Attachments

Slack, Discord, and Telegram can materialize inbound files into the active conversation workspace and upload generated files in replies.

Inbound files

Files are downloaded before Pi receives the message and stored under:

/workspace/attachments/{messageId}/...

Pi receives the managed runtime path rather than a temporary platform URL. A failed attachment batch removes partial files and fails the message before model execution.

Configure limits per adapter:

slack({
	token,
	appToken,
	attachments: {
		maxBytes: 20 * 1024 * 1024,
		timeoutMs: 30_000,
		mimeTypes: ["image/*", "application/pdf", "text/plain"],
		retry: { attempts: 3 },
	},
});

Built-in adapters restrict downloads to platform file hosts. Setting hosts replaces that allowlist, including redirect destinations. Keep the list narrow.

Outbound files

Pi sends generated files through chat_attach:

chat_attach({ paths: ["reports/summary.pdf"], text: "Report ready." })

Paths must remain under /workspace or /shared. Built-in chat adapters upload local files when their APIs support it; other adapters return path or link references in text.

Remote runtimes synchronize generated files back before attachment delivery. Custom runtimes must provide equivalent consistency if shell commands can create files outside the runtime file API.