dsh-inject-head

Inject a fixed block of text at the very top of every DeepSeek Harness system prompt — including presets that normally discard outside contributions.

Zero dependencies. One file to edit. Takes effect on the next turn, no restart.

your text                                  ← line 1, this plugin
You are an AI agent that helps the user…   ← harness identity
…deployment persona, tools, policies…

---

Why this needs two mechanisms

DSH assembles a prompt by sorting sections ascending on (order, name) and joining the non-empty ones with blank lines. A section at order -5000 therefore lands above harness:identity (-1000) and the deployment persona (0):

Section	Order
operator:head ← this plugin	-5000
harness:identity	-1000
deployment:persona-prefix	0
tools / policies	1000 … 9900
deployment:persona-suffix	10200

But a preset declared complete: true (for example minimal) runs sections: [ownPersona] at the end of assembly and throws every other section away. No section can reach it — that is host behaviour, not a limitation of this plugin.

So the plugin registers two things from the same text source:

1. the global section operator:head at order -5000, with interpolate: false so braces and {{…}} in your own words can never break an assembly;
2. the prompt variable inject_head.

Section-based presets get the text for free. For a complete: true preset, add one line to that preset's persona prefix:

prefix: >-
  {{inject_head}}

  You are a helpful software engineer assistant.

The same file still drives the text. Nothing else about the preset changes.

Install

The package declares dsh.bundle.patch, so it installs as a normal bundle.

git clone https://github.com/HYBB-rash/dsh-inject-head.git

Then point the plugin manager at the cloned directory — install_bundle with its absolute path — or add it to ~/.dsh/profiles/<profile>/package.json by hand:

{
  "dependencies": {
    "dsh-inject-head": "link:/absolute/path/to/dsh-inject-head"
  },
  "dsh": {
    "profile": {
      "bundles": ["…", "dsh-inject-head"]
    }
  }
}

Link the package into the profile's node_modules, then restart the harness once. Editing the text afterwards never needs a restart.

Configure

One text source, four levels, highest priority first:

Priority	Source	Notes
1	DSH_INJECT_HEAD_TEXT	inline; trimmed
2	DSH_INJECT_HEAD_FILE	path to a UTF-8 file; trimmed
3	$DSH_HOME/inject-head.md	default path (~/.dsh/inject-head.md)
4	DEFAULT_TEXT in index.mjs	'' — inject nothing

mkdir -p ~/.dsh
printf 'Answer in English. Prefer short answers.\n' > ~/.dsh/inject-head.md

• edit the file → next assembly picks it up (cached on mtime)
• empty the file → injection silently stops
• delete the file → nothing is injected

Use the environment variables when you want the text to travel with the shell rather than with the home directory — useful for per-project overrides.

Verify

Ask the harness to dump the composed prompt, or check the first line of any session:

dsh --profile "$DSH_PROFILE" --dump-config

The plugin row appears as inject-head with name pointing at index.mjs. To check the assembled prompt instead, ask your agent "what is the first line of your system prompt?" — it should be your text verbatim.

Run the plugin's own tests:

npm test    # 9/9 passed

Limits

• complete: true presets need the one-line persona edit. The plugin cannot inject a section into them; only the variable route works.
• Don't edit a preset persona that another plugin asserts on. Some plugins validate a preset's persona by exact string equality and silently disable themselves when it changes. Adding {{inject_head}} to such a preset will trip that check — use a different preset, or leave that one uncovered.
• The text enters session history. It is part of the system prompt, so it shows up in exported or shared sessions. Never put secrets in it.
• It costs tokens every turn. A short line is negligible; a paragraph is not.

中文说明

在每份系统提示词的最上方注入一段固定文本。

• 唯一真源是 ~/.dsh/inject-head.md，改完下一轮即生效，不用重启
• 清空文件即关闭注入，删除文件则什么都不注入
• 也可用 DSH_INJECT_HEAD_TEXT（直接给文本）或 DSH_INJECT_HEAD_FILE（指定文件）覆盖

覆盖范围：普通 preset（standard / ptc / cordis 这类按 section 组装的）自动生效；声明了 complete: true 的 preset（如 minimal）在组装末尾会丢弃所有其它 section，需要你在它的 persona 前缀里加一行 {{inject_head}}，文本仍由同一个文件驱动。

已知边界：若某个 preset 的 persona 被其它插件按精确字符串校验，改它会让那个插件静默失效 —— 这种情况请换一个 preset，或让它保持不覆盖。注入内容会进入会话历史，导出或分享会话时可见，不要放密钥。

License

MIT © 2026 Herman Hong