# `A2UICore.Catalog.MCP`
[🔗](https://github.com/a2ui-elixir/a2ui/blob/v0.1.1/umbrella/apps/a2ui_core/lib/a2ui_core/catalog/mcp.ex#L1)

The A2UI MCP catalog, ready to evaluate: the catalog through which a
surface calls [Model Context Protocol](https://modelcontextprotocol.io)
tools.

  * v0.9 (`https://a2ui.org/specification/v0_9/catalogs/mcp/mcp_catalog.json`)
    declares the functions `callMcpTool`, `jmespath`, `split`,
    `regexCapture`, `regexReplace` and `updateDataModel`, and no
    components.
  * v1.0 (`https://a2ui.org/specification/v1_0/catalogs/mcp/catalog.json`)
    declares `callMcpTool` (with `targetDataPath`) and the `McpApp`
    component, which renders an MCP App in a sandbox.

The catalog documents are the vendored published ones
(`A2UICore.Schema.Source.catalog/2`); the functions get their
implementations from `A2UICore.Functions.MCP`. A renderer serves the
catalog next to the basic one: in v1.0 a call or a component names it
by `catalogId`; in v0.9 a surface has one catalog, so the MCP functions
join the basic catalog's in a catalog of the host's own (see
`A2UICore.Catalog.copy_with/2`).

# `catalog`
*since 0.1.0* 

```elixir
@spec catalog(String.t(), keyword()) :: A2UICore.Catalog.t()
```

The MCP catalog for `version` (`"v0.9"`, `"v0.9.1"` or `"v1.0"`), with
its functions implemented.

Options: `:client` — the MCP client `callMcpTool` uses (see
`A2UICore.Functions.MCP.implementations/2`).

# `catalog_id`
*since 0.1.0* 

```elixir
@spec catalog_id(String.t()) :: String.t()
```

The catalog ID of the MCP catalog for `version`.

    iex> A2UICore.Catalog.MCP.catalog_id("v1.0")
    "https://a2ui.org/specification/v1_0/catalogs/mcp/catalog.json"

# `declared`
*since 0.1.0* 

```elixir
@spec declared(String.t()) :: A2UICore.Catalog.t()
```

The MCP catalog for `version` as published: function and component
schemas, no implementations.

# `implement`
*since 0.1.0* 

```elixir
@spec implement(A2UICore.Catalog.t(), String.t(), keyword()) :: A2UICore.Catalog.t()
```

Attaches the MCP functions' implementations and the system functions of
`version` to a catalog that declares them (the MCP catalog, or one that
copies its functions). Functions the catalog does not declare are
ignored.

Options: as for `catalog/2`.

---

*Consult [api-reference.md](api-reference.md) for complete listing*