working-on-plugins

working-on-plugins is a skill for Claude Code from joshsymonds/savecraft.gg. It costs 73 tokens per session (1,596 once invoked), scanned A, original, Apache-2.0.

A set of design rules for Savecraft plugins and adapters that turn game data into structured information for AI assistants.

In plain words
What is it for?
Use it when creating game plugins, adding or changing save-data sections, or designing the output produced by parsers and web API adapters.
Why use it?
It helps keep each game save easy to understand, starting with a useful summary and then providing detailed sections when needed.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

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/joshsymonds/savecraft.gg/working-on-plugins
Any agent
npx skills add joshsymonds/savecraft.gg --skill working-on-plugins
Clone the repo
git clone --depth 1 https://github.com/joshsymonds/savecraft.gg

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for working-on-plugins

README.md
[![agentmods](https://agentmods.dev/badge/skills/joshsymonds/savecraft.gg/working-on-plugins.svg)](https://agentmods.dev/skills/joshsymonds/savecraft.gg/working-on-plugins)
Your own site
<a href="https://agentmods.dev/skills/joshsymonds/savecraft.gg/working-on-plugins"><img src="https://agentmods.dev/badge/skills/joshsymonds/savecraft.gg/working-on-plugins.svg" alt="Measured on agentmods" height="20"></a>
Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,596 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 5.1 $0.00073 $0.01596
Opus 5 $0.00036 $0.00798
Sonnet 5 $0.00015 $0.00319
Haiku 4.5 $0.00007 $0.00160

Measured 6d ago against content hash bf705c236edc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

working-on-plugins scanned grade A with 0 findings 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 6d ago.

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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/working-on-plugins/SKILL.md · 139 lines

How it starts

The opening of the file, as written. The whole thing — 139 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Working on Plugins: Section Design

Both WASM plugins (plugins/*/parser/) and API adapters (worker/src/adapters/) produce the same GameState shape: identity, summary, and sections. This skill covers how to design sections so they work well with the MCP tools and AI consumers.

For the ndjson contract, WASM runtime, and plugin build system, see docs/plugins.md. For API adapter architecture, see docs/adapters.md.

Overview Section (Required)

get_save embeds one section's data as the overview in its response. It picks the first match from this list:

character_overview → player_summary → overview → summary

Every plugin MUST produce a section matching one of these names. If none match, get_save falls back to the first section alphabetically — which may be a 200KB deck list or item dump.

The overview section is the AI's first look at the save. It should contain enough context to answer "what is this character/save?" and guide the AI to the right detailed sections.

What belongs in the overview

  • Identity: name, class, level, rank — whatever defines "who"
  • Key stats: currency, progression milestones, win/loss record
  • Index of available sections with pointers — deck names (not card lists), character names (not inventories), match list (not turn-by-turn logs)
  • Anything that helps the AI decide which section to fetch next

What does NOT belong in the overview

  • Full item lists, card lists, or inventories
  • Turn-by-turn logs, match replays, or event histories
  • Large nested objects that the AI won't use to route

Target: overview section < 15KB. A typical overview is 2-10KB.

Section Size Limits

Limit Value Enforced by
Hard max per section 80KB SECTION_SIZE_LIMIT in worker/src/mcp/tools.tsget_section rejects sections over this
Overview target < 15KB Convention — keeps get_save response usable
Individual item section < 10KB typical Convention — per-deck, per-character sections

Read the full file on GitHub · 139 lines

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. 6d ago First seen · 139 lines · 73 tokens per session scan A bf705c236edc

Subscribe to this mod's changes

working-on-plugins is a skill published in the GitHub repository joshsymonds/savecraft.gg (12 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 73 tokens to every session and 1,596 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other skills, from other repositories

gameobject-component-destroy

Destroy one or more Components from a target GameObject. Missing (null) components are skipped — they cannot be destroyed. Use 'gameobject-find' and 'gameobject-component-get' to identify the components first.

IvanMurzak/Unity-MCP · 49 tokens

unity-version-split

Split a C# file into Unity 6.5+ and pre-Unity 6.5 variants. Use when a file needs different implementations for different Unity versions due to API changes (e.g., EntityId vs int, GetEntityId vs GetInstanceID).

IvanMurzak/Unity-MCP · 59 tokens

playtest-report

Generates a structured playtest report template or analyzes existing playtest notes into a structured format. Use this to standardize playtest feedback collection and analysis.

Donchitos/Claude-Code-Game-Studios · 35 tokens

unity-manual-component

Manually add, configure, reorder, and copy components on GameObjects using Unity Editor UI. For one-off Inspector workflows that do not need REST automation.

Besty0728/Unity-Skills · 36 tokens

godot-signals-groups

Build event-driven, decoupled Godot 4.7 gameplay with signals and node groups: declare and emit custom signals, connect with Callables (incl. bind/one-shot), and broadcast to many nodes via groups and callgroup. Use when wiring node communication in a Godot project, replacing tight references with signals…

gamedev-skills/awesome-gamedev-agent-skills · 95 tokens

threejs-exposure-color-grading

Build a measured exposure and grading path in Three.js. Use for a 64x36 encoded luminance meter, asynchronous readback, weighted log-average exposure, asymmetric adaptation, single tone-map ownership, and a generated 32-cube post-tone-map LUT.

scottstts/Threejs-Awesome-Graphics-Agent-Skills · 60 tokens