v0.40.0 — The first composed rune

Implement SPEC-158. IDENTITY_FIELDS (packages/transform/src/identity-fields.ts) becomes a list of paths, and findReservedFields resolves a wildcard segment. This adds three protections:

SPEC-145 D2a. A composed rune has no BEM block and ships no CSS, but it still needs an engine config: its modifiers, universal attributes and meta blocks have to render. Today RuneConfig.block is required. The engine builds ${prefix}-${config.block} unconditionally (packages/transform/src/engine.ts), so a config without one emits rf-undefined. A rune with no config at all leaks data-rune-fields into the HTML.Make block optional:

SPEC-145 D10a, landed ahead of composition so it can be proved inert.Markdoc keeps only the attributes a node's schema declares. A marker set on a node before a primitive transforms it is therefore dropped, unless every node and tag schema declares it. Declare data-owner and data-slot once, at config assembly, on every node and tag schema, never per rune. Teach the schema-table resolvers (packages/runes/src/lib/schema-table.ts) to admit a node past a boundary by data-owner plus data-slot. A primitive's own data-name on the same node is left alone.In the output, releaseOwnedNodes strips data-owner and keeps data-slot (D10a step 4, D10c).Nothing sets either attribute yet, so the gate is that nothing moves. The survival test runs the markers through every rune in D12's placement set. That set is "no peer schema, no requiresParent". Any rune that drops either attribute is a finding, named by the test.

Every rejection SPEC-145 decides at definition load or schema construction, in one place, so that a bad definition fails with its rune and the offending name rather than rendering silently wrong. Between them, D11 and D26 match every content-model field to exactly one slot.The bulk of this item is the error messages. Each check names the rune and the thing it rejected, and the tests assert the message as well as the throw.

The first composed rune: SPEC-145's small worked example, the ~17-line definition that replaces plugins/storytelling/src/tags/bond.ts. The slice uses:

SPEC-153 implementation note 1: the packaging prerequisites everything else in that spec rests on. All three failures are invisible in the monorepo, so this step must not be assumed. Measured in SPEC-153:

SPEC-153 implementation note 2. It is the only gate that catches the measured breakages, and nothing like it exists today. A monorepo test resolves packages through workspace links, so it passes whatever the tarball contains.The harness packs a plugin, installs the tarball into a temporary fixture project outside the workspace, and loads it through the same loadPlugin() path a site uses. The first target is the plugins as they ship today. That proves the harness on known-good input, and proves WORK-626's fix against the tarball rather than the workspace. Shipping composed runes in a tarball is a later SPEC-153 step that reuses this harness.

SPEC-145 D25 bans schema in user composition definitions until a mechanical check exists, and names the candidate: