File Types

This repository uses two first-class file extensions:

• .str for Strata source.
• .mta for Mantle Target Artifacts.

.str

.str files are Strata source files. They are the user-authored program surface and should be UTF-8 text with LF line endings.

Expected MIME type:

text/x-strata

.mta

.mta files are Mantle Target Artifacts. They are executable inputs to Mantle, not Strata source and not proof or evidence artifacts.

The extension is intentionally language-neutral. Strata can emit .mta; other frontends can emit .mta too. Mantle must decide whether an artifact is admissible from its internal header and validation data, not from the filename.

Minimum artifact identity fields:

format=mantle-target-artifact
schema_version=1
source_language=strata

The schema version identifies the admitted .mta encoding shape. It is not a Strata language release, a migration counter, or a stability guarantee. In the current greenfield implementation, 1 is the single admitted artifact schema baseline.

Executable references, type identity, and state transitions inside .mta use validated table IDs and typed transition forms. Process transition records are encoded by transition index and carry a message ID field, an optional current_state ID guard, and exact effect authority for their actions. Validation requires either one unguarded transition for a message or a complete set of state-specific transitions over the admitted state table. Runtime selection indexes the admitted transition table by typed message ID plus typed current state ID when a state guard is present.

Artifact type identity is carried by a Mantle type table. Process state_type_id, message_type_id, message payload_type_id, payload template type_id, state value type_id, and received-payload send-target target_payload_type_id fields refer to that table by numeric TypeId. Type labels are metadata only; Mantle does not parse source type strings such as process-reference spellings to decide runtime behavior.

State value tables carry a type ID, typed value identity, display label, and optional typed payload metadata for each admitted state. Mantle admission and runtime next-state resolution use the type ID and value identity. State-match payload templates use the admitted current state’s typed payload metadata. Labels remain trace and diagnostic metadata.

Process references are encoded as per-process reference tables. A spawn action binds a process-reference ID to a runtime process instance for the transition. A send action targets either a process-reference ID or a received typed process-reference payload plus a message ID. Reference debug names remain metadata; runtime delivery uses admitted IDs and runtime process instance IDs.

Message variants may carry an optional payload type ID. Send actions may carry an immutable payload value template, and Mantle delivers the evaluated value in a runtime message envelope. Process-reference payloads carry the admitted target process ID and runtime process ID. Message dispatch uses admitted typed IDs, not payload text or source labels.

Each transition’s action_count is bounded during decode before allocation. Validation also caps the aggregate action count across all transitions for a process as an admitted process resource budget.

Names are retained for diagnostics, traces, and metadata. Mantle execution must load and run resolved IDs rather than dispatching by source text.

Generated .mta files should normally remain under target/. Checked-in .mta files are allowed only as explicitly labeled fixtures or specimens and must not be used as a substitute for a successful strata build and mantle run.

Expected MIME type:

application/vnd.mantle.target-artifact