DSH Context Manager

A standalone plugin for DeepSeek Harness 0.2.0-rc.2 or later. Adds a Context button beside the conversation title, plus /context-manager in the command menu. No desktop source changes, extra background server, or model tool is required.

Use

1. Open Context in an existing conversation.
2. Inspect estimated context usage and its composition: instructions, user messages, answers, stored reasoning, tool/file outputs, tool definitions, and attachment references.
3. Choose Keep, Summarize, or Omit for older history groups. The latest exchange, system/developer instructions, Harness instruction/catalog/runtime snapshots, and incomplete tool exchanges are protected.
4. Choose whether summaries should summarize, retain the original text of, or omit recorded tool/file outputs.
5. Generate a preview. Review the exact replacement text and estimated token change, check the review box, and apply.

Summary requests start with the conversation's most recently routed model and may incur normal model usage. A host plugin can reroute requests marked purpose: 'compaction' to a dedicated summarizer. Changing an unsent composer selection alone does not set the summary model. An omission-only preview does not call the model. A preview makes no change to active context. It expires after ten minutes, a new preview, plugin reload, or a change to the conversation. Apply is permitted only while the agent is idle. A preview that expires or is discarded while the initial save is pending is rejected before any history changes.

Keep applies to this operation. It is not a permanent pin against Harness's automatic compaction. Existing automatic compaction is left in place.

Why balanced history groups?

Model adapters can require reasoning signatures and complete tool-call/result pairs when replaying previous assistant messages. Removing only reasoning from those native messages can invalidate the conversation. This plugin keeps selected exchanges intact or replaces entire balanced ranges with ordinary text checkpoints. It never edits the reasoning or provider metadata of retained messages.

Summary input is a fresh, tool-free text transcript. It excludes reasoning, labels document content as data, and asks the model to preserve goals, decisions, constraints, verified results, paths, and unresolved work. As with any model summary, details may be lost or misrepresented: review the preview before applying.

Files, PDFs, images, and original history

• Tool output includes text returned by file readers, PDF plugins, terminal commands, and other tools. The output option applies to all recorded tool output; it does not infer which text came from a PDF.
• “Keep original text” retains the recorded output text inside the checkpoint. It does not reread the file or retain image pixels.
• Attached images are not visually summarized. Keep the containing group to retain the original attachment.
• Files on disk are never changed or deleted by this plugin.
• Original messages remain in Harness's append-only log and chat transcript. Compaction changes the model's active context, not the original transcript. There is no one-click undo in this version.
• Checkpoints use standard Harness events and continue to work after the plugin is uninstalled.

The context total uses Harness's token meter. Category estimates use its fixed text heuristic and do not necessarily sum to the total. CJK text, tool schemas, image pricing, provider accounting, and framing can differ. The header percentage follows Harness's existing live context projection; it is absent before the model reports enough information. The panel still shows estimates when the context limit is unavailable.

Install a packaged release

dsh plugin --profile tauri add /absolute/path/dsh-context-manager-0.1.5.tgz

Use your actual Harness profile name. The community Linux desktop uses tauri on the tested installation. Other Harness desktop distributions may use desktop; quit that desktop before changing its reserved profile. Restart Harness after updating the plugin: reloading the frontend or toggling a component can leave the previously imported host module cached.

Some community desktop builds incorrectly remove local .tgz installs during startup, treating the archive as a missing directory. On those builds, keep this project in a permanent folder, run npm ci and npm run build there, then install the folder with dsh plugin --profile tauri add /absolute/path/dsh-context-manager. Keep the folder while the plugin is installed. This workaround requires no desktop source changes.

This targets DeepSeek Harness's plugin runtime, not the separate DeepSeek consumer chat app. The host and browser APIs are standard Harness APIs. The tested host is Harness 0.2.0-rc.2 inside the community Linux desktop; another official desktop build must supply the same APIs. No claim of native macOS or Windows desktop testing is made.

Development and validation

Requires Node.js 22.19+ and the matching Harness packages. The plugin has no additional production dependency beyond host-supplied peer packages. Browser React is supplied by Harness. The host entry is bundled into one small module so plugin updates reload its helpers together.

npm ci
npm run check
npm run test:package
npm pack

Tests use Harness's real Session, token meter, compaction invariant companion, AgentLoop, command registry, and JSONL persistence with synthetic history and a controlled model. They cover retained reasoning, balanced tool pairs, selective ranges, read-only preview, cancellation, stale plans, save failures, and replay without the plugin. The package check validates the archive's exact public file list and reruns the host and browser suites against its extracted entries. They do not measure the quality of a real model's summary.

Control commands use Harness's existing authenticated command route. Their records stay outside model context. While installed, the plugin hides inspection/preview payloads from ordinary chat cards and displays a short successful-compaction record. Original control records remain in the session log.

Failure handling

If Rewind or another plugin replaces the active history or changes its request route while a summary is streaming, the preview cancels the obsolete model request. It ignores unrelated sessions and non-context events. The fingerprint is still checked before publishing and applying a preview. Multiple views of the same session keep separate registrations, so closing one view does not disable the remaining view's Context command.

Apply checks persistence before changing context and flushes again afterward. A final disk error is reported as changed in memory, saving failed. A multi-range append failure reports how many ranges were applied. The preview is consumed once committing starts so an uncertain operation is never automatically retried. Refresh and inspect the current session after such an error.

Related plugins and improvement directions

Source review on 2026-10-02 identified useful complementary approaches:

• dsh-auxiliary routes purpose: 'compaction' requests to a separate model. This plugin already marks summary calls that way; its automated tests check the marker and original route. Live interoperability with that router has not been tested.
• Context Compression Selector offers automatic tool-output reduction and model-specific token accounting. Its explicit distinction between tokenizer counts, estimates, and unavailable counts is a useful direction for improving this panel's approximate breakdown. No tokenizer or reducer from that project is bundled here.
• dsh-context-management provides history recall and session notes alongside automatic compaction. Read-only retrieval of original messages would be a useful future addition here; retaining the log does not currently give the model a recall tool.

These three projects have not been tested for live interoperability. This plugin remains a manual, reviewed compaction interface. Automatic policy, precise provider accounting, permanent pins, history recall tools, and undo remain future work.

Installed-plugin compatibility check

The 2026-10-08 check used the real Harness 0.2.0-rc.2 services with Rewind 0.15.0, Better Sidebar 0.24.1, DSH Market 1.66.6, and the companion PDF Reader checkout. It exercised stale-preview rejection after rewind, cancelling a streaming summary on rewind, durable compaction, PDF text/image delivery and independent plugin disposal. Market coverage is its route registration and read-only capabilities endpoint; package installation/update operations and the third-party browser interfaces are not exercised. See VALIDATION.md for the desktop-version boundary.

To repeat against explicit local installations, with Poppler available:

npm run test:installed -- /absolute/runtime/root /absolute/profile/root /absolute/pdf-reader/checkout

The profile must already contain Rewind, Better Sidebar and DSH Market. The script reads their packages and uses Harness's own module-resolution service, then creates scratch sessions, snapshots, attachments and market storage. It does not boot the live profile or read its conversations. Model responses, settings UI, loader inventory and web-runtime metadata are controlled fixtures; session, command, tool, persistence, HTTP routing and plugin code are real. A temporary loopback server is closed on completion. No paid model request or package-manager mutation is made.

Compatibility and resource checks

All selected summary ranges are checked against the transcript limit before the first model request. An oversized later range therefore leaves history unchanged without charging an earlier summary request. Omit-only ranges do not require a model or summary transcript.

CI tests packed host and browser artifacts on Linux, macOS and Windows. The pinned baseline is Harness 0.2.0-rc.2; an additional Linux/Node 24 lane exercises 0.2.1-alpha.1 without changing the release dependency pins. These are plugin/runtime checks, not packaged desktop GUI tests.

Store compatibility and permissions

The manifest includes the Store-specific dsh.compatibility matrix as well as the host's engines.dsh gate. Packed API tests pass on DSH 0.2.0-rc.2, 0.2.1-alpha.1, and 0.2.1-alpha.2. Linux, macOS and Windows packed-plugin tests exercise host and browser contracts, not packaged desktop GUIs. Web/desktop profiles need the stated conversation and command client modules; headless profiles expose only the command.

Capability	Scope
Conversation data	Reads the selected session's active history to estimate usage and build a preview. Recorded reasoning is excluded from summary input and client excerpts.
Persistent changes	After the user reviews and applies a preview, writes standard compaction events through Harness session persistence. Original log entries remain. There is no undo button; Keep is not a permanent pin.
Network and cost	Summary generation uses the configured Harness LLM service and may send selected transcript text to its provider and incur usage charges. Omission-only previews make no model request.
Credentials	Uses the host's configured LLM service; does not request, display, or directly read provider credentials.
Files and processes	No direct filesystem, shell, native executable, package installation, Profile modification, or restart API in shipped runtime code. Session persistence is an indirect disk-write effect handled by Harness.
Dependencies	Host-supplied DSH services and React; no bundled native tools, external server, or production npm dependencies. The committed host bundle installs without prepare or install hooks; prepack is a maintainer packaging step.

Because this plugin changes active conversation context and can invoke a model, it needs a permission-aware review even if a static scanner does not recognize those host-service effects. Listing, automatic source checks, tests, and independent security review are separate states. CLI install/start/uninstall/rollback operation records remain explicitly unknown unless a disposable-profile report establishes them; ordinary host tests do not establish those operations.