Build a Social Media Content Calendar with Claude Cowork

Claude Cowork can build and schedule your whole social media content calendar from the files on your computer: point it at a folder of notes, a launch doc or a set of screenshots, and with the PostAxis connector it plans the posts, validates them against each network's rules and schedules them after you approve. You add PostAxis once to your Claude account and every Cowork task can use it. This guide is for people whose content already lives in documents and folders, and who would rather hand over "fill the month" than write posts one by one.

What you can automate with Claude Cowork

Cowork is the mode in the Claude desktop app where Claude works through longer, multi-step tasks with access to the files and folders you choose. That makes it a different tool from a quick chat. It is suited to jobs with many steps and real source material:

• A folder into a week. Read the launch notes in a folder and schedule a week of X and LinkedIn posts from them.
• A 30-day calendar. Plan a month across X, LinkedIn and Threads, validate every post, show you the calendar, schedule after approval.
• Screenshots into a carousel. Turn a folder of product screenshots into an Instagram carousel for Friday evening.
• Gap filling. Check what is already scheduled next week and fill only the empty days.
• Weekly review. Report which posts published and which failed, then reschedule the failed ones.

What you need

• A PostAxis account. Every plan starts with a 7-day free trial and includes MCP access with OAuth sign-in.
• Your social accounts connected under Accounts in PostAxis.
• The Claude desktop app with Cowork available on your plan. Cowork uses the same connectors as the rest of Claude, which need a paid Claude plan.
• A folder with your source material: notes, docs, a brand guide, images.

How to connect Claude Cowork to PostAxis (step by step)

1. Create your PostAxis account at app.postaxis.io.
2. Connect your social accounts. Open Accounts in PostAxis and connect the networks you post to. Cowork can only post to accounts connected here, and never sees their passwords.
3. Add the PostAxis connector in Claude. Open the Claude desktop app → Settings → Connectors → Add custom connector. Name it PostAxis and paste the URL. If you already added PostAxis for regular Claude chats, skip this step: Cowork uses the same connectors.

https://postaxis.io/api/mcp

4. Connect and approve. Click Connect next to PostAxis, sign in to PostAxis and click Approve.
5. Start a Cowork task. Switch to Cowork in the Claude desktop app and give it access to the folder with your notes or images, if the task needs files.
6. Check it works. Start with a small task:

List the social accounts you can post to in PostAxis, and tell me what is
already scheduled for the next 7 days.

Cowork calls list_accounts and list_posts and reports back. If both work, the connection is good. When you give it a real task, Cowork shows its plan and asks before creating posts.

5 workflows you can copy

Turn a launch folder into a scheduled week

The core Cowork workflow. Keep everything about a launch in one folder (the announcement draft, the feature list, a few customer quotes you are allowed to share) and let Cowork read it all.

Read everything in ~/Documents/launch-oct. Build a week of posts for X
and LinkedIn, one each per weekday at 10:00 Europe/Berlin, starting next
Monday. Monday announces the launch, Tuesday to Thursday each cover one
feature, Friday is a recap with the sign-up link. Validate the whole plan,
show it to me as a table, and schedule only after I say go.

Cowork reads the files, drafts five posts with an X and a LinkedIn caption each, calls get_platform_rules, then create_posts_bulk with validate_only=true. PostAxis checks every caption and saves nothing. After you say go, Cowork repeats the call for real. You get something like: "Scheduled 5 posts (10 captions), one X and one LinkedIn per weekday at 10:00. Everything passed the rules check."

Fill a 30-day calendar from a content brief

When you have a brief or a list of themes and want the whole month planned. Cowork can send up to 50 posts in one bulk call, so 30 days fits in a single call.

Use content-brief.md and brand-voice.md in this folder. Plan 30 days of
posts for X, LinkedIn and Threads starting 1 November, one post a day
at 9:30 America/New_York, no posts on Sundays. Save the plan to
november-calendar.md in this folder first. Then validate everything in
PostAxis, list any problems, and schedule after I approve.

This is where Cowork earns its place: it works through the brief, writes a calendar file you can open and edit, then validates with create_posts_bulk and validate_only=true. If you change the file, ask it to re-read the file and validate again before scheduling. The posts land in your PostAxis calendar, where you can still edit any of them.

Make an Instagram carousel from a folder of screenshots

Instagram posts need images or a video, and PostAxis does not create them. Cowork can work with the screenshots you already have.

The folder ~/Desktop/v3-screens has 6 product screenshots. Pick the 5
that best explain the new dashboard, put them in a sensible order, and
schedule them as one Instagram carousel for Friday 18:00 Europe/London.
Caption: two short paragraphs and three hashtags.

Cowork looks at the images and picks the order. To get local files into PostAxis it uses create_upload_link, which returns a one-time upload link per file. Depending on what the task can do on your machine, Cowork either uploads through those links or gives them to you to upload; if the images are already online, it uses upload_media_from_url instead. It then schedules one post with create_post. Instagram allows 1 to 10 images per post, and the account must be a professional account.

Fill only the empty days next week

Useful when a teammate has already scheduled some posts and you just want the gaps covered.

Check what's scheduled in PostAxis for next week. For every weekday with
nothing on LinkedIn, write a post from the ideas in ideas.md and schedule
it at 11:00 Europe/Paris. Don't touch existing posts. Save new ones as
drafts so my colleague can review them.

Cowork calls list_posts for the date range, works out which days are empty, writes the missing posts and creates them as drafts with create_post. The drafts show up under Drafts in PostAxis for your colleague.

Review the week and fix failures

Run this on Friday. Publishing sometimes fails for reasons outside your control, such as a disconnected account.

Tell me which posts published this week and which failed, with the reason
for each failure. Reschedule the failed ones for tomorrow at 10:00
Europe/Berlin, and write a short summary to week-review.md.

Cowork calls list_posts by status and date range, then get_post on each failure to read its per-network status, uses update_post to move them to tomorrow, and writes the summary file. If a failure was caused by a disconnected account, reconnect it under Accounts in PostAxis before the new time.

Network limits Claude Cowork works within

Videos must be MP4 or MOV, 3 to 300 seconds, in 16:9, 9:16, 4:3, 3:4 or 1:1, and a post cannot mix images and video. PostAxis checks all of this before saving anything, which matters for a long task: a 30-post batch with one bad caption gets flagged during validation, not discovered the morning it fails to publish.

Tips for better posts

• Keep a brand-voice file in the folder. A short brand-voice.md with your audience, tone, banned words and two or three example posts gives Cowork something concrete to follow on every task. Mention it by name in your prompt.
• Validate first, every time. For a long task, ask Cowork to validate the whole plan before scheduling. It costs nothing and saves nothing until you approve.
• Say the timezone. "10:00 Europe/Berlin", not "10 am". Without one, Cowork uses whatever timezone it was told or UTC.
• Ask for a file you can edit. Having Cowork write the plan to a markdown file before scheduling gives you a readable record and an easy place to make changes.
• Use drafts when someone else approves. Drafts appear under Drafts in PostAxis, where a teammate can edit and schedule them.
• Give only the folders the task needs. Cowork works with the files you choose. A dedicated content folder keeps it focused and keeps unrelated files out of the task.

Troubleshooting

• Cowork says no accounts are connected. Connect at least one account under Accounts in PostAxis. With several workspaces, name one: "use my Acme workspace".
• 401 Unauthorized or "sign in again". The sign-in expired or was revoked. In the Claude desktop app, go to Settings → Connectors and click Connect next to PostAxis again.
• Some posts were rejected during validation. The errors name the rule (caption length, image count, video format). Ask Cowork to fix only those posts and validate again.
• Posts landed at the wrong time. Put the timezone in the task and ask Cowork to move the affected posts with update_post.
• You want to stop Cowork from posting. Revoke Claude under Settings → API keys → Connected agents in PostAxis. Access ends immediately.

FAQ

Can Claude Cowork schedule 30 days of posts at once?

Yes. Cowork can send up to 50 posts in one bulk call. Ask it to validate first: PostAxis checks every post and saves nothing, so you can review the plan before it is scheduled. The overall limit is 300 posts per 24 hours per account through MCP.

Is Claude Cowork different from the Claude connector?

It uses the same PostAxis connector. Cowork is the mode where Claude works through longer tasks with your files, so it can prepare and schedule many posts in one go. For quick, conversational posts, regular Claude chats are usually faster.

Can Claude Cowork post images and videos?

Yes, media you already have. Cowork can pass PostAxis a public link to an image or video, or ask PostAxis for a one-time upload link for a file on your computer. PostAxis checks size, format and count for each network. It does not generate images or video.

Does Cowork post without asking me?

Cowork shows its plan and asks before creating posts. Combine that with validation and drafts, and nothing reaches your accounts without you seeing it. Everything it schedules also appears in the PostAxis calendar, where you can edit or delete it.

Do I need an API key?

No. Cowork signs in to PostAxis with OAuth through your Claude connector, which is included in every PostAxis plan.

Cowork is one of several agents that can run long social media tasks; Manus is another option, and if your content starts in a code repository, Claude Code may fit better. The complete guide to AI agents for social media compares all of them. See the Claude Cowork agent page for the short setup and the MCP reference for every tool. Start your 7-day free trial, connect your accounts and give Cowork its first folder.