Jacquard Core 0.3 Limits

Jacquard 0.3 is a research prototype. These limits are part of the release, not a future-work appendix to omit from public descriptions.

Language and Compatibility

The 27-form kernel, .jqd carrier, HASH_V0, native 63-bit wrapping integers, UTF-8-without-normalization rule, splitmix64-derived seeded PRNG, and uncurried final-call convention remain as documented.
Public .jac is implemented and supported, but is still an evolving v0 projection. 0.3 does not promise that every future surface program will parse unchanged.
Broader macros beyond quote/unquote/gated eval, typed staging, continuous distributions, gradients, language package management, self-hosting, and ownership/borrowing do not ship.
There is no formal type-soundness, handler-soundness, serialization, or compiler-correctness proof.
Records beyond nominal labeled constructors, operators, trait-style overloading and implicit dictionaries do not ship; accessors, setters and field updates are generated over ordinary constructors.

Local projects are not a package manager: there is no registry, version resolution, download, or semantic-version solver. Dependencies are local paths or bundles pinned by context identity, and pins and bundles are bound to the exact Core version that made them.
Project visibility and opaque types are language access control for checked code, not concealment. Stores, bundles and run transcripts contain every value’s representation and are readable by anyone with the files.
Opaque-type sealing in a single file protects only within one run and against eval-code; a persistent store is trusted content. In a project, dynamic code runs with the root’s visibility. Value ordering can reveal a representation.
The interface diff classifies any changed exported identity as breaking; it does not decide source or behavioural compatibility.

Language grants constrain the Jacquard runtime; they do not isolate hostile native code, replace filesystem/container permissions, or defend against a compromised runtime, compiler, operating system, or dependency.
Native AOT implements a documented subset. Dynamic Eval, interpreted Task scheduling, and typed Channels are not native execution features.
Parallel hints remain sequential. Structured concurrency is cooperatively scheduled in the interpreter; cancellation is not preemptive, cleanup uses explicit brackets, and ownership/lifetime enforcement is dynamic.
There is no VM/JIT, shared-memory model, select/timeouts, actors, supervision tree, host scheduler, or real asynchronous host I/O runtime.
Computation fuel, the host worker, observation policies and relate are interpreter features. Fuel is opt-in and bounds evaluation steps, not memory or wall-clock time; allocation limits do not ship.
Host protocol v0 is serial and refuses opaque, callable and run-owned values; a sealed-handle protocol does not ship. Host authority below whole-effect grants is a recorded decision, not an enforced boundary.

Exact inference is finite and discrete. Likelihood weighting is approximate sampling evidence; neither mode proves a model is well specified.
Exhaustive Warp and schedule results are exhaustive only within their declared finite support and bounds.
Hashes establish byte or canonical-structure identities under documented encodings. They do not establish truth, authorship, intent, safety, or behavioral equivalence.
The test inventory, fuzz seeds, model-checking bounds, and 50,000-case grid are finite evidence. Passing them does not eliminate untested defects.
The readability benchmark has a protocol and synthetic harness evidence but no human-participant result released here. The documentation-only onboarding exercise is executable but has not been run with an unfamiliar developer.

Workspace v0 and the governance viewer are research reference surfaces, not a production authorization system or security boundary.
Trusted host code owns persistence, locking, identity/authentication, external-state freshness, I/O, provider integration, and final action execution. The language cannot prove that a malicious host obeyed a verdict.
Approval decisions bind exact proposal artifacts and reject stale content; they do not authenticate the human without a trusted host identity layer.
Audit chains detect mutation under their hash and publication assumptions; they can preserve false statements faithfully and are not transparency logs or independently witnessed ledgers.
Secret values have an explicit opaque/exposure boundary, but Jacquard does not provide whole-program taint tracking, memory erasure, side-channel resistance, or a production vault.
Approximate Judge results and review-fact projections are evidence for a policy decision, not objective truth.

Design proposals for execution exploration, understandable uncertainty, behavioral change review and single-function embedding are not shipped features.
Published binaries target only Linux x86-64, macOS x86-64, and macOS arm64. Other systems require the source toolchain.
Downloads are checked with SHA-256. The release does not ship a language package manager, automatic update channel, reproducible-build guarantee across arbitrary hosts, or a separate code-signing/notarization system.
The browser governance viewer remains source-checkout-only and offline; it is not deployed as a supported hosted product.