# `A2UICore.Schema.Source`
[🔗](https://github.com/a2ui-elixir/a2ui/blob/v0.1.1/umbrella/apps/a2ui_core/lib/a2ui_core/schema/source.ex#L1)

Loads the A2UI protocol's own JSON Schema documents — vendored under
`priv/` from a pinned revision of the specification — plus the shipped
basic catalogs.

Documents are read once and cached in `:persistent_term` (they are
immutable, process-free data). The vendored copies are the single
source of truth for envelope validation.

## Layout

    priv/schemas/v0_9/*.json       v0.9 wire schemas (server_to_client, …)
    priv/schemas/v0_9_1/*.json     v0.9.1 wire schemas
    priv/schemas/v1_0/*.json       v1.0 wire schemas (agent_to_renderer, …)
    priv/catalogs/basic_v0_9_1.json    basic catalog, protocol version 0.9
    priv/catalogs/basic_v1_0.json      basic catalog, protocol version 1.0
    priv/catalogs/testing_v1_0.json    upstream `testing_catalog.json`
    priv/catalogs/mcp_v0_9.json        MCP catalog, protocol version 0.9
    priv/catalogs/mcp_v1_0.json        MCP catalog, protocol version 1.0

# `document`
*since 0.1.0* 

```elixir
@type document() :: A2UICore.Schema.schema()
```

# `catalog`
*since 0.1.0* 

```elixir
@spec catalog(
  A2UICore.Version.protocol_version() | String.t(),
  :basic | :testing | :mcp
) ::
  document() | nil
```

Loads a shipped catalog by protocol version.

    :basic      the basic catalog for the given protocol line
    :testing    the upstream spec-test catalog (v1.0 only)
    :mcp        the MCP catalog for the given protocol line

# `document`
*since 0.1.0* 

```elixir
@spec document(A2UICore.Version.protocol_version() | String.t(), atom() | String.t()) ::
  document() | nil
```

Loads a wire-schema document by version and logical name.

Logical names normalize the v0.9/v1.0 file renames:

    :agent_to_renderer   v0.9.x -> server_to_client.json
                        v1.0   -> agent_to_renderer.json
    :renderer_to_agent   v0.9.x -> client_to_server.json
                        v1.0   -> renderer_to_agent.json
    :common_types        common_types.json
    :capabilities        v0.9.x -> server_capabilities.json (agent side)
                        v1.0   -> agent_capabilities.json
    :renderer_capabilities  v0.9.x -> client_capabilities.json
                            v1.0   -> renderer_capabilities.json
    :data_model          v0.9.x -> client_data_model.json
                        v1.0   -> renderer_data_model.json
    :list                v0.9.x -> server_to_client_list.json
                        v1.0   -> agent_to_renderer_list.json
    :wrapper             v0.9.x -> server_to_client_list_wrapper.json
                        v1.0   -> agent_to_renderer_list_wrapper.json
    :catalog_definition  v1.0   -> catalog_definition.json (nil for v0.9.x)

Any concrete file name (e.g. `"sample.json"`) is loaded verbatim.

# `ordered_catalog`
*since 0.1.0* 

```elixir
@spec ordered_catalog(
  A2UICore.Version.protocol_version() | String.t(),
  :basic | :testing | :mcp
) ::
  Jason.OrderedObject.t() | nil
```

Like `catalog/2`, decoded with its key order (`Jason.OrderedObject`s),
which orders the components and functions of a catalog built from it
(`A2UICore.Catalog.from_json/2`). Not cached.

# `ordered_document`
*since 0.1.0* 

```elixir
@spec ordered_document(
  A2UICore.Version.protocol_version() | String.t(),
  atom() | String.t()
) ::
  Jason.OrderedObject.t() | nil
```

Like `document/2`, decoded with its key order (`Jason.OrderedObject`s),
for writing the document out in the order it is published in.

# `priv_dir`
*since 0.1.0* 

```elixir
@spec priv_dir() :: Path.t()
```

Returns the priv directory holding the vendored documents.

---

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