DeepSeek Harness v0.1.7-alpha.1: Session V4 & Messages API

DeepSeek released dsh-v0.1.7-alpha.1 on September 22, 2026. This pre-release changes several foundations at once: Session storage moves to V4, the official DeepSeek adapter becomes Messages-API-only, Agent Presets move into plugin Bundles, and Profile settings are managed through plugin configuration.

Users get session archiving, background work, richer file review, Office previews, and dedicated settings surfaces. Teams that maintain plugins, private model endpoints, or shared Profiles have a larger migration to plan.

Release and npm channels

Pin alpha.1 for a reproducible run:

npx @deepseek-ai/[email protected] web

Running npx @deepseek-ai/dsh without a version still follows latest; it does not opt into the 0.1.7 alpha line.

Sessions become an operational workspace

The sidebar can now pin, archive, filter, undo, and restore Sessions. Archiving an active Session first lists the affected turns, Sub-agents, jobs, and reminders, then presents a stop-and-archive confirmation.

Long commands and workflows can continue in the background with live output. First launch creates a default workspace and blank Session, shortening the path to the first task.

Other visible changes include:

• faster long-conversation loading and turn navigation;
• file refresh, open, reveal, and side-by-side diffs;
• collapsible process groups;
• dedicated Work Details, Performance & Usage, and Developer Tools settings;
• XLSX, XLS, CSV, and TSV previews;
• zoom controls for PDF, Office, and image previews.

The Session list is therefore becoming the entry point for task state, processes, files, and usage—not only a chat-history menu.

Session V4: migrate, then test recovery

Alpha.1 introduces Session Log V4 and a batch migration tool. Partial V3 compatibility remains, but long-lived Profiles should not rely on compatibility behavior as their migration plan.

Back up Sessions and Profiles, then validate at least four paths:

1. open a long historical Session and inspect messages, attachments, and tool calls;
2. continue that Session through a model call and file write;
3. restart DSH and verify jobs, archive state, and titles;
4. export or copy a critical Session and confirm existing team tools can read V4 logs.

Attachments that exist only inside custom events are no longer read and exported automatically. Plugins that depend on that behavior must handle those attachments explicitly.

The official DeepSeek adapter is Messages-API-only

The official DeepSeek adapter removes the Chat Completions path and the protocol setting. Existing configuration should remove protocol and point to a Messages-compatible endpoint.

Do not stop testing at “Provider connected.” Create a fresh Session and cover:

• plain text responses;
• Tool Call and Tool Result round trips;
• image or file content blocks;
• long context and proactive compaction;
• interruption and continuation.

Proactive compaction now reserves output and context headroom, reducing cases where compaction happens too late for the current turn to finish.

Agent Presets move into plugin Bundles

Agent Presets are now declared and installed by plugin Bundles. Presets stored in legacy directories need migration; teams should not assume those directories will continue to be scanned.

This unifies Agent composition with the plugin system. Bundles can carry multiple patch files, localized titles and descriptions, icons, and live-update fields. Creator-mode guidance is loaded on demand to avoid occupying context when unused.

--dump-config-schema can export the active configuration schema for before-and-after comparisons.

Agent Teams, task boards, and built-in modes

Agent Team tools now use member names. The task board is read-only, while Agents update tasks through tools. Built-in Agent modes gain purpose statements, guidance, and example tasks.

Plugins that wrote directly into task-board UI state need to call the supported tools. Team automation should also treat stable member names—not display order or temporary IDs—as identity.

Windows deletion-boundary fix

Alpha.1 fixes a Windows sandbox issue in which deletion could escape an authorized directory and cross workspace boundaries. Windows users and shared-workspace operators should prioritize this update and rerun deletion-boundary tests.

Test deletion inside the workspace, attempted access to a neighboring workspace, relative and absolute paths, paths with spaces, and denial behavior.

Remote transport and plugin changes

Bidirectional remote streaming gains binary transport, with readers migrating toward readBytes. Plugins can publish localized metadata and multi-patch Bundles. Browser tools default off on Web and on in Electron, so Profiles should no longer assume the same default across both environments.

Other fixes cover reverse-proxy subpaths, legacy Sub-agent notification Sessions, plugin-install connection state, local Markdown images, Files API errors, Playwright blocking new Agents, and large streaming tool arguments blocking the process.

Upgrade checklist

Alpha.1 is broader than a routine patch. Stable production Profiles can stay pinned to an rc release; teams evaluating Session V4, Messages API, or plugin-based Presets should test 0.1.7-alpha.1 against a copied Profile.

Related reading

• DeepSeek Harness v0.1.7-alpha.2 update
• DeepSeek Harness v0.1.6-alpha.2 update
• DeepSeek Harness Plugin Manager
• DeepSeek Harness security guide

FAQ

Is v0.1.7-alpha.1 the npm default?

No. The exact version is published, but latest remains 0.1.5-rc.2. Pin the full version to reproduce alpha.1.

Can an older DeepSeek Provider configuration be reused unchanged?

Inspect it first. The official adapter removes protocol and the Chat Completions route, so the endpoint must support Messages API.

Will a legacy Preset directory continue to load automatically?

The new architecture declares and installs Agent Presets through plugin Bundles. Migrate directory-based Presets to that structure.