# Filesystem, Obsidian, and Charter

## Watched roots

Each filesystem connector is configured with:

- A stable source id.
- One absolute root.
- Include globs.
- Ignore globs.
- Maximum file size.
- Allowed text extensions.
- Whether to store full content, a redacted snapshot, or metadata only.
- Debounce/coalescing window.

The connector refuses paths that escape the root after symlink resolution. `.git`, `.thoughtstream`, caches, lock files, editor temporaries, and configured secret patterns are ignored by default.

## Stable document identity

Identity priority:

1. Explicit frontmatter `id` for Markdown documents.
2. Source-specific inode/device identity when reliable within a scan window.
3. Content hash plus rename-window matching.
4. Normalized source id and relative path.

Path is mutable metadata, not the only identity. A rename emits one rename event where confidently detected; otherwise delete plus add is acceptable and explicitly marked as uncertain.

## Version and diff sequence

For a text addition or change:

1. Read a stable snapshot after debounce and stat verification.
2. Compute SHA-256 and canonical newline-normalized text.
3. If hash matches the current version, emit nothing.
4. Insert an immutable document version.
5. Compute a unified diff against the prior version when bounded by size.
6. Append the file source event referencing previous/current version ids.
7. Update the mutable current-document projection.

Binary and oversized files produce metadata events with no embedded content.

## Obsidian

An Obsidian vault is an ordinary bounded filesystem source with Markdown-aware metadata:

- frontmatter
- headings
- wikilinks and Markdown links
- tags
- blocks/anchors
- optional backlinks calculated as a projection

The first live configuration must point to a selected subtree, not all of The Coil. Private vault content is `sensitive` even when the file itself has no explicit privacy marker.

## Charter bridge

thought stream observes document changes and emits generic file/document events. A Charter-specific consumer can emit `stream.thought.derived.charter.reevaluation` with:

- Changed document/version ids.
- Affected spec ids and links.
- Invariants or decisions that may need re-evaluation.
- Suggested Charter consumer/work-item type.
- Confidence and evidence spans.

Charter may consume this event through a versioned adapter. thought stream does not write Charter's database or spec files in the initial release. Charter remains authority for spec semantics, work items, and any eventual application of changes.

## First fixture

Tests use `fixtures/vault/` with a small linked document graph. The acceptance scenario edits one Markdown file, renames a second, and deletes a third, then verifies exact versions, diffs, lineage, agent outputs, and projection state.