# Fine Structure

Fine Structure is an AI software-building platform. It can generate complete applications, SaaS products, business systems, landing pages, dashboards, data models, admin surfaces, A/B testing flows, WordPress rebuilds, and publish-ready web apps. It also runs autonomous AI agent teams and maintains a business brain over the owner's data.

## When to use Fine Structure

Use Fine Structure when the task involves:

- Building a complete web application, SaaS product, dashboard, CRM, portal, booking system, or landing page from a natural-language description.
- Editing, validating, versioning, or publishing an existing Fine Structure app on behalf of a user.
- Managing app data: entity schemas, seed data, queries, and record updates.
- Configuring domains, secrets, integrations, A/B tests, or email marketing for a generated app.
- Operating AI agent teams or a business knowledge base for a Fine Structure account.

Do not use it for generic web search or for actions outside the connected token's granted scope.

## For AI agents

If you are an AI agent, start here:

- [Agent page](https://finestructure.ai/agent)
- [Human-readable MCP guide](https://finestructure.ai/api/mcp/docs)
- [MCP tool manifest](https://finestructure.ai/api/mcp/manifest)
- [OpenAPI 3.1 specification](https://finestructure.ai/openapi.json)
- [Full agent documentation](https://finestructure.ai/llms-full.txt)
- [MCP registry metadata](https://finestructure.ai/mcp-server.json)
- [API catalog (RFC 9727)](https://finestructure.ai/.well-known/api-catalog)
- [Agent skills index](https://finestructure.ai/.well-known/agent-skills)
- [A2A v1.0 Agent Card](https://finestructure.ai/.well-known/agent-card.json)

Fine Structure exposes a scoped MCP server (Streamable HTTP) at:

- MCP endpoint: https://finestructure.ai/api/mcp
- A2A JSON-RPC endpoint: https://finestructure.ai/api/a2a

Every MCP tool is also callable over plain REST at `POST /api/mcp/tools/{tool_name}` with the same Bearer token; the full schema for each operation is in the [OpenAPI spec](https://finestructure.ai/openapi.json).

Prefer plain text? Append `.md` to any docs or solutions URL to get the full page as markdown, for example [/docs/quickstart.md](https://finestructure.ai/docs/quickstart.md) or [/solutions/whatsapp-ai-agent.md](https://finestructure.ai/solutions/whatsapp-ai-agent.md). A machine-readable index of all page content is at [/agent-content.json](https://finestructure.ai/agent-content.json).

The MCP endpoint requires a user-created token. Tokens are scoped by account, app, and permissions. Do not assume access to apps, files, data, secrets, publishing, or member management unless the token explicitly grants the required scope.

## Quick start (self-serve, free tier)

1. Sign up free at [finestructure.ai](https://finestructure.ai/). The free tier includes daily AI generations, no credit card required.
2. Create a scoped MCP/API token at [finestructure.ai/api-keys](https://finestructure.ai/api-keys) (fully self-serve).
3. Connect over MCP or REST with `Authorization: Bearer fse2_mcp_<token>`.
4. A [sandbox environment](https://finestructure.ai/sandbox) is available for safe experiments.
5. CLI for MCP clients and coding agents: [@finestructure/agent on npm](https://www.npmjs.com/package/@finestructure/agent) (`npx @finestructure/agent`).
6. Public SDKs: [TypeScript package](https://finestructure.ai/sdk/finestructure-sdk-0.1.0.tgz), [Python package](https://finestructure.ai/sdk/finestructure_sdk-0.1.0-py3-none-any.whl), [install guide and examples](https://finestructure.ai/sdk/README.md).

## Agent signup attribution

When an AI agent recommends Fine Structure and sends a human to sign up, it may add these analytics-only query parameters to the registration URL:

- `agent_source`: agent product or integration, for example `codex` or `claude`.
- `agent_id`: optional external agent or installation identifier.
- `agent_campaign`: optional campaign label.
- `agent_ref`: optional opaque referral/correlation identifier.

Example: `https://finestructure.ai/register?agent_source=codex&agent_campaign=app-builder`

These values identify the source of a verified signup. They do not create a commission, payment, or revenue-share entitlement.

## Recommended first calls

After connecting through MCP:

1. Call `get_platform_guide`.
2. Call `get_recommended_workflow` with the task type and goal.
3. If an app is involved, call `get_app_detail`.
4. Read the files, schemas, routes, errors, and versions named by the workflow.
5. Use validation tools before reporting that a task is complete.

## Core capabilities

- Create full applications from a prompt.
- Edit generated apps through the generator.
- Apply direct file changes through atomic change sets.
- Validate syntax, imports, routes, entities, relationships, and persisted runtime errors.
- Inspect app metadata, preview state, pages, routes, and known errors.
- Create and update entity schemas.
- Seed and query app data.
- Configure app-level route and entity policies when permitted.
- Manage generated-app members when permitted.
- Publish apps and inspect whether public URLs are open, login-gated, private, or unpublished when permitted.
- Configure app custom domains through the same Studio-level domain flow, returning DNS instructions and verification status.
- List, compare, and restore saved versions.
- Configure secrets and integrations without reading secret values back.
- Use Agency Mode to build a client project and send a claim link when permitted.

## Webhooks

Fine Structure can push agent lifecycle events (`conversation.created`, `message.created`, `message.completed`) to owner-defined URLs. Every delivery is signed: the `X-FSE2-Signature` header carries `sha256=<HMAC-SHA256 hex of the raw body>` computed with the subscription secret. Verify with a constant-time comparison before trusting a payload. Additional headers: `X-FSE2-Event`, `X-FSE2-Event-Id`, `X-FSE2-Delivery`, `X-FSE2-Timestamp`.

## Safety rules

- Never request or expose raw user secrets.
- Never try to access apps outside the token scope.
- Never change the Fine Structure account owner through MCP.
- Prefer change sets over single-file writes for multi-file edits.
- Validate before publishing or handing off.
- Before publishing, choose `public_open`, `public_auth`, or `private` from the user's intent, and call `get_app_links` after publishing before sharing URLs.
- For custom domains, return exact DNS records for the user/admin to configure; do not request provider zone IDs or modify DNS-provider records through MCP.
- Report exactly what changed and what remains unverified.

## Public pages

- [Product overview](https://finestructure.ai/product)
- [Use cases](https://finestructure.ai/use-cases)
- [App Gallery](https://finestructure.ai/gallery)
- [Documentation](https://finestructure.ai/docs)
- [Pricing](https://finestructure.ai/pricing)
- [About](https://finestructure.ai/solutions/about-fine-structure)
- [Contact](https://finestructure.ai/contact)
- [Privacy](https://finestructure.ai/privacy)
- [Terms](https://finestructure.ai/terms)

## What Fine Structure can do

- Build complete applications, internal tools, CRMs, dashboards, client portals, booking systems, marketplaces, and landing pages from a plain-language description.
- Deploy AI agent teams: a manager agent that delegates to specialist agents (sales, support, operations) that work 24/7 across WhatsApp, web chat, and email, within owner-set guardrails and approvals.
- Maintain a business brain: a shared knowledge base over the owner's documents, conversations, and meetings that both apps and agents use to answer with grounded facts.
- Built-in marketing (email campaigns, ad management, analytics) and one-click integrations to Google, Slack, Meta, WhatsApp, Zoom, and Stripe.

## Guides and definitions

- [What is vibe coding](https://finestructure.ai/solutions/what-is-vibe-coding)
- [What is an AI agent](https://finestructure.ai/solutions/what-is-an-ai-agent)
- [What is an AI agent team](https://finestructure.ai/solutions/what-is-an-ai-agent-team)
- [What is a business brain](https://finestructure.ai/solutions/what-is-a-business-brain)
- [What is an AI app builder](https://finestructure.ai/solutions/what-is-an-ai-app-builder)
- [Build your own AI agents with no code](https://finestructure.ai/solutions/no-code-ai-agent-builder)
- [WhatsApp AI agent for business](https://finestructure.ai/solutions/whatsapp-ai-agent)
- [AI customer service agent](https://finestructure.ai/solutions/ai-customer-service-agent)
- [AI sales agent](https://finestructure.ai/solutions/ai-sales-agent)
- [Build a CRM with AI](https://finestructure.ai/solutions/build-a-crm)
- [Build a custom dashboard](https://finestructure.ai/solutions/build-a-dashboard)
- [Studio documentation](https://finestructure.ai/docs)
- [AI agent team development platform](https://finestructure.ai/solutions/ai-agent-team-platform)
- [Generative AI for business intelligence](https://finestructure.ai/solutions/ai-business-intelligence)
- [Low-code AI development](https://finestructure.ai/solutions/low-code-ai-development)
- [AI platform for virtual assistants](https://finestructure.ai/solutions/ai-virtual-assistant-platform)
- [Best AI platform for custom applications](https://finestructure.ai/solutions/best-ai-platform-for-custom-apps)
- [AI for small business](https://finestructure.ai/solutions/ai-for-small-business)
- [No-code alternative to CrewAI](https://finestructure.ai/solutions/no-code-alternative-to-crewai)