fast-io

name	fast-io
description	Cloud file management and collaboration platform. Complete agent guide with all 258 tools — parameters, workflows, ID formats, and constraints. Use this skill when the user needs to store files, create branded shares (Send/Receive/Exchange), or query documents using built-in RAG AI. Supports transferring ownership to humans, managing workspaces, and real-time collaboration. Provides a free agent plan with 50 GB storage and 5,000 monthly credits.
license	Proprietary
compatibility	Requires network access. Connects to the Fast.io MCP server at mcp.fast.io via Streamable HTTP (/mcp) or SSE (/sse).
metadata	{"author":"fast-io","version":"1.35.0"}
homepage	https://fast.io

Fast.io MCP Server -- AI Agent Guide

Version: 1.35 Last Updated: 2026-02-06

The complete guide for AI agents using the Fast.io MCP server. Covers why and how to use the platform: product capabilities, the free agent plan, authentication, core concepts (workspaces, shares, intelligence, previews, comments, URL import, real-time collaboration, ownership transfer), 10 end-to-end workflows, and all 258 tools organized by module.

Platform reference. For a comprehensive overview of Fast.io's capabilities, the agent plan, key workflows, and upgrade paths, see references/REFERENCE.md.

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1. Overview

Store files. Share with humans. Query with AI. All through one API -- free.

Fast.io is a cloud storage and collaboration platform that gives AI agents a complete file management, sharing, and intelligence layer. Upload outputs, create branded data rooms, ask questions about documents using built-in RAG, and hand everything off to a human when the job is done. No infrastructure to manage, no subscriptions to set up, no credit card required.

The Problem Fast.io Solves

AI agents generate files, reports, datasets, and deliverables -- but getting those outputs to humans is messy. You end up cobbling together S3 buckets, presigned URLs, email attachments, and custom download pages. Every agent reinvents file sharing, and none of it looks professional.

When agents need to understand documents -- not just store them -- they have to download files, parse dozens of formats, build search indexes, and manage their own RAG pipeline. That is a lot of infrastructure for what should be a simple question: "What does this document say?"

Problem	Fast.io Solution
Nowhere professional to put agent outputs	Branded workspaces and data rooms with file preview for 10+ formats
Sharing files with humans is awkward	Purpose-built shares (Send, Receive, Exchange) with link sharing, passwords, expiration
Collecting files from humans is harder	Receive shares let humans upload directly to you -- no email attachments
Understanding document contents	Built-in AI reads, summarizes, and answers questions about your files
Building a RAG pipeline from scratch	Enable intelligence on a workspace and files are automatically indexed, summarized, and queryable
Finding the right file in a large collection	Semantic search finds files by meaning, not just filename
Handing a project off to a human	One-click ownership transfer -- human gets the org, agent keeps admin access
Tracking what happened	Full audit trail with AI-powered activity summaries
Cost	Free. 50 GB storage, 5,000 monthly credits, no credit card

MCP Server

This MCP server exposes 267 tools that cover the full Fast.io REST API surface. Every authenticated API endpoint has a corresponding tool, and the server handles session management automatically.

Once a user authenticates, the auth token is stored in the server session and automatically attached to all subsequent API calls. There is no need to pass tokens between tool invocations.

Server Endpoints

• Production: mcp.fast.io
• Development: mcp.fastdev1.com

Two transports are available on each:

• Streamable HTTP at /mcp -- the preferred transport for new integrations.
• SSE at /sse -- a legacy transport maintained for backward compatibility.

MCP Resources

The server exposes two MCP resources that clients can read directly via resources/list and resources/read:

URI	Name	Description	MIME Type
skill://guide	skill-guide	Full agent guide (this document) with all 267 tools, workflows, and platform documentation	text/markdown
session://status	session-status	Current authentication state: authenticated boolean, user_id, user_email, token_expires_at (Unix epoch), token_expires_at_iso (ISO 8601)	application/json

MCP Prompts

The server provides 8 guided prompts for common operations via prompts/list and prompts/get:

Prompt	Description
get-started	Complete onboarding: create account, org, and workspace. Covers new agents, returning users, and invited agents.
create-share	Guide for creating shares. Explains Send/Receive/Exchange types, helps choose the right one, lists parameters.
ask-ai	Guide for AI chat. Explains scoping (folder/file scope vs attachments), intelligence requirements, polling.
upload-file	Choose the right upload method. Single-step upload-text-file vs chunked flow for binary/large files.
transfer-to-human	Transfer org ownership to a human. Explains the process, implications, and claim URL workflow.
discover-content	Find all accessible orgs/workspaces. Explains internal vs external orgs and why both tools are needed.
invite-collaborator	Invite people to orgs, workspaces, or shares. Explains permission levels and message requirements.
setup-branding	Customize branding. Explains asset hierarchy (org → workspace → share) and upload methods.

Additional References

• Agent guide: This document contains the complete tool documentation, workflows, and constraints.
• Platform reference: See references/REFERENCE.md for platform capabilities, agent plan details, and upgrade paths.

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2. Authentication (Critical First Step)

Authentication is required before calling any tool except these unauthenticated tools:

• system-status
• ping
• auth-signin
• auth-signup
• auth-set-api-key
• auth-email-check
• auth-password-reset-request
• auth-password-reset
• quickshare-details

Choosing the Right Approach

There are three ways to use Fast.io as an agent, depending on whether you are operating autonomously or assisting an existing human user.

Option 1: Autonomous Agent -- Create an Agent Account

If you are operating independently (storing files, running workflows, building workspaces for users), create your own agent account with auth-signup. Agent accounts get the free agent plan (50 GB, 5,000 monthly credits) and can transfer orgs to humans when ready. This is the recommended path for autonomous agents. See Agent Account Creation below for steps.

Option 2: Assisting a Human -- Use Their API Key

If a human already has a Fast.io account and wants your help managing their files, workspaces, or shares, they can create an API key for you to use. No separate agent account is needed -- you operate as the human user. The human creates a key at Settings -> Devices & Agents -> API Keys (direct link: https://go.fast.io/settings/api-keys). Call auth-set-api-key with the key to authenticate -- the key is validated and stored in the session automatically. API keys are a 1:1 replacement for JWT tokens: they work as Bearer tokens with the same permissions as the account owner and do not expire unless revoked. Agents can also manage API keys programmatically with auth-api-key-create, auth-api-key-list, and auth-api-key-delete.

Option 3: Agent Account Invited to a Human's Org

If you want your own agent identity but need to work within a human's existing organization, create an agent account with auth-signup, then have the human invite you to their org with org-invite-member or to a workspace with workspace-member-add. Alternatively the human can invite via the UI: Settings -> Your Organization -> Manage People. This gives you access to their workspaces and shares while keeping your own account separate. After accepting invitations with user-invitations-accept-all, use auth-signin to authenticate normally. Note: If the human only invites you to a workspace (not the org), the org will appear as external -- see Internal vs External Orgs in the Organizations section.

Scenario	Recommended Approach
Operating autonomously, storing files, building for users	Create an agent account with your own org (Option 1)
Helping a human manage their existing account	Ask the human to create an API key for you (Option 2)
Working within a human's org with your own identity	Create an agent account, have the human invite you (Option 3)
Building something to hand off to a human	Create an agent account, build it, then transfer the org (Option 1)

Credit limits by account type: Agent accounts (Options 1, 3) can transfer orgs to humans when credits run out -- see Ownership Transfer in section 3. Human accounts (Option 2) cannot use the transfer/claim API; direct the human to upgrade their plan at https://go.fast.io/settings/billing or via org-billing-create.

Standard Sign-In Flow

1. Call auth-signin with email and password.
2. The server returns a JWT auth_token and stores it in the session automatically.
3. All subsequent tool calls use this token without any manual passing.

Agent Account Creation

When creating a new account (Options 1 and 3 above), agents MUST use auth-signup which automatically registers with agent=true. Never sign up as a human account. Agent accounts provide:

• account_type set to "agent"
• Free agent plan assigned automatically
• Transfer/claim workflow enabled for handing orgs off to humans

Steps:

1. Optionally call auth-email-check with the desired email to verify it is available for registration before attempting signup.
2. Call auth-signup with first_name, last_name, email, and password. The agent=true flag is sent automatically by the MCP server.
3. The account is created and a session is established automatically -- the agent is signed in immediately.
4. Verify your email (required before using most endpoints): Call auth-email-verify with email to send a verification code, then call auth-email-verify again with email and email_token to validate the code.
5. No credit card is required. No trial period. No expiration. The account persists indefinitely.

Two-Factor Authentication Flow

1. Call auth-signin with email and password.
2. If the response includes two_factor_required: true, the returned token has limited scope.
3. Call auth-2fa-verify with the 2FA code (TOTP, SMS, or WhatsApp).
4. The server replaces the limited-scope token with a full-scope token automatically.

Checking Session Status

• auth-status -- checks the local Durable Object session. No API call is made. Returns authentication state, user ID, email, and token expiry.
• auth-check -- validates the token against the Fast.io API. Returns the user ID if the token is still valid.

Session Expiry

JWT tokens last 1 hour. API keys (used when assisting a human) do not expire unless revoked. When a JWT session expires, tool calls return a clear error indicating that re-authentication is needed. Call auth-signin again to establish a new session. The MCP server does not auto-refresh tokens.

Tip: For long-running sessions, use auth-status to check remaining token lifetime before starting a multi-step workflow. If the token is close to expiring, re-authenticate first to avoid mid-workflow interruptions.

Signing Out

Call auth-signout to clear the stored session from the Durable Object.

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3. Core Concepts

Organizations

Organizations are the top-level container in Fast.io. Every user belongs to one or more organizations. Organizations have:

• Members with roles: owner, admin, member, guest, view.
• Billing and subscriptions managed through Stripe integration.
• Workspaces that belong to the organization.
• Plan limits that govern storage, transfer, AI tokens, and member counts.

Organizations are identified by a 19-digit numeric profile ID or a domain string.

IMPORTANT: When creating orgs, agents MUST use org-create which automatically assigns billing_plan: "agent". This ensures the org gets the free agent plan (50 GB, 5,000 credits/month). Do not use any other billing plan for agent-created organizations.

Org Discovery (IMPORTANT)

To discover all available orgs, agents must call both endpoints:

1. list-orgs -- returns internal orgs where you are a direct member (member: true)
2. orgs-external -- returns external orgs you access via workspace membership only (member: false)

An agent that only checks list-orgs will miss external orgs entirely and won't discover the workspaces it's been invited to. External orgs are the most common pattern when a human invites an agent to help with a specific project -- they add the agent to a workspace but not to the org itself.

Internal vs External Orgs

Internal orgs (member: true) -- orgs you created or were invited to join as a member. You have org-level access: you can see all workspaces (subject to permissions), manage settings if you're an admin, and appear in the org's member list.

External orgs (member: false) -- orgs you can access only through workspace membership. You can see the org's name and basic public info, but you cannot manage org settings, see other workspaces, or add members at the org level. Your access is limited to the specific workspaces you were explicitly invited to.

Example: A human invites your agent to their "Q4 Reports" workspace. You can upload files, run AI queries, and collaborate in that workspace. But you cannot create new workspaces in their org, view their billing, or access their other workspaces. The org shows up via orgs-external -- not list-orgs. If the human later invites you to the org itself, the org moves from external to internal.

Workspaces

Workspaces are file storage containers within organizations. Each workspace has:

• Its own set of members with roles (owner, admin, member, guest).
• A storage tree of files and folders (storage nodes).
• Optional AI features for RAG-powered chat.
• Shares that can be created within the workspace.
• Archive/unarchive lifecycle management.
• 50 GB included storage on the free agent plan, with files up to 1 GB per upload.
• File versioning -- every edit creates a new version, old versions are recoverable.
• Full-text and semantic search -- find files by name, content, or meaning.

Workspaces are identified by a 19-digit numeric profile ID.

Intelligence: On or Off

Workspaces have an intelligence toggle that controls whether AI features are active:

Intelligence OFF -- the workspace is pure file storage. You can still attach files directly to an AI chat conversation (up to 10 files), but files are not persistently indexed. This is fine for simple storage and sharing where you do not need to query your content.

Intelligence ON -- the workspace becomes an AI-powered knowledge base. Every file uploaded is automatically ingested, summarized, and indexed. This enables:

• RAG (retrieval-augmented generation) -- scope AI chat to entire folders or the full workspace and ask questions across all your content. The AI retrieves relevant passages and answers with citations.
• Semantic search -- find files by meaning, not just keywords. "Show me contracts with indemnity clauses" works even if those exact words do not appear in the filename.
• Auto-summarization -- short and long summaries generated for every file, searchable and visible in the UI.
• Metadata extraction -- AI pulls key metadata from documents automatically.

Intelligence defaults to ON for workspaces created via the API by agent accounts. If you are just using Fast.io for storage and sharing, disable it to conserve credits. If you need to query your content, leave it enabled.

Agent use case: Create a workspace per project or client. Enable intelligence if you need to query the content later. Upload reports, datasets, and deliverables. Invite the human stakeholders. Everything is organized, searchable, and versioned.

For full details on AI chat types, file context modes, AI state, and how intelligence affects them, see the AI Chat section below.

Shares

Shares are purpose-built spaces for exchanging files with people outside your workspace. They can exist within workspaces and have three types:

Mode	What It Does	Agent Use Case
Send	Recipients can download files	Deliver reports, exports, generated content
Receive	Recipients can upload files	Collect documents, datasets, user submissions
Exchange	Both upload and download	Collaborative workflows, review cycles

Share Features

• Password protection -- require a password for link access
• Expiration dates -- shares auto-expire after a set period
• Download controls -- enable or disable file downloads
• Access levels -- Members Only, Org Members, Registered Users, or Public (anyone with the link)
• Custom branding -- background images, gradient colors, accent colors, logos
• Post-download messaging -- show custom messages and links after download
• Up to 3 custom links per share for context or calls-to-action
• Guest chat -- let share recipients ask questions in real-time
• AI-powered auto-titling -- shares automatically generate smart titles from their contents
• Activity notifications -- get notified when files are sent or received
• Comment controls -- configure who can see and post comments (owners, guests, or both)

Two Storage Modes

When creating a share with share-create, the storage_mode parameter determines how files are stored:

• room (independent storage, default) -- The share has its own isolated storage. Files are added directly to the share and are independent of any workspace. This creates a self-contained data room -- changes to workspace files do not affect the room, and vice versa. Use for final deliverables, compliance packages, archived reports, or any scenario where you want an immutable snapshot.

• shared_folder (workspace-backed) -- The share is backed by a specific folder in a workspace. The share displays the live contents of that folder -- any files added, updated, or removed in the workspace folder are immediately reflected in the share. No file duplication, so no extra storage cost. To create a shared folder, pass storage_mode=shared_folder and folder_node_id={folder_opaque_id} when creating the share. Note: Expiration dates are not allowed on shared folder shares since the content is live.

Both modes look the same to share recipients -- a branded data room with file preview, download controls, and all share features. The difference is whether the content is a snapshot (room) or a live view (shared folder).

Shares are identified by a 19-digit numeric profile ID.

Agent use case: Generate a quarterly report, create a Send share with your client's branding, set a 30-day expiration, and share the link. The client sees a professional, branded page with instant file preview -- not a raw download link.

Storage Nodes

Files and folders are represented as storage nodes. Each node has an opaque ID (a 30-character alphanumeric string, displayed with hyphens, e.g. f3jm5-zqzfx-pxdr2-dx8z5-bvnb3-rpjfm4). The special value root refers to the root folder of a workspace or share, and trash refers to the trash folder.