Bites the DSH: Read-Only Playback of Native DeepSeek Harness Sessions

Preface¶

The core philosophy of DeepSeek Harness (DSH) is “everything is a plugin”. When developing agents or debugging session logic, we often need to review the execution process of historical conversations, not merely inspect the text. Existing approaches often require switching between multiple windows or tabs, or relying solely on manual scrolling to locate state changes.

The bites-the-dsh plugin offers a more direct solution: it transforms the native conversation view in the DeepSeek Harness WebUI into a replayable timeline. This means you can replay historical interactions like playing a video without leaving the current session interface or opening an external panel.

Plugin Overview¶

Bites the DSH is a read-only, script-controllable session replay plugin designed for the DeepSeek Harness WebUI.

Maintainer: memorax-ai
License: MIT
Core value: Provides historical replay capability within the native DSH interface while preserving the integrity of the session source.

It modifies DSH’s Conversation and Chat services through the Harmony patch mechanism, enabling the session header control bar to launch replay mode directly.

Core Features¶

The plugin transforms the native conversation view into a replay view, primarily including the following capabilities:

Native integration and entry point: It uses the native DSH session header control bar as the entry point, without opening a standalone panel. During replay, the native editor, model calls, stop, branch, and assistant-writing operations are disabled, ensuring the view remains read-only.
Playback controls: Provides complete playback controls, including pause, fast forward, reverse playback, and single-step execution (event-based jumping). Supports adjusting playback speed and idle gap compression to optimize the replay experience.
Direct jumps: Supports direct jumps by event, by turn, or by timestamp.
Simulated typing preview: In read-only mode, the native editor simulates displaying the next direct user message, without modifying the actual draft.
Script control API: The plugin exposes the ctx.sessionPlayback controller, allowing other plugins or scripts to control the playback state via code.
Historical projection: Projects history through DSH’s native ChatView, allowing the source session and the current “replay pointer” to run independently without interfering with each other.

Installation and Enabling¶

Run the following commands in the terminal to install the plugin:

dsh plugin --profile web add @ch4acko3/bites-the-dsh
dsh harmony status --profile web

After installation, ensure all patch statuses are bound. Then reload the DeepSeek Harness WebUI, open any session, and click Replay session in the session header control bar to enter replay mode.

Typical Usage: Script Control¶

In addition to manual controls, the ctx.sessionPlayback service provided by the plugin allows other plugins or scripts to automate the replay workflow.

The following is an example of controlling playback with TypeScript:

const playback = ctx.sessionPlayback

// 进入指定会话的回放模式
playback.enter(sessionId)

// 跳转到特定时间点（Unix epoch 毫秒）
playback.seekTime(sessionId, Date.parse('2026-08-20T12:00:00Z'))

// 设置播放速度并开始播放
playback.play(sessionId, 1)

// 暂停回放
playback.pause(sessionId)

// 退出回放模式
playback.exit(sessionId)

This service also supports event/turn jumps, reverse playback, rate and idle gap settings, subscriptions, and position reading. It intentionally does not expose any operations that modify the source session, ensuring that the replay process is purely visual.

Use Cases and Notes¶

Use cases: Debugging agent behavior at a specific point in time, demonstrating historical conversation flows to non-technical users, and analyzing the historical transition logic of session state machines.
Read-only constraints: During replay, the native editor and session switching operations are blocked. The plugin modifies only view presentation and has no side effects on source session data.
Permissions and security: As a DSH plugin, it runs with the permissions of the Harness process. It is advisable to review its source code and license before installation.

Summary¶

Bites the DSH aligns with the DSH Harmony ecosystem and provides developers with a lightweight session replay tool. Through seamless integration with the native UI and a strict read-only design, it addresses the pain point of reviewing historical sessions. Combined with its scripting API, it can serve as part of more complex workflows.