docs: add slack plugin install steps for coding agents

README.md

@@ -49,6 +49,50 @@ $ slack create my-github-app -t slack-samples/deno-github-functions
 $ cd my-github-app
 ```
 
+### Claude Code, Codex, Cursor, and Other Coding Agents
+
+Install the
+[Slack MCP and Skills Plugin](https://docs.slack.dev/ai/slack-skills-plugin/) so
+your coding agent can create, run, and deploy Slack apps, look up Web API
+methods and scopes, and build Block Kit without guessing.
+
+#### Claude Code
+
+Run this in a Claude Code session:
+
+```
+/plugin install slack@claude-plugins-official
+```
+
+#### Codex
+
+Run this in your terminal:
+
+```sh
+codex plugin marketplace add slackapi/slack-skills-plugin
+codex plugin add slack@slack
+```
+
+#### Cursor
+
+Run this in a Cursor Agent chat:
+
+```
+/add-plugin slack
+```
+
+#### Other agents
+
+Install the skills with `npx skills`, using your
+[agent's identifier](https://github.com/vercel-labs/skills#supported-agents):
+
+```sh
+npx skills add slackapi/slack-skills-plugin -y -a <agent>
+
+# For example, OpenCode
+npx skills add slackapi/slack-skills-plugin -y -a opencode
+```
+
 ### Register a GitHub App
 
 With [external authentication](https://api.slack.com/automation/external-auth)