dsh-second-brain: DeepSeek Harness Second Brain Loader

Introduction¶

Every new session in DeepSeek Harness (DSH) starts from scratch by default, with no cross-session memory. This plugin injects local state into the prompt of every new session by hooking ctx.systemPrompt.context.

Plugin Purpose¶

This is a DeepSeek Harness plugin. It injects a bounded, timestamped brain snapshot (identity + state fingerprint + open items + pointers and boundaries) into every new session. It is read-only, performs zero writes, fails loudly, and has zero dependencies.

Core Features¶

Snapshot injection: Injects a snapshot of the local brain into the prompt context of every new session.
Read-only and zero writes: The plugin only calls readFileSync and does not modify brain files.
Fail loudly: If the block length is less than 300 characters, the plugin refuses to register and prints the reason instead of failing silently.
Zero dependencies: Pure ESM with no dependencies on other packages.
Hard limit: Enforces a maxChars limit (default 1000, packaged patch is 1300) to prevent context window overflow.

Installation¶

The plugin requires a Node.js environment, version 18 or higher.

pnpm add @xianshu/dsh-second-brain

Configuration¶

After installation, the plugin is enabled by default (the default in v0.1.0 was the opposite, which can lead to misuse). The key configuration options are as follows:

Option	Default	Description
`brainRoot`	`~/.dsh/brain` (or `$DEEPSEEK_BRAIN`)	Directory containing the brain file
`maxChars`	1000 (packaged patch is 1300)	Maximum character count for the injected block; minimum is 300
`order`	200	Layer order in the system prompt
`inject`	true	Whether injection is enabled; set to `false` or environment variable `DSH_SB_INJECT=0` to disable it

Usage and Verification¶

After installing and restarting DSH, new sessions will automatically receive the injected content.

Verification steps:
1. Open a new session and ask: what Second Brain information did you get at startup?
2. If the answer is correct, the injection is working.
3. Check the logs. A record like the following should appear:

    [second-brain-xianshu] ✅ 注入已注册：name=xianshu-second-brain order=200 块长=NNN 字符

Notes¶

Snapshot mechanism: The injected content is a snapshot, not real-time state. If the file is modified externally, new sessions will still use the snapshot content (the file takes precedence over the snapshot).
Installation default: In the current version, Installed == ON is the default.
GitHub routing limitations: If installed via a github: route, the system requires git to be available in PATH and able to access github.com.

Ecosystem Context¶

The DeepSeek Harness philosophy is “everything is a plugin.” This plugin is maintained by DiaryOfUranus. You can view the directory page on SkillHub, or view the source code on GitHub.