dsh-delete-session

Permanently delete a single session from the DeepSeek Harness Web sidebar — one extra entry in the session row's ⋯ menu.

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dsh-delete-session adds a Delete session action to the sidebar session-row menu (next to Rename / Fork / Archive) and permanently removes that session's transcript from disk.

It does this without replacing or disabling any official plugin row and without taking over any host service, so it cannot break the plugin tree the way a service-replacing plugin can.

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Features

Permanent delete	Removes the session's per-session JSONL transcript directory from disk. No recycle bin, no undo.
Confirmation is mandatory	A modal naming the session is required, and the request carries a non-simple custom header that a plain HTML form or link cannot forge.
Running sessions are stopped first	The live agent is torn down through its owned host handle; persistence is drained and the session is verified detached before any file is touched.
Bookkeeping reconciled	The session is detached from its workspace, removed from the archive set, and the UI is told to drop the row — no manual refresh needed.
Zero takeover	The bundle inserts exactly one plugin row. It disables nothing, replaces nothing, and publishes no service.
Theme-aware	The confirmation dialog uses DSH's own theme variables, so it follows light and dark mode automatically.
Localised	Menu entry and dialog follow the host locale (zh / en) through the host locale service, with a built-in fallback table when that service is absent.

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Requirements

• DeepSeek Harness with the Web profile (dsh web).
• The per-session JSONL persistence backend (session-persistence-jsonl), which is the stock backend.
• Verified against DSH 0.1.5-rc.2. The delete route is fail-soft: if a precondition is missing the route is simply not registered and the UI reports a request failure — the plugin never throws during activation.

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Install

# from a git checkout
dsh plugin --profile web add github:masknull/dsh-delete-session

# or from a local directory
dsh plugin --profile web add link:/path/to/dsh-delete-session

Restart dsh web afterwards so the plugin tree is recomposed.

Uninstall

dsh plugin --profile web remove dsh-delete-session

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Motivation

All that was needed was the delete action. Session-management plugins of this kind usually bundle a whole suite along with it — archiving, restore, search — and there were also intermittent dsh web startup failures that took an afternoon to pin down. Since only deletion was needed, this plugin was written separately to do exactly that and nothing else.

How it works

DSH currently exposes no public API for deleting a session: ctx.workspaceRegistry offers archiveSession (soft, marker-only) and deleteKnown (which deletes a workspace, not a session), and the api-session-controller remote surface has create / rename / fork / list / search — but no delete. On top of that, the session-row ⋯ menu is not an extension point: its items are hardcoded inside the official ui-workspace SessionNodeItem, and no slot exists anywhere inside a session row.

So instead of forking the official UI, this plugin uses two DOM seams that were verified live against the running Web UI:

1. Open menu → React fiber ownership. The session-row menu, the view-options (grouping) menu and the workspace-row menu are all the same Menu portal component sharing one [role="menu"] DOM under document.body — DOM structure alone cannot tell them apart. The open menu element's React fiber chain still reaches its owner, and only a SessionNodeItem owner (memoizedProps carrying node.id plus onRename, a shape unique in the client tree) is eligible for injection. The session id and title are resolved from those props at injection time; there is no cached "last clicked row" state that could go stale and act on the wrong session.
2. The menu items themselves. Class names are copied from a live official item at runtime, so the entry inherits the real styling even though the generated class hashes change between builds. The icon is the official IconTrashOutline16 geometry lifted from the shipped frontend bundle, so it matches the three native icons.

If either seam is gone (a future official UI change), the entry is simply never injected — the plugin never falls back to guessing a session id.

Host side

One route: POST /plugins/dsh-delete-session/delete.

The deletion itself is a port of dsh-chat-manager's implementation (MIT — see License), which is careful in ways worth keeping:

• the target path must be exactly three segments under the session root, with the transcript filename matching the JSONL generation pattern;
• the session directory is atomically renamed into a quarantine directory, then its identity is re-verified via dev/ino/mode/size/birthtimeNs before the recursive delete (defence against TOCTOU and symlink swaps);
• a live agent is disposed through the handle captured from agents.create / resume / enter, and a reservation refuses to reopen the session while its deletion is in flight;
• the request boundary enforces POST-only, same-origin, the confirmation header, JSON content type, an 8 KB body cap, and session-id shape.

Added on top of the port: after the physical delete, the plugin reconciles accounting through public API — workspace.list() → find the owning entity → entity.detachSession(id) (public, idempotent, never touches the session log), then removes the id from archivedSessionIds, then emits api-session/removed so the official client drops the row.

What is not deleted

The projection cache row (session_projcache) is intentionally left behind. The session list is built from a disk scan plus a host/client double join filter, so an orphaned cache row never renders as a visible entry. Cleaning it would require replacing the official session-projection-cache service — exactly the kind of takeover this plugin exists to avoid.

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Theming

The confirmation dialog takes every colour from DSH's own theme variables. Those are declared on <body> and re-declared under body[data-ds-dark-theme], so one declaration follows both themes:

Purpose	Variable
Dialog surface	--dsw-specific-menu → --dsw-alias-bg-layer-3
Primary text	--dsw-alias-label-primary
Border	--dsw-alias-border-l2
Danger	--dsw-alias-state-error-primary
Scrim	--dsw-alias-bg-mask-1
Shadow (carries the 0.5px hairline)	--dsw-elevation-panel
Font	--dsw-font-family

Two traps learned the hard way, both documented in README.zh.md:

• Do not invent variable names. The first release used plausible-looking names such as --dsw-alias-bg-elevated; they do not exist, so the surface fell back to a hardcoded dark grey while the text variable did resolve to the theme's dark colour — producing dark-on-dark in light mode.
• Variables live on <body>, not :root. Reading them from document.documentElement returns empty strings.

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Troubleshooting

The plugin depends on the two DOM seams above. If an official UI change removes either one, the symptom is the entry missing from the menu — never a wrong deletion.

Check, in order:

1. Is the open menu still a [role="menu"] element whose fiber chain still reaches props carrying node.id plus onRename (the session row's menu)?
2. Is the popup still [role="menu"] with [role="menuitem"] items?
3. Does React still attach fibers to DOM nodes (__reactFiber$ / __reactInternalInstance$ prefixes)?

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License

MIT. The deletion implementation under src/host/ is ported from dsh-chat-manager (MIT); each ported file keeps a header stating its origin and the changes made.

Acknowledgements

Thanks to dsh-chat-manager: this plugin's core is built on its Host-side deletion implementation. The genuinely hard parts — capturing the agent handle, the quarantine rename with dev/ino identity re-checks, and the request boundary — were already solved well there, which is exactly why this plugin could stay this small.

Thanks as well to the DeepSeek Harness team: the theme variables, the locale service, and the IconTrashOutline16 geometry used here all come from the official frontend.