## Why
Skill discovery and metadata loading used raw filesystem handles with unrestricted reads, and cache keys distinguished filesystems without accounting for captured permissions.
## What changed
- Pass borrowed `EnvironmentAccess` accessors through skill root resolution, discovery, canonicalization, and metadata reads.
- Include captured permissions in skill snapshot and empty remote root cache keys.
- Add fixed-path watches to `EnvironmentAccess`, falling back to live discovery when read restrictions prevent using unsandboxed executor watches.
- Keep user and plugin roots under host filesystem authority independently of the selected repository executor.
## Testing
Extend remote root cache coverage to verify that changing captured permissions triggers a fresh scan and that restricted accessors decline unsandboxed watches.
GitOrigin-RevId: 97d4bfdfcba78a93fc8845773c6397d4364494e3
## Why
Cached repository skill metadata must not authorize reads after access is revoked or a skill file or directory becomes a symlink to a denied location.
## What changed
Read repository skill instructions through a current environment accessor for the filesystem that discovered them. Reject reads when no matching accessor is available, and cache filesystem identity instead of retaining unrestricted read access.
## Testing
Add regression coverage for revoked permissions, file and directory symlink replacements, and missing or mismatched filesystem accessors.
GitOrigin-RevId: 8dad83b7c7893e0d66e2fe1c0c240715db582005
## What changed
Add `write_file_stream` to `ExecutorFileSystem` and `EnvironmentAccess`, preserving the accessor's captured sandbox permissions. Local and streaming-capable remote filesystems replace files one bounded chunk at a time and return the byte count. Older executors buffer the input before sending a single `writeFile` request.
Close remote handles on completion or failure, perform best-effort cleanup after cancellation, and invalidate pending metadata lookups. Document that failure or cancellation can leave a truncated or partial file and that in-flight I/O may outlive cancellation.
## Testing
Add coverage for sequential writes, binary and empty files across local and remote filesystems, source failures, handle cleanup, metadata invalidation after cancellation, and compatibility with older executors.
GitOrigin-RevId: d3eb44e0ac2f0f336e9e157d686464f4d45a3f26
## What changed
Add `EnvironmentAccess` and `FileSystemEnvironmentAccessor` to expose filesystem operations with a captured sandbox configuration, without allowing consumers to extract the filesystem or select another sandbox. Include a text-reading helper and an explicit unrestricted constructor.
Provide opaque cache keys that compare filesystem identity and captured permissions without keeping the filesystem alive. Allow opened read streams to outlive the accessor. Export the new APIs through `codex-exec-server` and add `Environment::filesystem_ref()` for borrowing the shared filesystem.
## Testing
Add local and remote coverage for text reads through `EnvironmentAccess`, streams surviving accessor disposal, and cache keys distinguishing changed permissions or a replacement filesystem.
GitOrigin-RevId: 4f6787ed9ba0fb94adea2f31716c4d3132fed07d
Dmitriy Kovalenko