LinkedIn Poster

Use when you need to post content to LinkedIn, including text posts, image posts, and

LinkedIn Posting

Overview

Post text and images to LinkedIn via the message tool using the linkedin channel. Supports text-only posts, image posts (local files or URLs), and #BuildInPublic updates.

Prerequisites

The linkedin channel must be configured in channels.linkedin with:

• accessToken: OAuth 2.0 token with w_member_social scope
• personUrn: Your LinkedIn person URN (e.g. urn:li:person:Abc123)

Posting Text

Use the message tool to send a text post:

text

message send --channel linkedin --text "Your post content here"

The post goes to the authenticated user's LinkedIn feed as a public post.

Posting with Images

Two-step process:

1. Create the image — generate or locate the image file (PNG/JPG/GIF/WebP)
2. Post with image — use message send with the --media flag:

text

message send --channel linkedin --text "Post caption" --media /path/to/image.png

Supported image sources:

• Local file paths: /Users/david/image.png
• file:// URLs: file:///Users/david/image.png
• Remote URLs: https://example.com/image.png

Image Upload Flow (internals)

The extension handles a 3-step LinkedIn UGC API flow automatically:

1. Register upload → gets uploadUrl + asset URN
2. PUT binary to uploadUrl
3. Create UGC post with asset reference

You don't need to manage this — just provide the image path.

Best Practices

• Always confirm post content with the owner before posting
• Keep posts concise — LinkedIn favors 150-300 word posts
• Add hashtags at the end, not inline (3-5 max)
• For #BuildInPublic: include what you built, what you learned, a visual
• Image sizing: 1200x627px for link previews, 1080x1080 for square posts
• Never post without explicit owner approval

Post Templates

#BuildInPublic Update

text

🚀 [What you built today]

[2-3 sentences about what it does and why it matters]

Tech stack: [list]

[Screenshot or diagram]

#BuildInPublic #[topic] #[tech]

Project Milestone

text

✅ [Milestone achieved]

[Brief context — what, why, how]

Key learnings:
→ [Learning 1]
→ [Learning 2]
→ [Learning 3]

Next up: [what's coming]

#[project] #[topic]

Technical Deep-Dive

text

💡 TIL: [Thing you learned]

[Explanation in 2-3 paragraphs]

[Code snippet or diagram if relevant]

#TIL #[topic] #[tech]

Troubleshooting

Error	Cause	Fix
401 Unauthorized	Token expired	Re-authenticate, update channels.linkedin.accessToken
403 Forbidden	Missing w_member_social scope	Re-create OAuth app with correct scopes
Image upload 400	File too large (>10MB)	Compress image before uploading
Empty postUrn	API didn't return ID	Post likely succeeded — check LinkedIn feed