Call the Slack Web API to post messages, list channels, read history, and look up users.

Provided free and as is, without warranty of any kind — including merchantability, fitness for a particular purpose, and the accuracy or completeness of any result. See the licence. You are responsible for checking what this produces before relying on it.

Slack

Call the Slack Web API to post messages and read workspace data. Pure Python standard library, no external dependencies.

What it does

Branches on an operation and makes one authenticated call to https://slack.com/api/<method>. The token is sent in the Authorization: Bearer <token> header (Slack's preferred scheme); write operations POST as application/x-www-form-urlencoded.

Slack always responds 200 OK with a JSON body carrying a top-level ok boolean. On ok:false the tool returns Slack's error string in status (e.g. not_in_channel, channel_not_found, invalid_auth) rather than crashing, so the assistant can react.

Operations

operation	reads/writes	required input	returns in `result`
`chat.postMessage`	write	`channel`, `text`	`{ts, channel}` of the posted message
`conversations.list`	read	—	array of channels (`id`, `name`, ...)
`conversations.history`	read	`channel`	array of recent messages
`users.info`	read	`user`	the user object (profile, name, ...)

limit (default 100, max 1000) caps conversations.list / conversations.history. When Slack paginates, the cursor is returned as nextCursor.

Outputs

result — the useful payload as a JSON string
status — ok on success, otherwise Slack's error code
ok — "true" / "false"
operation — echo of the operation
nextCursor — present only when more pages are available

Credential

This tool is credential-based. The token is not a task input — it lives in the vault and is bound to the task by name, so it never appears in a workflow definition, an export, or a log.

Create a Slack app at https://api.slack.com/apps → From scratch.
Under OAuth & Permissions, add Bot Token Scopes: chat:write, channels:read, channels:history, users:read.
Install to Workspace and copy the Bot User OAuth Token (starts with xoxb-). A user token (xoxp-) also works.
In InTouch, create a credential of type API Key and paste the token as the secret. Leave baseUrl empty — Slack's API host is fixed, and the token is what selects the workspace.
Put that credential's name in the task's credentialName field.
For posting/reading a private channel, invite the bot to it: /invite @YourApp.

Examples

Each assumes an API Key credential named Slack is attached to the task.

Post a message:

slack operation=chat.postMessage channel=C0123ABCD text="Build #42 passed ✅"

List the workspace's channels:

slack operation=conversations.list limit=200

Read the 50 most recent messages in a channel:

slack operation=conversations.history channel=C0123ABCD limit=50

Look up a user:

slack operation=users.info user=U0123ABCD

Publishes

The keys a later task may reference as {{taskName.key}}. Referencing anything not listed here resolves to nothing at run time.

error
nextCursor
ok
operation
result
status

Input Properties

Every property this tool accepts, from its own tool.iml.

Property	Type	Required	Default	Description
`operation`	string	yes	—	One of: chat.postMessage, conversations.list, conversations.history, users.info
`channel`	string	no	—	Channel ID (e.g. C0123ABCD) or #name. Required for chat.postMessage and conversations.history.
`text`	string	no	—	Message text. Required for chat.postMessage.
`user`	string	no	—	User ID (e.g. U0123ABCD). Required for users.info.
`limit`	string	no	`100`	Max items to return for conversations.list / conversations.history (1-1000).
`allowErrors`	string	no	—	Comma-separated Slack error codes to TOLERATE instead of failing the step (e.g. "not_in_channel,channel_not_found"), or "*" for all. Empty means any ok:false from Slack fails the task — which is what you want, because a workflow that reports success while doing nothing is worse than one that stops.
`types`	string	no	`public_channel`	Channel types for conversations.list: public_channel (default), private_channel, mpim, im — comma-separated. Anything beyond public_channel needs extra Slack scopes: private_channel requires groups:read, im requires im:read. Left alone, this asks for no more than a public-community digest needs.