fast-io

---
name: fast-io
description: >-
  Workspaces for agentic teams. Complete agent guide with all 19 consolidated
  tools using action-based routing — parameters, workflows, ID formats, and
  constraints. Use this skill when agents need shared workspaces to collaborate
  with other agents and humans, create branded shares (Send/Receive/Exchange),
  or query documents using built-in AI. Supports ownership transfer to humans,
  workspace management, workflow primitives (tasks, worklogs, approvals, todos),
  and real-time collaboration.
  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: "1.123.0"
homepage: "https://fast.io"
---

# Fast.io MCP Server -- AI Agent Guide

**Version:** 1.123
**Last Updated:** 2026-03-16

The definitive 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, metadata, workflow, ownership transfer), 12 end-to-end workflows, interactive MCP App widgets, and all 19 consolidated tools with action-based routing.

> **Versioned guide.** This guide is versioned and updated with each server release. The version number at the top of this document tracks tool parameters, ID formats, and API behavior changes. If you encounter unexpected errors, the guide version may have changed since you last read it.

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

---

## 1. Overview

**Workspaces for Agentic Teams. Collaborate, share, and query with AI -- all through one API, free.**

Fast.io provides workspaces for agentic teams -- where agents collaborate with other agents and with humans. Upload outputs, create branded shares, ask questions about documents using built-in AI, 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

Agentic teams -- groups of agents working together and with humans -- need a shared place to work. Today, agents cobble together S3 buckets, presigned URLs, email attachments, and custom download pages. Every agent reinvents collaboration, and there is no shared workspace where agents and humans can see the same files, track activity, and hand off work.

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 |
|---------|-----------------|
| No shared workspace for agentic teams | Workspaces where agents and humans collaborate with file preview, versioning, and AI |
| Agent-to-agent coordination lacks structure | Shared workspaces with activity feeds, comments, and real-time sync across team members |
| Sharing outputs 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 your workspace -- 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 documents are automatically indexed, summarized, and queryable |
| Finding the right file in a large collection | Semantic search finds documents 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 19 consolidated tools that cover the full Fast.io REST API surface. Every authenticated API endpoint has a corresponding tool action, 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 static MCP resources, widget resources, and file download resource templates. Clients can read them via `resources/list` and `resources/read`:

| URI | Name | Description | MIME Type |
|-----|------|-------------|-----------|
| `skill://guide` | skill-guide | Full agent guide (this document) with all 19 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), `scopes` (raw scope string or null), `scopes_detail` (array of hydrated scope objects with entity names/domains/parents, or null), `agent_name` (string or null) | `application/json` |
| `widget://*` | Widget HTML | Interactive HTML5 widgets (6 total) -- use the `apps` tool to discover and launch | `text/html` |

**File download resource templates** -- read file content directly through MCP without needing external HTTP access:

| URI Template | Name | Auth | Dynamic Listing | Description |
|---|---|---|---|---|
| `download://workspace/{workspace_id}/{node_id}` | download-workspace-file | Session token | Yes | Download a file from a workspace |
| `download://share/{share_id}/{node_id}` | download-share-file | Session token | Yes | Download a file from a share |
| `download://quickshare/{quickshare_id}` | download-quickshare-file | None (public) | No | Download a quickshare file |

Files up to 50 MB are returned inline as base64-encoded blob content. Larger files return a text fallback with a URL to the HTTP pass-through endpoint (see below). The `download` tool responses include a `resource_uri` field with the appropriate URI for each file.

**Dynamic resource listing:** When authenticated, workspace and share file resources are dynamically listed via `resources/list`. MCP clients (such as Claude Desktop's `@` mention picker) can discover available files without any tool calls. Up to 10 workspaces and 10 shares are enumerated, with up to 25 most recently updated root-level files from each. Resources appear as "WorkspaceName / filename.ext" or "ShareTitle / filename.ext". Results are cached for 1 minute per session. Only root-level files are listed -- subdirectories are not recursively enumerated. Use the `storage` tool with action `list` to browse deeper. The quickshare template remains template-only and is not dynamically enumerable.

### MCP Prompts

The server registers MCP prompts that appear in the client's "Add From" / "+" menu as user-clickable app launchers. These are primarily for desktop MCP clients (e.g., Claude Desktop); code-mode clients (Claude Code, Cursor) do not surface prompts.

| Prompt Name | Description |
|---|---|
| `App: Choose Workspace or Org` | Launch the Workspace Picker to browse orgs, select workspaces, and manage shares |
| `App: Pick a File` | Launch the File Picker with built-in workspace navigator for browsing, searching, and selecting files |
| `App: Open Workflow` | Launch the Workflow Manager (auto-selects workspace if only one, otherwise opens Workspace Picker first) |
| `App: Upload Files` | Launch the Uploader to upload files with drag-and-drop, progress tracking, and text file creation |
| `App: Available Apps` | List all available MCP App widgets with descriptions and launch instructions |

### HTTP File Pass-Through

For files larger than 50 MB or when raw binary streaming is needed, the server provides an HTTP pass-through endpoint that streams file content directly from the API:

| Endpoint | Auth | Description |
|---|---|---|
| `GET /file/workspace/{workspace_id}/{node_id}` | `Mcp-Session-Id` header | Stream a workspace file |
| `GET /file/share/{share_id}/{node_id}` | `Mcp-Session-Id` header | Stream a share file |
| `GET /file/quickshare/{quickshare_id}` | None (public) | Stream a quickshare file |

The response includes proper `Content-Type`, `Content-Length`, and `Content-Disposition` headers from the upstream API. Errors are returned as HTML pages. The `Mcp-Session-Id` header is the same session identifier used for MCP protocol communication.

### Workflow Overview

The server includes workflow features for project tracking: **tasks** (structured work items with priorities and assignees), **worklogs** (append-only activity logs), **approvals** (formal sign-off requests), and **todos** (simple checklists). Enable workflow on a workspace with `workspace` action `enable-workflow` before using these tools. See the **Full Agent Workflow** recipe in section 6 for the complete pattern.

**Best practice (IMPORTANT):** After state-changing actions (uploading files, creating shares, changing task status, member changes, file moves/deletes), append a worklog entry describing what you did and why. Without worklog entries, agent work is invisible to humans reviewing the workspace. For multiple related actions (e.g., uploading several files), you may log once after the batch completes rather than after each individual action. Worklog entries are append-only and permanent.

### Additional References

- **

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