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slick file

Upload a file to Slack. Probationary: the command is implemented and covered by mock tests, but it's hidden from slick --help and shell completion. Agent schema and workflow guidance mention it as probationary and not promoted until live-Slack smoke evidence completes.

slick file upload  Upload a file to Slack

file upload

slick file upload --channel C1234567890 --file ./report.txt

# Stream from stdin with explicit filename + title
tar czf - ./dist |
  slick file upload \
    --channel C1234567890 \
    --file - \
    --filename dist.tgz \
    --title "Build artifact"

# Reply in thread with the upload
slick file upload --channel C1234567890 --file ./report.txt --thread 1746284582.123456

# Preview without uploading
slick file upload --channel C1234567890 --file ./report.txt --dry-run

Flags

-c, --channel <CHANNEL>  Channel ID, name, or alias
-f, --file <FILE>        Path to upload or - for stdin
-N, --filename <NAME>    Filename for stdin or override
-T, --title <TITLE>      Slack file title
-m, --message <TEXT>     Initial comment
-b, --blocks             Treat upload message as raw Block Kit JSON
-t, --thread <TS>        Thread timestamp
-n, --dry-run            Preview without uploading
    --attribution                Force attribution on for this command
    --no-attribution             Disable attribution for this command
    --attribution-label <LABEL>      Override attribution label
    --attribution-emoji <EMOJI>      Override attribution emoji
    --attribution-message <TEXT>     Override attribution message

Progress and diagnostics go to stderr; stdout stays reserved for command data.

Output

Human (real upload — post-v0.4.0 the JSON fields now match Slack's own file object shape: file_id → id, file_name → name, size_human dropped in favour of human-mode-only formatting of the numeric size):

File uploaded channel=C7N2Q8L4P id=F0B2RSKLSJH name=slick-test.txt attribution=false size="48 B"

Human (--dry-run). id is the literal "dry-run" and the event carries dry_run=true; no Slack call is made:

File uploaded channel=C7N2Q8L4P id=dry-run name=report.txt attribution=false dry_run=true size="13 B"

JSON envelope (real upload):

{
  "data": {
    "file": {"id": "F0B2RSKLSJH", "name": "slick-test.txt", "size": 48},
    "channel": "C7N2Q8L4P",
    "attribution": false
  }
}

JSON envelope (--dry-run). file.id is the literal "dry-run" and the data record carries dry_run: true; no Slack call is made:

{
  "data": {
    "file": {"id": "dry-run", "name": "report.txt", "size": 13},
    "channel": "C7N2Q8L4P",
    "attribution": false,
    "dry_run": true
  }
}

Slack's files.completeUploadExternal does not populate permalink in the upload response; slick attempts to resolve it with files.info after upload. If that lookup fails, permalink stays absent.

Common errors

Error Cause Fix
not_in_channel (not_found, exit 2) App/user is not a member of the channel. Add the bot, or use a user-token profile.
validation_error: --file is required Missing --file. Provide the path or - for stdin.
validation_error: --filename required for stdin Stdin upload with no filename. Pass --filename.
missing_scope (auth_failure, exit 1) Token lacks files:write. Use the files or full manifest preset.

See also