in, 15-45 s	Slow intros, logo animations
Reddit	Per-subreddit rules	Genuine contributions, answers, behind-the-scenes	Self-promotion; read each subreddit’s rules and promotion ratio first

Hand video production to a video skill; this skill writes the script and on-screen text.

Workflow

- [ ] 1. Define 3-5 content pillars and the goal per platform
- [ ] 2. Inventory source material; pick the pieces with the most original insight
- [ ] 3. Draft posts per platform from each source (repurposing matrix below)
- [ ] 4. Edit: hook, one idea, specifics, CTA matching the goal
- [ ] 5. Add alt text, captions, link tracking
- [ ] 6. Lay out the calendar; export in the scheduler's import format
- [ ] 7. After 2-4 weeks, review performance and adjust pillars and formats

Content pillars

Each pillar is a theme the account can speak on with authority plus a reason the audience cares. Example for a developer tool:

Pillar	Share of posts	Example formats
Hard-won engineering lessons	35%	LinkedIn story post, X thread, blog excerpt
Product in use (not features)	25%	30 s screen recording, before/after
Customer and community	20%	Customer quote with result, community highlight
Industry point of view	15%	Opinion post with a specific claim
Company / hiring / behind the scenes	5%	Team photo with context, hiring post

Repurposing one source

From one blog post or release:

1. LinkedIn: the core lesson as a first-person story, 150-250 words, no link in the body if testing reach (put it in the first comment, then compare results).
2. X thread: 4-7 posts; post 1 states the payoff, each post stands alone, last post links.
3. Carousel: 6-10 slides, one point per slide, big type, last slide CTA.
4. Short video: 30 s script showing the result on screen.
5. 3-5 single posts quoting distinct insights, spaced across weeks.

Writing rules

• Hook (first line): a specific claim, number, contrarian take, or concrete scene. “We cut our CI time from 22 to 6 minutes. 3 changes did 80% of it.” beats “Excited to share some thoughts on CI.”
• One idea per post. If there are three ideas, that is three posts or a thread.
• Specifics over adjectives: numbers, names (with permission), screenshots, code.
• White space: short paragraphs on LinkedIn; one sentence per line where it aids reading.
• CTA matches the goal: a question for discussion, a link for traffic, nothing for reach-building posts. One CTA.
• Hashtags: 0-3 relevant ones on LinkedIn and X; up to 5 on Instagram. No generic tags.
• Mentions: tag people only when they are part of the story and would welcome it.
• No engagement bait, no fake urgency, no claims you could not back up in the replies.

Accessibility

• Alt text on every image: what it shows and why it matters, under ~250 characters. For charts, state the takeaway (“Build time fell from 22 to 6 minutes after…”).
• Burned-in captions on all video; most viewers watch muted.
• Use CamelCase in multi-word hashtags (#OpenSource) so screen readers pronounce them.
• Avoid stylised Unicode “bold” fonts; screen readers read them letter by letter.

Calendar and scheduling

Keep the calendar as a CSV or sheet the user can import. Columns:

date,time_local,platform,pillar,format,hook,body,asset,alt_text,link,utm_campaign,status
2026-11-03,09:00,linkedin,engineering-lessons,text,"We cut CI from 22 to 6 minutes.","...",,,"https://acme.dev/blog/ci?utm_source=linkedin&utm_medium=social&utm_campaign=ci-post",ci-post,draft

• Cadence the team can sustain beats a burst: e.g. LinkedIn 3x/week, X daily, video 1-2x/week.
• Post in the audience’s working hours; test two time slots before trusting “best time” lists.
• Tag links with UTMs (utm_medium=social) per utm-attribution, so traffic shows up correctly.

Scheduling and publishing go out under the user’s name or brand and cannot be fully recalled. Prepare drafts and the import file; publish or schedule only after the user approves the final text for each post.

Reviewing performance

From platform exports, compare by pillar and format, not by individual post:

Metric	Use for
Engagement rate (engagements / impressions)	Content quality signal across accounts of different size
Saves, shares, reposts	Strongest signal of value
Profile visits, follows per post	Audience growth
Clicks and downstream signups (UTM in GA4/PostHog)	Business impact

Double down on the top pillar/format pairs, cut the bottom ones, and keep 20% of posts experimental.

Gotchas

• Copying a LinkedIn post to X and truncating it mid-sentence.
• Threads whose first post promises more than the thread delivers.
• Posting customer names, logos or screenshots of customer data without permission.
• Scheduling posts during an incident or sensitive news; pause the queue.
• Measuring only likes; they correlate weakly with signups.

Verification

• Every post fits its platform’s limit and reads correctly in the platform’s preview.
• Each image has alt text, each video has captions.
• Links resolve and carry UTMs; test one from the scheduled post.
• The calendar covers the period without gaps longer than the planned cadence.

Output template

## Social plan: <account>, <period>
**Goal per platform:** ...
**Pillars:** table with share of posts
**Calendar:** CSV attached (N posts)
### Sample posts
**LinkedIn - <pillar>**
<post text>
Alt text: ...
**X thread - <pillar>**
1/ ...
**Awaiting approval before scheduling:** all posts