OpenCaw won't send files to a slack request

[nocturne reef]

I have integrated slack into the openclaw channels, gave all the needed scopes including file:write. I have a skill that generates reports successfully, but then is not being able to send the slack message with the file attached.

[swift shale]

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[steady holly]

A few common gotchas with Slack file sending in OpenClaw — if you answer the questions below we can narrow it down fast.

0) First: what’s the exact error + version?

1. openclaw --version
2. Paste the gateway log line / stack trace you get when it tries to send the attachment (even 10–20 lines is fine).

Without the error text we’re guessing between 3–4 different failure modes.

1) Scope name + reinstall (super common)

Slack’s scope is files:write (plural). I’ve seen people accidentally use/remember it as file:write.

Also: after changing scopes you must reinstall the Slack app to the workspace, otherwise your xoxb-... token won’t actually have the new scopes.

Docs (scope checklist): https://docs.openclaw.ai/channels/slack

2) Bot must be in the channel you’re sending to

Even with chat:write / files:write, Slack will return errors like not_in_channel if the bot/app isn’t invited to that channel (especially private channels).

3) Make sure you’re sending media the “OpenClaw way”

Outbound attachments from an agent reply require a standalone line like:

MEDIA:/path/to/report.pdf

(or use the CLI/tooling equivalent --media ...).

FAQ section: https://docs.openclaw.ai/help/faq#my-skill-generated-an-imagepdf-but-nothing-was-sent

4) Local file path must be inside allowed “media roots”

OpenClaw restricts what local paths it will read for outbound uploads. If your report is written somewhere random (e.g. ~/reports/...), the upload can fail even though the file exists.

Best fix: write the report into the agent workspace or OpenClaw state/tmp area (instead of an arbitrary folder), then attach that path.

5) Size limits (PDFs bite here)

Slack uploads go through OpenClaw’s media caps too. If your report is large, set:

• channels.slack.mediaMaxMb: <number>

Docs mention this under Slack media behavior: https://docs.openclaw.ai/channels/slack

Quick isolation test (recommended)

Try a direct CLI send (this bypasses your skill logic):

openclaw message send --channel slack --target channel:C12345678 \
  --message "test upload" --media /path/to/report.pdf

• If this fails, it’s Slack token/scopes/channel membership/size/path.
• If this works, the issue is how the skill constructs the reply (missing MEDIA: line, wrong path, etc.).

Send the error text + where the file is written (full path + size), and I’ll tell you which of the above it is.

[nocturne reef]

Maybe the point 4 is the issue. I have a skill for generating reports, it creates and stores them but they are not being uploaded i think because it can't access the files where it stored them. How i can check and fix this out ?

[steady holly]

Yep, that very often is the issue.

OpenClaw will not upload arbitrary local paths for security reasons. When sending MEDIA:... (or --media ...) it only allows files under a small set of “safe roots” (agent workspace, OpenClaw state dirs, OpenClaw temp dir, sandbox dirs). If your report generator writes to something like /tmp/report.pdf or ~/Downloads/..., Slack upload will fail.

Also quick correction: Slack’s scope is files:write (plural), not file:write — and you need to reinstall the Slack app after changing scopes.

How to check what’s failing (2 quick ways)

A) Easiest: reproduce with the CLI (you’ll get the real error)

On the machine where the Gateway runs:

openclaw message send --channel slack --target channel:YOUR_CHANNEL_ID \
  --message "test upload" --media /absolute/path/to/your/report.pdf

If the path is blocked you’ll see something like:

• LocalMediaAccessError: path-not-allowed
  or if it’s the wrong machine/path:
• Local media file not found

B) Check the gateway log for the exact error

Default log location:

tail -n 200 "${OPENCLAW_STATE_DIR:-$HOME/.openclaw}/logs/gateway.log" | rg -i "slack|upload|media|LocalMediaAccessError|path-not-allowed|not found"

What paths are “safe” to write to?

Best fix: write the report into the agent workspace.

Find your workspace:

openclaw config get agents.defaults.workspace

Default is usually: ~/.openclaw/workspace

Then change your skill/report script to write to e.g.:

• ~/.openclaw/workspace/reports/report.pdf

…and in the agent reply, attach it as either:

MEDIA:reports/report.pdf

(or absolute path, if you prefer)