Cursor Backend Setup

What it does

When your agent uses it

• Making Cursor the default implementation backend for your user account
• Checking whether the Cursor plugin and agent are ready for the Harness
• Setting or removing a project-level Cursor backend override

Example prompts

• “Run cursor:setup --check and tell me whether Cursor is ready.”
• “Make Cursor the default backend for this project only.”
• “Remove my user-level Cursor default and go back to the claude fallback.”

Requirements

• Claude Code Harness plugin with its setup-cursor.sh and set-impl-backend.sh scripts
• Bash
• Pre-approved tools (allowed-tools): Read, Bash

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

1. 1For --check, run
2. 2For --user-default, run
3. 3For --project-default, run
4. 4For --unset, ask whether the target is user or project scope if not clear from the request, then run exactly one matching unset command

What it can do on your machine

Read from SKILL.md and the folder at commit 2b2b748. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Bash

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • bash

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Cursor Backend Setup loads about 1.1k tokens when it runs. Until then it costs about 81 tokens; SKILL.md has 160 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~81

When it runs · the whole SKILL.md, loaded when a task matches

~1.1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• NotePre-approves every shell command (allowed-tools: Bash)SKILL.md

  allowed-tools: Read, Bash

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from Chachamaru127/claude-code-harness at commit 2b2b748, republished under its MIT licence (© Chachamaru127). 160 words, ~1,141 tokens.

name

cursor-setup

description

Configure and verify the Cursor backend for Claude Code Harness. Use when user invokes cursor:setup, wants Cursor as the local default implementation backend, or asks to check Cursor plugin/agent readiness. Distribution default remains opt-in; only local env/user settings are changed when explicitly requested.

allowed-tools

Read, Bash

description-en

Configure and verify the Cursor backend for Claude Code Harness. Use when user invokes cursor:setup, wants Cursor as the local default implementation backend…

description-ja

Claude Code Harness の Cursor backend を設定・検証するスキル。cursor:setup、Cursor を現環境の default 実装 backend にしたい、Cursor plugin/agent readiness を確認したい時に使う。配布 plugin の…

argument-hint

[--check | --user-default | --project-default | --unset]

user-invocable

true

cursor:setup --check
cursor:setup --user-default
cursor:setup --project-default
cursor:setup --unset

HARNESS_PLUGIN_ROOT="${HARNESS_PLUGIN_ROOT:-${CLAUDE_PLUGIN_ROOT:-}}"
if [ -z "$HARNESS_PLUGIN_ROOT" ] && [ -n "${CLAUDE_SKILL_DIR:-}" ]; then
  probe="$(cd "${CLAUDE_SKILL_DIR}" && pwd)"
  while [ "$probe" != "/" ] && [ ! -d "$probe/scripts" ]; do
    probe="$(cd "$probe/.." && pwd)"
  done
  [ -d "$probe/scripts" ] && HARNESS_PLUGIN_ROOT="$probe"
fi
if [ -z "$HARNESS_PLUGIN_ROOT" ]; then
  echo "ERROR: HARNESS_PLUGIN_ROOT is not set and could not be derived from CLAUDE_PLUGIN_ROOT or CLAUDE_SKILL_DIR" >&2
  exit 2
fi

© Chachamaru127, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in skills/cursor-setup of Chachamaru127/claude-code-harness.

Open the folder on GitHubat commit 2b2b748