Module mcp 

Typed IR for a schema’s MCP operator surface (ADR 0002, cratestack#1033 phase 1, cratestack#1036).

Three declarations feed it: the top-level mcp { name = "..." expose = [tools, resources] } block (McpConfig, McpName), @mcp(tool[: "name"][, description: "..."]) on a procedure (ProcedureMcpExposure), and @@mcp(resource: "segment"[, max_page_size: N]) on a model (ModelMcpExposure).

These are typed rather than left as Attribute { raw } / a raw-text ConfigBlock because MCP exposure decides what an agent can reach: a declaration that parses and is then read by nothing is the failure mode this IR exists to rule out (ADR 0002 Q4 — @no_idempotency sat inert for two release cycles exactly that way). cratestack-parser extracts the @mcp/@@mcp attributes out of the raw attribute lists when it builds these, so there is one representation to read, never a raw copy that a consumer could re-parse and disagree with.

Every field is Option with #[serde(default, skip_serializing_if)] on its owner, so an IR snapshot written before MCP existed (committed migrations/*/schema.snapshot.json) deserializes unchanged and a schema that declares no MCP serializes byte-identically to before.

Structs

McpConfig

The top-level mcp { } block.

McpName

The name = "..." entry of the mcp { } block.

ModelMcpExposure

@@mcp(resource: "...") on a model: expose it as a read-only MCP resource.

ProcedureMcpExposure

@mcp(tool ...) on a procedure: expose it as an MCP tool.

Constants

MCP_MAX_PAGE_SIZE

Hard ceiling on a collection resource’s page size (ADR 0002 Q3). A model may lower its own maximum with max_page_size:, never raise it past this; a larger value is a validation error, not a clamp.