> ## Documentation Index
> Fetch the complete documentation index at: https://executioncontrolprotocol.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Relationship to MCP

> How ECP builds on the Model Context Protocol

ECP is designed to **embrace and extend** the [Model Context Protocol (MCP)](https://modelcontextprotocol.io). It does not replace MCP.

## What MCP standardizes

* **Tool discovery** — Servers expose tools with names and schemas.
* **Tool invocation** — Clients call tools with structured arguments.
* **Structured tool outputs** — Results are machine-readable.

## What ECP adds

ECP does not redefine tool calling. Instead, it:

* **References MCP servers** — Contexts declare which servers (by name) an executor can use.
* **References MCP tool names** — Policies allow or deny specific tools (e.g. `jira:issues.search`).
* **Uses structured argument schemas** — Mounts and tool calls use JSON Schema-compatible definitions.
* **Bundles permissions and policies** — Default-deny tool access, budgets, write controls per executor.
* **Adds versioning and packaging** — A Context is a versioned, portable manifest (like a container image).

## Layered view

| Layer   | Responsibility                      |
| ------- | ----------------------------------- |
| **MCP** | Tool discovery and invocation       |
| **A2A** | Agent-to-agent communication        |
| **ECP** | Orchestration and execution control |

If MCP is the "USB interface" for AI tools, ECP is the "container manifest" that defines the whole execution environment: which tools, which data (mounts), which guardrails (policies), and how executors coordinate.

## Building with both

* Implement or use **MCP servers** for your data and tools.
* Define **ECP Contexts** that reference those servers, declare mounts and policies, and orchestrate agents that call MCP tools.

This keeps tool semantics in MCP and execution semantics in ECP.

## Related reading

* [Alternatives and comparisons](/alternatives) — ECP (Execution Control Protocol) vs other frameworks