Image target and artifact projections v1

Status: implemented bounded projection profile; HOSTED GREEN under the v0.4.0 release baseline. Full-programme support and actual target execution remain separate from these compiler projections. Audience: semantic agent clients, compiler contributors, and embedding hosts.

ProjectSemanticImage::target_admission derives actual compiler-emission facts for the selected image's complete linked entry and test programs. It reuses the candidate target producer, including native C11 emission and wasmparser structural validation of Core Wasm. The selected authored function's membership is checked against each retained role program. A whole-closure failure does not establish that this function caused the failure. The report labels this scope and carries the owning compiler diagnostic without claiming runtime execution, native machine-code compilation, standalone function support or failure blame.

artifact_projection(expected_image, ImageArtifactKind::{Web,Npm,OpenApi,C}, max_bytes) invokes the pathless Project carrier builder for the selected kind. The existing manifest/profile decides admission; Web remains scalar Project v1, and npm keeps its existing supported profiles. OpenAPI retains its scalar document profile as described below. The returned carrier is independently replayed before its schema, payload digest, exact envelope SHA256, file paths, byte counts and individual SHA256 bindings are projected. Nothing is installed, executed or written to a filesystem output directory.

Manifest-selected public export stable IDs link to their retained source declarations. Every authenticated source path/digest/revision is also listed as a Project input. These are source/manifest and carrier relationships, not dynamic coverage, proof that every file exports every declaration, external consumer usage, or npm installation evidence. Rust carriers, compiled C libraries and package-consumer migration remain outside this report. The additive OpenAPI artifact kind provides source-bound per-module documents through the existing scalar generator and full Project source replay, while preserving Web/npm report bytes. The additive C artifact kind binds real linked native C11 source to exact header prototypes or explicit exclusions, without changing linkage or claiming a standalone FFI header.

The artifact build/envelope bound is host-selected within 1 KiB–16 MiB. Compact reports are at most 1 MiB and contain no encoded artifact bodies. Existing carrier limits and bounded compiler emitters remain active. These output and construction bounds do not claim a total heap or wall-clock limit.

Both reports bind the exact image and Project revisions. Artifact reports also bind the semantic graph digest, build kind and build bound. verify_artifact_projection regenerates and replays the complete carrier and requires exact report bytes. Report JSON is recursively key-sorted, compact, and has no terminal LF. SPX-G290 rejects selections/offsets, SPX-G291 bounds, SPX-G292 unexpected compiler-carrier bindings, and SPX-G293 report mismatch. Existing source, target and carrier diagnostics remain unchanged where delegated.

Protocol

Image Agent Protocol v5 adds image/target-admission as a semantic_read query. It takes exact image_revision, target, and optional bounded UTF-8 chunk offset/size. candidate/build is exposed only if the host selected both candidate preparation and build authority. It takes a retained candidate, kind web, npm, openapi or c, and chunk controls; requests cannot widen its fixed 16 MiB build bound. The candidate's entire recovery history is independently restored before building and replaying its pathless carrier. It returns artifact-projection chunks, never filesystem materialization or publication authority.

Chunk envelopes identify the full report schema, exact session image and optional candidate/target/kind selections, offset, total bytes and next offset. Existing host source authentication surrounds queries; v5 does not change the method sets of v1–v4. The distinction between build and artifact-materialization authority remains explicit.

tests/image_protocol/target_artifacts_v1.rs covers membership, actual carrier binding, export/source provenance, exact replay/mutation, capacity and no-write checks. These implemented regressions have HOSTED GREEN v0.4.0 release evidence. They validate bounded compiler projections and no-write behavior; they do not turn a pathless artifact report into runtime execution or publication support.

The additive Candidate Artifact Delta v1 compares these actual projections across a replayed candidate's original and final revisions. It preserves this report's bytes and profile admission, and uses the existing v5 build grant for its separate chunked comparison route. The library-only Candidate Analysis Artifact Evidence v1 composes one such exact delta with candidate coverage while keeping materialization, deployment, execution and consumer evidence outside the claim.