Slack Step Reference

This page is generated from the public step inventory and shows the documented workflow contract for each public step.

Validation and Discovery

validate_connection

Validate the configured Slack connection and expose identity metadata.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: validate_connection

Used by built-in workflows: post-file, post-message, summarize-slack-target

Available to later steps: slack_auth, slack_team_id, slack_team_name, slack_user_id, slack_user_name

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
None documented.	-	-

Outputs (saved to ctx.data)

Name	Type	Description
slack_auth	UISlackAuth	Slack auth identity details from auth_test().
slack_team_id	str | None	Team identifier reported by Slack.
slack_team_name	str | None	Team name reported by Slack.
slack_user_id	str | None	User identifier reported by Slack.
slack_user_name	str | None	User name reported by Slack.

Returns

Result	Saved for later steps	Description
Success	slack_auth, slack_team_id, slack_team_name, slack_user_id, slack_user_name	If the Slack connection validates successfully.
Error	-	If the Slack client is not available or the auth request fails.

list_public_channels

List public Slack channels visible to the current token.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: list_public_channels

Available to later steps: slack_channels, slack_channels_next_cursor

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_limit	int, optional	Maximum number of channels to request. Defaults to 100.
slack_cursor	str, optional	Pagination cursor for the next page.
slack_exclude_archived	bool, optional	Whether to exclude archived channels. Defaults to True.

Outputs (saved to ctx.data)

Name	Type	Description
slack_channels	list[UISlackChannel]	Public channels returned by Slack.
slack_channels_next_cursor	str | None	Pagination cursor for a later request.

Returns

Result	Saved for later steps	Description
Success	slack_channels, slack_channels_next_cursor	If the channel list is retrieved successfully.
Error	-	If the Slack client is not available or the Slack request fails.

list_users

List Slack users visible to the current token.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: list_users

Available to later steps: slack_users, slack_users_next_cursor

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_limit	int, optional	Maximum number of users to request. Defaults to 100.
slack_cursor	str, optional	Pagination cursor for the next page.

Outputs (saved to ctx.data)

Name	Type	Description
slack_users	list[UISlackUser]	Users returned by Slack.
slack_users_next_cursor	str | None	Pagination cursor for a later request.

Returns

Result	Saved for later steps	Description
Success	slack_users, slack_users_next_cursor	If the user list is retrieved successfully.
Error	-	If the Slack client is not available or the Slack request fails.

Selection and Target Resolution

select_user_target

Select a Slack user target through query filtering and final confirmation.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: select_user_target

Available to later steps: slack_target, slack_target_type, slack_target_id, slack_target_name, slack_target_query

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_target_query	str, optional	Pre-filled query used to filter Slack users.
slack_search_limit	int, optional	Maximum number of matches to return. Defaults to 20.
slack_search_page_size	int, optional	Page size used while scanning Slack users. Defaults to 1000.
slack_search_max_pages	int, optional	Maximum pages to scan while searching. Defaults to 50.

Outputs (saved to ctx.data)

Name	Type	Description
slack_target	UISlackTarget	Canonical selected Slack target.
slack_target_type	str	Selected target type (user).
slack_target_id	str	Slack user ID.
slack_target_name	str	User-facing target name.
slack_target_query	str	Query used to resolve the selection.

Returns

Result	Saved for later steps	Description
Success	slack_target, slack_target_type, slack_target_id, slack_target_name, slack_target_query	If the user target is selected successfully.
Error	-	If Slack is unavailable, the query is invalid, the search fails, or no match is selected.

select_channel_target

Select a Slack channel target through query filtering and final confirmation.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: select_channel_target

Available to later steps: slack_target, slack_target_type, slack_target_id, slack_target_name, slack_target_query

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_target_query	str, optional	Pre-filled query used to filter Slack channels.
slack_search_limit	int, optional	Maximum number of matches to return. Defaults to 20.
slack_search_page_size	int, optional	Page size used while scanning Slack channels. Defaults to 1000.
slack_search_max_pages	int, optional	Maximum pages to scan while searching. Defaults to 50.
slack_exclude_archived	bool, optional	Whether to exclude archived channels while searching. Defaults to True.

Outputs (saved to ctx.data)

Name	Type	Description
slack_target	UISlackTarget	Canonical selected Slack target.
slack_target_type	str	Selected target type (channel).
slack_target_id	str	Slack channel ID.
slack_target_name	str	User-facing target name.
slack_target_query	str	Query used to resolve the selection.

Returns

Result	Saved for later steps	Description
Success	slack_target, slack_target_type, slack_target_id, slack_target_name, slack_target_query	If the channel target is selected successfully.
Error	-	If Slack is unavailable, the query is invalid, the search fails, or no match is selected.

select_default_or_search_channel_target

Select Slack targets from a preferred value, configured defaults, or search.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: select_default_or_search_channel_target

Used by built-in workflows: post-file, post-message

Available to later steps: slack_target, target was resolved viaslack_preferred_targetor manual search., slack_targets, that resolved successfully, when one or more configured default channels were, selected via the checklist., slack_conversation_ids, that resolved successfully, set together withslack_targets., slack_unresolved_channels, be resolved, set together withslack_targets. Empty when every checked channel, resolved.

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_preferred_target	str, optional	Person or channel name (without #) to select
automatically without prompting, when it resolves to exactly one match. Takes priority	-	-
over configured default channels and manual search.	-	-
slack_target_query	str, optional	Pre-filled query used if the user falls back to search.
slack_search_limit	int, optional	Maximum number of matches to return during manual search. Defaults to 20.
slack_search_page_size	int, optional	Page size used while scanning Slack. Defaults to 1000.
slack_search_max_pages	int, optional	Maximum pages to scan while searching. Defaults to 50.
slack_exclude_archived	bool, optional	Whether to exclude archived channels while searching. Defaults to True.

Outputs (saved to ctx.data)

Name	Type	Description
slack_target	UISlackTarget, optional	Canonical selected Slack target, when exactly one
target was resolved via slack_preferred_target or manual search.	-	-
slack_targets	list[UISlackTarget], optional	Resolved targets for every checked channel
that resolved successfully, when one or more configured default channels were	-	-
selected via the checklist.	-	-
slack_conversation_ids	list[str], optional	Conversation IDs for every checked channel
that resolved successfully, set together with slack_targets.	-	-
slack_unresolved_channels	list[str], optional	Names of checked channels that could not
be resolved, set together with slack_targets. Empty when every checked channel	-	-
resolved.	-	-

Returns

Result	Saved for later steps	Description
Success	slack_target, target was resolved viaslack_preferred_targetor manual search., slack_targets, that resolved successfully, when one or more configured default channels were, selected via the checklist., slack_conversation_ids, that resolved successfully, set together withslack_targets., slack_unresolved_channels, be resolved, set together withslack_targets. Empty when every checked channel, resolved.	If at least one selected target was resolved (channels that failed to resolve
are skipped with a warning, the rest still get posted to).	-	-
Error	-	If Slack is unavailable, or none of the selected channels could be resolved.

Messaging

prepare_message_destination

Prepare a Slack message destination from the selected target(s).

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: prepare_message_destination

Used by built-in workflows: post-file, post-message

Available to later steps: slack_conversation, conversation, when a singleslack_targetwas used., slack_conversation_id, operations, when a singleslack_targetwas used., slack_conversation_name, together withslack_conversation_id., slack_conversation_ids, slack_targets`, when multiple targets were used.`, `slack_conversation_names`,slack_conversation_ids, set together withslack_conversation_ids.

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_targets	list[UISlackTarget], optional	Selected Slack channel targets, when
multiple channels were checked via a checklist (e.g.	-	-
select_default_or_search_channel_target). Takes priority over slack_target.	-	-
slack_target	UISlackTarget, optional	Selected Slack target. Must be a user or
channel target. Used when slack_targets is not set.	-	-

Outputs (saved to ctx.data)

Name	Type	Description
slack_conversation	UISlackConversation, optional	Resolved Slack destination
conversation, when a single slack_target was used.	-	-
slack_conversation_id	str, optional	Conversation or channel ID used for later message
operations, when a single slack_target was used.	-	-
slack_conversation_name	str, optional	User-facing name of the destination, set
together with slack_conversation_id.	-	-
slack_conversation_ids	list[str], optional	Conversation IDs for every channel in
slack_targets, when multiple targets were used.	-	-
slack_conversation_names	list[str], optional	User-facing names for every channel in
slack_conversation_ids, set together with slack_conversation_ids.	-	-

Returns

Result	Saved for later steps	Description
Success	slack_conversation, conversation, when a singleslack_targetwas used., slack_conversation_id, operations, when a singleslack_targetwas used., slack_conversation_name, together withslack_conversation_id., slack_conversation_ids, slack_targets`, when multiple targets were used.`, `slack_conversation_names`,slack_conversation_ids, set together withslack_conversation_ids.	If the Slack message destination(s) are ready.
Error	-	If Slack is unavailable, no target is provided, or the Slack request fails.

open_direct_message

Open or reuse a direct message conversation for the selected Slack user target.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: open_direct_message

Available to later steps: slack_conversation, slack_conversation_id

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_target	UISlackTarget	Selected Slack target. Must be a user target.

Outputs (saved to ctx.data)

Name	Type	Description
slack_conversation	UISlackConversation	Opened or reused Slack conversation.
slack_conversation_id	str	Conversation ID used for later message operations.

Returns

Result	Saved for later steps	Description
Success	slack_conversation, slack_conversation_id	If the direct message conversation is ready.
Error	-	If Slack is unavailable, the target is missing or invalid, or the Slack request fails.

prompt_message_body

Capture a multiline Slack message for later formatting and posting.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: prompt_message_body

Used by built-in workflows: post-message

Available to later steps: slack_message_markdown

Inputs (from ctx.data)

Name	Type	Description
slack_message_text	str, optional	Already Slack-ready message text. If present, the prompt is skipped.
slack_message_markdown	str, optional	Standard Markdown message already provided by a caller. If
present (and slack_message_text isn't), the prompt is skipped.	-	-

Outputs (saved to ctx.data)

Name	Type	Description
slack_message_markdown	str	Captured message text, to be converted to Slack mrkdwn by a later step.

Returns

Result	Saved for later steps	Description
Success	slack_message_markdown	If the message body is captured successfully.
Skip	slack_message_markdown	If a message was already provided by the caller.
Error	-	If the user cancels or the message body is empty.

format_markdown_message

Convert a standard Markdown message into Slack mrkdwn, if provided.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: format_markdown_message

Used by built-in workflows: post-file, post-message

Available to later steps: slack_message_text

Inputs (from ctx.data)

Name	Type	Description
slack_message_text	str, optional	Already Slack-ready text. If present, this step does
nothing and leaves it untouched.	-	-
slack_message_markdown	str, optional	Standard Markdown text to convert to Slack mrkdwn.
Ignored when slack_message_text is already present.	-	-

Outputs (saved to ctx.data)

Name	Type	Description
slack_message_text	str	Slack mrkdwn-ready message text, when slack_message_markdown was converted.

Returns

Result	Saved for later steps	Description
Skip	slack_message_text	If slack_message_text is already set, or neither input is provided (a later step
can still prompt the user to compose one interactively).	-	-
Success	slack_message_text	If slack_message_markdown was converted successfully.
Error	-	If the Textual UI context is not available.

post_message

Post a plain-text Slack message to the prepared conversation(s).

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: post_message

Used by built-in workflows: post-message

Available to later steps: slack_message, single conversation was used., slack_message_ts, conversation was used., slack_message_channel, conversation was used., slack_messages, conversation that succeeded, when multiple conversations were used., slack_message_channels, posted to, when multiple conversations were used.

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_conversation_ids	list[str], optional	Slack conversation IDs to post into. Takes
priority over slack_conversation_id when set.	-	-
slack_conversation_id	str, optional	Single Slack conversation ID to post into. Used
when slack_conversation_ids is not set.	-	-
slack_message_text	str	Message body to post.
slack_thread_ts	str, optional	Thread timestamp for replies. Only applied when posting
to a single conversation.	-	-

Outputs (saved to ctx.data)

Name	Type	Description
slack_message	UISlackPostedMessage, optional	Posted Slack message metadata, when a
single conversation was used.	-	-
slack_message_ts	str, optional	Timestamp of the posted message, when a single
conversation was used.	-	-
slack_message_channel	str, optional	Channel the message was posted to, when a single
conversation was used.	-	-
slack_messages	list[UISlackPostedMessage], optional	Posted message metadata for every
conversation that succeeded, when multiple conversations were used.	-	-
slack_message_channels	list[str], optional	Channels the message was successfully
posted to, when multiple conversations were used.	-	-

Returns

Result	Saved for later steps	Description
Success	slack_message, single conversation was used., slack_message_ts, conversation was used., slack_message_channel, conversation was used., slack_messages, conversation that succeeded, when multiple conversations were used., slack_message_channels, posted to, when multiple conversations were used.	If the Slack message is posted to at least one conversation.
Error	-	If Slack is unavailable, required context is missing, or every post fails.

upload_file

Upload a local file to the prepared Slack conversation(s), with an optional message above it.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: upload_file

Used by built-in workflows: post-file

Available to later steps: slack_uploaded_file, slack_uploaded_files

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient with the files:write scope.

Inputs (from ctx.data)

Name	Type	Description
slack_file_path	str	Local path of the file to upload.
slack_file_title	str, optional	Title shown on the Slack file. Defaults to the file name.
slack_message_text	str, optional	Slack-ready text posted as the message above the file.
slack_conversation_ids	list[str], optional	Conversation IDs to upload into; wins over slack_conversation_id.
slack_conversation_id	str, optional	Single conversation ID, used when slack_conversation_ids is not set.
slack_thread_ts	str, optional	Thread timestamp to share the file into; single conversation only.

Outputs (saved to ctx.data)

Name	Type	Description
slack_uploaded_file	UISlackUploadedFile, optional	Uploaded file metadata, single conversation case.
slack_uploaded_files	list[UISlackUploadedFile], optional	Uploaded file metadata per successful conversation.

Returns

Result	Saved for later steps	Description
Success	slack_uploaded_file, slack_uploaded_files	If the file is uploaded to at least one conversation.
Error	-	If Slack is unavailable, the file is missing, or every upload fails.

Conversation Summaries

select_target

Search both Slack users and channels for a single unified target selection.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: select_target

Used by built-in workflows: summarize-slack-target

Available to later steps: slack_target, slack_target_type, slack_target_id, slack_target_name, slack_target_query

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_target_query	str, optional	Query used to search both users and channels.
slack_search_limit	int, optional	Maximum number of matches to keep from each search. Defaults to 10.
slack_search_page_size	int, optional	Page size used while scanning Slack. Defaults to 1000.
slack_search_max_pages	int, optional	Maximum pages to scan while searching. Defaults to 50.
slack_exclude_archived	bool, optional	Whether to exclude archived channels. Defaults to True.

Outputs (saved to ctx.data)

Name	Type	Description
slack_target	UISlackTarget	Canonical selected Slack target.
slack_target_type	str	Selected target type (user or channel).
slack_target_id	str	Slack target identifier.
slack_target_name	str	User-facing target name.
slack_target_query	str	Query used to resolve the selection.

Returns

Result	Saved for later steps	Description
Success	slack_target, slack_target_type, slack_target_id, slack_target_name, slack_target_query	If the unified target is selected successfully.
Error	-	If Slack is unavailable, the query is invalid, the search fails, or no match is selected.

ensure_target_conversation

Resolve a Slack conversation from the selected target.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: ensure_target_conversation

Used by built-in workflows: summarize-slack-target

Available to later steps: slack_conversation, slack_conversation_id

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_target	UISlackTarget	Selected Slack target.

Outputs (saved to ctx.data)

Name	Type	Description
slack_conversation	UISlackConversation	Resolved Slack conversation.
slack_conversation_id	str	Conversation ID used for later operations.

Returns

Result	Saved for later steps	Description
Success	slack_conversation, slack_conversation_id	If the target conversation is resolved successfully.
Error	-	If Slack is unavailable, the target is missing, or the Slack request fails.

read_recent_messages

Read the most recent messages from the resolved Slack conversation.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: read_recent_messages

Used by built-in workflows: summarize-slack-target

Available to later steps: slack_messages, slack_user_display_names, slack_channel_display_names, slack_messages_next_cursor, slack_messages_has_more

Requires

Name	Type	Description
ctx.slack	-	An initialized SlackClient.

Inputs (from ctx.data)

Name	Type	Description
slack_conversation_id	str	Slack conversation ID to read.
slack_history_limit	int, optional	Number of recent messages to fetch. Defaults to 30.

Outputs (saved to ctx.data)

Name	Type	Description
slack_messages	list[UISlackMessage]	Retrieved Slack messages.
slack_user_display_names	dict[str, str]	Resolved Slack user display names keyed by user ID.
slack_channel_display_names	dict[str, str]	Resolved Slack channel names keyed by channel ID.
slack_messages_next_cursor	str | None	Pagination cursor for later reads.
slack_messages_has_more	bool	Whether more messages are available.

Returns

Result	Saved for later steps	Description
Success	slack_messages, slack_user_display_names, slack_channel_display_names, slack_messages_next_cursor, slack_messages_has_more	If recent messages are retrieved successfully.
Error	-	If Slack is unavailable, required context is missing, or the Slack request fails.

ai_summarize_messages

Summarize recent Slack messages with AI.

How to read this contract

• Inputs (from ctx.data) shows what the step expects before it runs.
• Outputs (saved to ctx.data) shows the metadata keys later steps can read after Success or Skip.
• Returns describes the workflow result type (Success, Skip, Error, Exit), not a separate function return payload.

Workflow usage

- plugin: slack
  step: ai_summarize_messages

Used by built-in workflows: summarize-slack-target

Available to later steps: slack_summary, slack_summary_source_count, slack_summary_transcript_chars

Requires

Name	Type	Description
ctx.textual	-	Textual UI context.

Inputs (from ctx.data)

Name	Type	Description
slack_messages	list[UISlackMessage]	Messages to summarize.
slack_target_name	str, optional	Human-facing target label for the summary.
slack_summary_max_chars	int, optional	Maximum transcript size passed to AI. Defaults to 12000.

Outputs (saved to ctx.data)

Name	Type	Description
slack_summary	str	AI-generated Slack summary.
slack_summary_source_count	int	Number of source messages summarized.
slack_summary_transcript_chars	int	Transcript size sent to AI after truncation.

Returns

Result	Saved for later steps	Description
Success	slack_summary, slack_summary_source_count, slack_summary_transcript_chars	If the summary is generated successfully.
Skip	slack_summary, slack_summary_source_count, slack_summary_transcript_chars	If AI is not configured or not available.
Error	-	If messages are missing or the AI request fails.