omdsh-dev/dsh-session-health

中文

DSH session health check plugin — performs frame-level scan diagnostics on multi-frame zstd session files under $DSH_HOME/sessions (torn / corrupted / empty sessions / stray files), and outputs a health report with cleanup suggestions. Read-only: never modifies or deletes any file.

Repository: https://github.com/omdsh-dev/dsh-session-health (public)

Motivation

While investigating issue #376 on 8/7, we ran a full decode analysis over 39 session files and discovered a key fact in the process: DSH session files are a concatenation of multiple zstd frames (a 19MB session = 119,952 frames). Reading a multi-frame file with a single-frame decode API only reveals the header — which once caused a false "all sessions empty" judgment. This diagnostic logic deserves to be productized as a tool: the model can directly ask "is my session file healthy" instead of relying on hand-written scripts.

Complementary to dsh-session-repair-skill (which repairs corrupted sessions): this tool discovers via read-only diagnostics → the repair skill repairs.

Security Model

• Read-only guarantee: never modifies/deletes any file (covered by the "file byte counts unchanged after scanning" test, see the files.spec SH-06 case)
• Path fencing: session ids go through a strict directory-name whitelist (prevents ../ traversal); both the absolute path and the final file pass fs.realpath real-path containment checks (prevents symlink/junction escape); enumeration uses lstat to reject symlinks
• Zero business dependencies: the zstd frame scanner is an independent implementation (reads bytes with DataView, RFC 8878 structure, differential-consistent with the official scanZstdFrames)
• Deep analysis optional: with deep: true the official decoder is dynamically imported; on parse failure it explicitly degrades to deep: "unavailable", never silently
• Fixed input scope (sessions directory), no network, no execution surface

Tool Declaration

Registers the session_health tool (@deepseek-ai/dsh-session-health, row id tool-session-health), uniformly outputting JSON text.

Parameter	Type	Required	Description
action	string	✅	scan / file / stats
path	string		Absolute file path (must be within the sessions root) or session id (required for file/stats)
deep	boolean		Deep analysis (decoded event statistics), default false
detail	boolean		List abnormal files (scan defaults to true); false returns only the summary

Detection Items

Category	Determination
missing	Session id resolves to no file
empty	0-byte file
not-zstd	First 4 bytes are not 28 b5 2f fd (plaintext .jsonl or corrupted)
torn	EOF interrupts a frame tail (interrupted write)
reserved-header / reserved-block	Invalid reserved bits in the frame header/block header (structural corruption)
bad-header	deep mode: the first frame is not a session header
empty-session	Only 1 frame (header) and not updated for over 1 minute
oversized-single-frame	Single frame > 1MB (normal multi-frame writes do not do this)
interrupted	deep mode: has turn/start but no turn/end (process killed/crashed)
stray-file	*.tmp / leftover files with non-standard names

The report contains: root / scanned / errors / suspicious / totals(bytes·frame count·event-batch estimate) / detail / deep / suggestions (suggestions give cleanup/repair advice per the issue template, not executed automatically).

Examples

session_health { action: "scan" }
  → {"root":"C:\\Users\\admin\\.dsh\\sessions","scanned":39,"errors":{...},"suspicious":{...},"suggestions":[...]}

session_health { action: "file", path: "session-abc123", deep: true }
  → 单文件报告（含事件分布与中断检测）

DSH 0.1.5-rc.1 Compatibility (verified)

This plugin has been migrated to the DSH 0.1.5-rc.1 harness, and full end-to-end verification was completed in an isolated consumer of local harness 0.1.5-rc.1:

• Types/runtime: @deepseek-ai/cordis@^4.0.1 + @deepseek-ai/dsh-tools@>=0.0.1-rc.1 <0.2.0 + @deepseek-ai/dsh-invariants@>=0.0.1-rc.1 <0.2.0 (peer); no longer depends on unscoped cordis
• Standalone build: npm install (devDependencies self-contain typescript/vitest/@types/node) → npm run typecheck → npm test → npm run build → npm pack
• Consumption verification: tarball loaded into an rc.8 consumer → the plugin's row appears in dsh --profile compat --dump-config → real tool registration and execution passed
• Startup method: npx -p @deepseek-ai/dsh@next dsh web (lib production mode; do not install -g globally)

Known limitation: under DSH 0.1.5-rc.1, the @deepseek-ai/dsh-session-persistence-jsonl tarball that deep mode depends on still does not include src/, and its root entry still does not export the zstd API; deep degrades to decoder-unavailable; frame-level scanning is unaffected (reported to dsh-external/issues — that organization is org infrastructure and remains in place).

Installation

Under DSH 0.1.5-rc.1, plugins are installed via dsh plugin --profile <profile> add <source>; source is a GitHub repository or an npm pack tarball.

Install from GitHub (Recommended)

# 交互式（web）profile
dsh plugin --profile web add github:omdsh-dev/dsh-session-health
# 一次性任务（headless）profile —— dsh run 默认使用 headless
dsh plugin --profile headless add github:omdsh-dev/dsh-session-health

Install from npm pack tarball

The npm pack artifact can be installed directly as source:

dsh plugin --profile web add dsh-session-health-*.tgz

The bundled dsh.bundle.patch automatically adds the plugin to the profile's layer stack after installation (row id: tool-session-health). The plugin's missing peer dependencies (@deepseek-ai/cordis, @deepseek-ai/dsh-tools) are provided by the profile's healed profiles/node_modules fallback installation.

⚠️ web and headless are different profiles: installing into web does not automatically cover headless; dsh run uses the headless profile by default. Use forward slashes for Windows paths (C:/...).

Verifying the Installation

dsh --profile web --dump-config | grep tool-session-health

Runtime Verification

dsh run "使用 session_health 工具扫描会话目录健康状态"

Legacy Scenario: monorepo / Local-Path Installation

The monorepo approach is now a legacy scenario (local junction/symlink, manually editing the profile layer, legacy snapshots without GitHub/tarball source support):

dsh plugin --profile web add "C:/path/to/dsh-session-health"

Testing

node <monorepo>/node_modules/vitest/vitest.mjs run tests

• zstd-scan.spec.ts: boundaries of frames generated by the official compressor / multi-frame / not-zstd / truncated / reserved bits + real-session differentials (large/medium/small files frame-by-frame identical to the official scanZstdFrames; reads local sessions read-only, not committed to the repo)
• files.spec.ts: two-level directory enumeration, stray/jsonl identification, path fencing (traversal/symlink/out-of-bounds rejection), session id resolution, read-only guarantee
• report.spec.ts: error/suspicious count bucketing, suggestions templates, empty results, deep degradation annotation
• register.spec.ts: registration contract (AUDIT-CROSS-02 style)

Known Limitations

• deep depends on dynamically importing the official decoder: at runtime in a profile, if the package cannot be resolved, it explicitly degrades to frame-level scanning (the report is annotated with deep: "unavailable")
• Event-batch estimate = frame count - 1 (each batch has at least 1 frame; not an exact event count, the report notes it is an estimate)

License

MIT