dsh-tool-deny

Choose which tools each agent preset gets in DeepSeek Harness (dsh).

A plugin loaded at the root of a profile registers its tools globally, so every preset inherits them. A preset can add plugins, but it has no setting to remove a global tool. dsh-tool-deny fills that gap with a few lines of YAML.

Features

Option	Where	Value	What it does
hideByPreset	Root row	Map of preset id to tool names	Removes tools from the model's tool list for the presets you name
hide	Inside a preset	Tool names	Same, for the preset that mounts the plugin
deny	Inside a preset	Tool names	Keeps tools listed, but refuses every call
hideSections	Either	Section names	Blanks global system prompt sections for those agents

Use hideByPreset in a root row, and hide and deny in a preset row. If a row sets hideByPreset, hide and deny are ignored and a warning is logged.

Hidden tools cost no tokens, because their definitions are never sent to the model. Other presets are unaffected. Subagents, automation runs and resumed sessions are covered too.

Requirements

Tested on dsh 0.2.1-rc.4.

Install

dsh plugin --profile web add dsh-tool-deny

The plugin does nothing until you configure it.

Quick start

Say you installed a plugin that adds image_search and translate, and you want to keep them away from your minimal and reviewer presets. Add this to your profile's cordis.patch.yml:

- insert:
    - id: tool-deny-root
      name: dsh-tool-deny
      config:
        hideByPreset:
          minimal:
            - image_search
            - translate
          reviewer:
            - translate

Restart dsh. New minimal sessions no longer see either tool, reviewer sessions no longer see translate, and every other preset keeps both.

If several presets share a list, a YAML anchor avoids repeating it:

hideByPreset:
  minimal: &extra-tools
    - image_search
    - translate
  reviewer: *extra-tools

Use inside a preset

Use this when a preset should carry its own rules, or when you need deny. Add the row to the preset's plugins list:

- id: tool-deny
  name: dsh-tool-deny
  config:
    hide:
      - image_search
    deny:
      - delete_records

image_search disappears from the list. delete_records stays listed, and calling it returns "delete_records" is not available to this agent.

Hide or refuse?

Prefer hiding: the model never sees the tool, and you save its tokens. Use deny for tools that hiding can't reach, which are the ones a plugin registers on each agent directly (through agent.ctx) instead of globally. If you try to hide one, it stays visible.

Hide prompt sections

Some plugins add a global section to the system prompt. Blank it by name for the same agents:

config:
  hideByPreset:
    minimal:
      - image_search
  hideSections:
    - my-plugin:notes

At the root, hideSections applies to every preset named in hideByPreset. The section name is defined by the plugin that registers it.

Limitations

• Failures are quiet. If you remove the row or the plugin stops loading, the tools come back with no error. Don't rely on it as your only safeguard for a sensitive agent.
• Lists are by name. A new tool added by a plugin update stays visible until you add it.
• Unknown names are skipped. A tool name that doesn't exist logs a warning and is otherwise ignored, so check your spelling.
• It hides tools, not plugins. The plugin keeps running. Anything it does beyond its tools, such as acting as the provider behind web_search, is unchanged.
• Preset switches can drop tools. Switching a new session to another preset and back can leave out subagent, which is dsh behavior. Starting a fresh session restores it.

How it works

In root mode, the plugin listens for agent/created and agent-preset/selected, looks up the agent's preset, and calls ctx.tools.restrict({ deny }) on that agent. dsh then filters those tools whenever it builds the agent's tool list. The tools stay registered, so other agents are unaffected. deny uses ctx.tools.guard, which rejects the call at execution time.

License

MIT