Slack Channel Extension

Bidirectional Slack messaging for AgentOS via @slack/bolt.

What It Provides

• slackChannelSendMessage
• slackChannelSendMedia
• slackChannel

Runtime Status

• This is a curated channel pack.
• Channels stay opt-in because they can connect, poll, or receive webhooks.
• Enable it through createCuratedManifest({ channels: ['slack'] }) or a custom extension manifest.

Required Secrets

• slack.botToken
• slack.signingSecret
• slack.appToken

Posting to a person's own Slack link (./outbound)

A host that only posts messages, such as notes a person chose to send to a channel, takes the ./outbound entry. It loads no Bolt app, opens no port and needs none of the secrets above: the person makes the link in their own Slack workspace and the host keeps it as the secret it is.

import { parseSlackLink, postToSlackLink } from '@framers/agentos-ext-channel-slack/outbound';

const link = parseSlackLink(pasted); // null for anything that is not a Slack link
if (link === null) throw new Error('not a Slack incoming webhook or workflow link');

const outcome = await postToSlackLink(link, 'Decisions: ship on Friday.');
if (!outcome.ok && outcome.reason === 'link_gone') {
  // The link was removed, its channel archived or its workspace closed: ask the person for a new link.
}

parseSlackLink takes two kinds of link, and nothing else:

• an incoming webhook of an app in the person's workspace, https://hooks.slack.com/services/<workspace>/<B...>/<secret> (Slack's guide);
• a workflow's webhook trigger, https://hooks.slack.com/triggers/<workspace>/<number>/<secret>, made in Workflow Builder on Slack's paid plans (Slack's help). The workflow needs one text variable named text, which its message step shows.

Any other scheme, host, port (the default one written out included), user name, query, fragment, backslash or path is refused, and the link it returns is rebuilt on hooks.slack.com from the checked path, with its kind, its workspace id and its last four characters (ending) for a person to tell their links apart.

postToSlackLink(link, text, { fetch, timeoutMs, signal }) posts { "text": ... } as JSON, with the text escaped (&, < and > as &, < and >) for either kind of link. Slack reads an incoming webhook's text as its message formatting (Slack's formatting guide), and a workflow started by a webhook takes the same formatting in its variables (Slack's platform blog), so an unescaped <!channel>, <!here>, <@U...> or <#C...> would notify people or show a link the writer never wrote. escapeSlackText is the same escaping on its own. The post follows no redirect, gives up after 10 seconds unless timeoutMs says otherwise, and refuses text with nothing but spaces or with more than SLACK_TEXT_LIMIT (40,000) characters as the link gets it, the length above which Slack truncates a message (chat.postMessage). slackTextLength(kind, text) is that length, the escaped text's, for a host to show or check before a post.

It resolves with { ok: true }, or { ok: false, reason, retryAfterSeconds?, slackError? }:

slackError is Slack's error code when the answer carried one; nothing else from Slack's answer is returned. A 2xx answer is a post Slack took unless it is a JSON object whose top-level ok is false, so a post is never reported as failed and sent twice. Slack's answer is read from its body stream, to 8,192 characters at most, and the stream is then let go. An answer a fetch gives with no body stream is read by its status alone: its text() is never called, since that holds the whole answer at once however long it is. The timeout and the signal end the post themselves, so a fetch that leaves an answer's body pending still answers unavailable on time.

Source of Truth

• manifest.json defines the exported tools and messaging-channel descriptor.
• src/ contains the adapter and tool implementations.

Releases

New versions are published from framerslab/agentos-extensions by GitHub Actions through npm trusted publishing, with a provenance statement.