plugin-settings

A per-project settings pattern for plugins, using a local Markdown file with YAML settings at the top and notes or instructions below.

In plain words
What is it for?
Use it to store options, limits, modes, session details, and extra instructions that plugin commands, hooks, or agents can read.
Why use it?
It keeps user-specific configuration and plugin state outside the main plugin files and out of version control.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/ronmkr/promptbook/plugin-settings
Any agent
npx skills add ronmkr/PromptBook --skill plugin-settings
Clone the repo
git clone --depth 1 https://github.com/ronmkr/PromptBook

Made for: Claude Code, Codex.

Per session 83 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,127 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00083 $0.03127
Opus 5 $0.00042 $0.01563
Sonnet 5 $0.00017 $0.00625
Haiku 4.5 $0.00008 $0.00313

Measured 2d ago against content hash 5688fbe3bab2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

plugin-settings scanned grade B with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (examples/read-settings-hook.sh, scripts/parse-frontmatter.sh, scripts/validate-settings.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

- Readable by user only (`chmod 600`)
core/plugin-dev-toolkit/skills/plugin-settings/SKILL.md · 545 lines

How it starts

The opening of the file, as written. The whole thing — 545 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Plugin Settings Pattern for Antigravity Plugins

Overview

Plugins can store user-configurable settings and state in .geminiplatform-install-name.local.md files within the project directory. This pattern uses YAML frontmatter for structured configuration and markdown content for prompts or additional context.

Key characteristics:

  • File location: .geminiplatform-install-name.local.md in project root
  • Structure: YAML frontmatter + markdown body
  • Purpose: Per-project plugin configuration and state
  • Usage: Read from hooks, commands, and agents
  • Lifecycle: User-managed (not in git, should be in .gitignore)

File Structure

Basic Template

---
enabled: true
setting1: value1
setting2: value2
numeric_setting: 42
list_setting: ["item1", "item2"]
---

# Additional Context

This markdown body can contain:
- Task descriptions
- Additional instructions
- Prompts to feed back to Gemini
- Documentation or notes

Example: Plugin State File

.gemini/my-plugin.local.md:

---
enabled: true
strict_mode: false
max_retries: 3
notification_level: info
coordinator_session: team-leader
---

# Plugin Configuration

This plugin is configured for standard validation mode.
Contact @team-lead with questions.

Reading Settings Files

From Hooks (Bash Scripts)

Pattern: Check existence and parse frontmatter

#!/bin/bash
set -euo pipefail

# Define state file path
STATE_FILE=".gemini/my-plugin.local.md"

# Quick exit if file doesn't exist
if [[ ! -f "$STATE_FILE" ]]; then
  exit 0  # Plugin not configured, skip
fi

# Parse YAML frontmatter (between --- markers)
FRONTMATTER=$(sed -n '/^---$/,/^---$/{ /^---$/d; p; }' "$STATE_FILE")

# Extract individual fields
ENABLED=$(echo "$FRONTMATTER" | grep '^enabled:' | sed 's/enabled: *//' | sed 's/^"\(.*\)"$/\1/')
STRICT_MODE=$(echo "$FRONTMATTER" | grep '^strict_mode:' | sed 's/strict_mode: *//' | sed 's/^"\(.*\)"$/\1/')

# Check if enabled
if [[ "$ENABLED" != "true" ]]; then
  exit 0  # Disabled
fi

# Use configuration in hook logic
if [[ "$STRICT_MODE" == "true" ]]; then
  # Apply strict validation
  # ...
fi

Read the full file on GitHub · 545 lines

Files

What ships with it

7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 545 lines · 83 tokens per session scan B 5688fbe3bab2

Subscribe to this mod's changes

plugin-settings is a skill published in the GitHub repository ronmkr/PromptBook (2 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 83 tokens to every session and 3,127 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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