UXC

One CLI for tools across protocols.

Slack Web API Skill

Use this skill to run Slack Web API operations through uxc + OpenAPI.

Reuse the uxc skill for shared execution, auth, and error-handling guidance.

Prerequisites

Scope

This skill covers a Messaging Core surface:

This skill does not cover:

Subscribe / Socket Mode Status

Slack inbound events can be delivered through Socket Mode. uxc now has a built-in Slack Socket Mode transport, but this skill still treats it as a limited event-ingest path rather than a fully packaged workflow surface.

Current uxc subscribe status:

What the current built-in transport already handles:

What is still not packaged:

Slack Socket Mode is now a validated IM subscribe provider at the transport/runtime level.

Authentication

Slack Web API uses Authorization: Bearer <token>.

Token types used in practice:

To create an app-level xapp-... token for Socket Mode:

  1. Open the target Slack app at https://api.slack.com/apps
  2. Go to Basic Information
  3. Find App-Level Tokens
  4. Generate a token with the connections:write scope
  5. Enable Socket Mode in the app configuration before relying on subscribe-based event intake

Option 1: Bot Token (Recommended Default)

Use the Slack Bot User OAuth Token (xoxb-...) for the default binding and for most messaging operations:

uxc auth credential set slack-bot \
  --auth-type bearer \
  --secret-env SLACK_BOT_TOKEN

uxc auth binding add \
  --id slack-bot \
  --host slack.com \
  --path-prefix /api \
  --scheme https \
  --credential slack-bot \
  --priority 100

Option 2: User Token (Explicit Override For Selected Reads)

Use a separate Slack User OAuth Token (xoxp-...) when the method requires user-token semantics, especially thread/history access outside bot-accessible conversations:

uxc auth credential set slack-user \
  --auth-type bearer \
  --secret-env SLACK_USER_TOKEN

Do not bind slack-user by default to the same host/path. Invoke it explicitly when needed:

uxc auth binding match https://slack.com/api
slack-openapi-cli --auth slack-user get:/conversations.replies channel=C1234567890 ts=1717171717.000100

If you intentionally want writes to appear as the installing user rather than the bot, you can also invoke write methods with --auth slack-user, but treat that as an explicit override rather than the default path.

Core Workflow

  1. Use the fixed link command by default:

    • command -v slack-openapi-cli
    • If missing, create it: uxc link slack-openapi-cli https://slack.com/api --schema-url https://raw.githubusercontent.com/holon-run/uxc/main/skills/slack-openapi-skill/references/slack-web.openapi.json
    • slack-openapi-cli -h

  2. Inspect operation schema first:

    • slack-openapi-cli get:/auth.test -h
    • slack-openapi-cli get:/conversations.history -h
    • slack-openapi-cli post:/chat.postMessage -h

  3. Prefer read validation before writes:

    • slack-openapi-cli get:/auth.test
    • slack-openapi-cli get:/conversations.list limit=20 types=public_channel,private_channel
    • slack-openapi-cli get:/conversations.info channel=C1234567890

  4. Execute with key/value or positional JSON:

    • key/value: slack-openapi-cli get:/conversations.history channel=C1234567890 limit=20
    • positional JSON: slack-openapi-cli post:/chat.postMessage '{"channel":"C1234567890","text":"Hello from UXC"}'

Operation Groups

Read / Lookup

Messaging / Reactions

Guardrails

References