prometeu-studio/docs/specs/studio/6. Project Document VFS Specification.md

Project Document VFS Specification

Status

Active

Applies To

• prometeu-vfs
• prometeu-studio
• the Studio project-document boundary for the first Code Editor migration wave

Purpose

Define the normative Studio contract for prometeu-vfs as the project-document boundary consumed by Studio workspaces.

This specification stabilizes:

• prometeu-vfs module role,
• project-session ownership,
• the filesystem-backed first-wave contract,
• structural tree and document access responsibilities,
• the RPC-first public API baseline,
• and explicit first-wave exclusions such as public event publication and watchers.

Authority and Precedence

This specification extends:

• 1. Studio Shell and Workspace Layout Specification.md
• 5. Code Editor Workspace Specification.md

If this document conflicts with shell-wide Studio rules, the shell specification controls shell-wide behavior and this document controls the project-document boundary contract.

Normative Inputs

prometeu-vfs must assume:

• the current migration wave carries only the Code Editor capabilities that already exist today,
• the initial backend is filesystem-backed,
• the boundary is project-scoped rather than product-global,
• the boundary must outlive workspace focus changes for an opened project,
• Studio UI remains the owner of visual tree state and error presentation,
• and future consumers such as prometeu-lsp may depend on this boundary later.

prometeu-vfs must not infer:

• watcher-driven refresh in this wave,
• public event API exposure in this wave,
• write or save semantics,
• or ownership over non-Studio domains such as packer assets.

Module Role

prometeu-vfs is:

• the Studio project-document boundary,
• the owner of project structural tree data for the covered scope,
• the owner of project document resolution for the covered scope,
• the owner of file support and unsupported-file classification for the covered scope,
• and the required path through which Studio accesses project-document filesystem state in this wave.

prometeu-vfs is not:

• a visual tree control,
• a Studio shell replacement,
• a product-wide universal filesystem layer,
• or a public event transport in this wave.

Project Session Ownership

The primary prometeu-vfs instance must belong to the Studio project session.

Rules:

• a project-scoped prometeu-vfs instance must be created when a Studio project session is opened;
• that instance must remain alive while the project session remains open;
• switching workspace focus must not destroy or recreate the project-document state by default;
• the Code Editor workspace must consume the session-owned prometeu-vfs instance rather than owning the boundary lifecycle itself;
• the project-session scope must cover only the opened project.

Filesystem Access Rules

For the scope covered by this specification, Studio must access the project filesystem through prometeu-vfs.

Rules:

• the first implementation must be filesystem-backed;
• direct filesystem reads for project tree and document loading must not remain a workspace-owned responsibility in the Code Editor;
• this rule does not grant prometeu-vfs ownership over unrelated domains or unrelated filesystem responsibilities elsewhere in the product.

Structural Tree Contract

prometeu-vfs must expose a structural representation of the project tree.

Rules:

• the structural tree must cover project content only;
• the structural tree must contain structural and documentary data only;
• the structural tree must not contain visual presentation state;
• the structural tree must not contain navigator chrome decisions;
• the structural tree may include structural metadata useful to Studio consumers;
• consumers may request narrower refreshes than a full-tree reload when the request remains within the project boundary.

The following concerns remain outside prometeu-vfs:

• visual expansion state,
• selection state,
• focus state,
• reveal or scroll behavior,
• icon choice,
• and other view-model concerns of the navigator UI.

Document Access Contract

prometeu-vfs must own document resolution for the covered Studio scope.

Rules:

• opening a supported file in the Code Editor must go through prometeu-vfs;
• the returned document content must describe only project-session document state for the opened project;
• this wave must not add save, dirty tracking, merge, or conflict semantics by implication;
• future in-memory overlays may be added only by later explicit decision.

Support and Plugin Rules

Support and unsupported-file decisions belong to prometeu-vfs.

Rules:

• file support classification must be decided inside prometeu-vfs;
• plugin or handler resolution for supported file access must be decided inside prometeu-vfs;
• Studio UI may render the resulting success or failure state, but it must not own the classification rule itself.

Communication Model

The official first-wave prometeu-vfs API is RPC-oriented.

Rules:

• commands and queries are the public API baseline for this wave;
• internal runtime events may exist inside prometeu-vfs;
• those events must remain internal in this wave;
• internal events must not be promoted to public API by inference during planning or implementation.

Refresh and Watchers

Refresh remains manual in this wave.

Rules:

• Studio consumers may request manual refresh through prometeu-vfs;
• watcher-driven automatic refresh is deferred;
• file watching must not be introduced implicitly while implementing this specification.

Cross-Domain Boundary

prometeu-vfs belongs to the Studio domain.

Rules:

• prometeu-vfs may later serve prometeu-lsp as a consumer-facing substrate;
• prometeu-lsp remains a separate layer and must not be renamed into prometeu-vfs;
• prometeu-vfs must not absorb packer responsibilities;
• prometeu-vfs must not redefine asset ownership;
• extending this boundary outside project-document concerns requires a new decision.

Non-Goals

• public event publication
• watcher-driven refresh
• write or save behavior
• dirty tracking
• merge or conflict handling
• non-project content snapshots
• a generic product-wide filesystem abstraction

Exit Criteria

This specification is complete enough when:

• prometeu-vfs ownership is clearly separated from shell and workspace UI ownership,
• the project-session lifecycle rule is unambiguous,
• the structural tree contract is explicitly non-visual,
• the RPC-first public API rule is explicit,
• and deferred public events and watchers are clearly out of scope.