A repository survey and research skill that combines local project information with dated, cited internet findings in a briefing file. External grounding means checking current information beyond the codebase.

Use it to inspect manifests, project instructions, documentation, and git activity, then create or refresh a seven-day briefing in docs/ground/.

It reduces generic advice by using the repository's actual technology and recent history to focus the research.

ground — Skill for Claude Code by ondrej-svec/heart-of-gold-toolkit

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.

Any agent

npx skills add ondrej-svec/heart-of-gold-toolkit --skill ground

Clone the repo

git clone --depth 1 https://github.com/ondrej-svec/heart-of-gold-toolkit

Made for: Claude Code.

Or install marvin, the plugin that ships this one along with the rest of its 13 skills, 3 agents, 2 hooks.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/ondrej-svec/heart-of-gold-toolkit/ground/github.svg)](https://agentmods.dev/skills/ondrej-svec/heart-of-gold-toolkit/ground)

Your own site

<a href="https://agentmods.dev/skills/ondrej-svec/heart-of-gold-toolkit/ground"><img src="https://agentmods.dev/badge/skills/ondrej-svec/heart-of-gold-toolkit/ground/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/ondrej-svec/heart-of-gold-toolkit/ground"><img src="https://agentmods.dev/badge/skills/ondrej-svec/heart-of-gold-toolkit/ground.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 116 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,226 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector pass 7 Sept 2026

How audits are shown

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.

Model	Per session	Once invoked
Fable 5.1	$0.00116	$0.03226
Opus 5.5	$0.00046	$0.01290
Sonnet 5.5	$0.00023	$0.00645
Haiku 4.5	$0.00012	$0.00323

Measured 2mo ago against content hash c6d9bf58f2d5, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

ground 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 2mo 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.

plugins/marvin/skills/ground/SKILL.md · 235 lines

How it starts

The opening of the file, as written. The whole thing — 235 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Ground

Survey the current repo, then ground externally on what's relevant. Dynamic per-repo — no static config, no curated tech list. The repo IS the configuration.

Boundaries

This skill MAY: read manifests, scan git history, fetch from the web (WebSearch/WebFetch/context7/gh), write the briefing file at docs/ground/<fingerprint>.md. This skill MAY NOT: edit code, modify configuration, install dependencies, run anything other than read-only gh queries. Briefings are advisory artifacts.

Designed to run as a subagent. Web research bloats context fast — keep the heavy fetching in an isolated context and return only the synthesized briefing to the caller.

Common Rationalizations

Shortcut	Why It Fails	The Cost
"Skip the local survey — just web search for the topic"	The repo's stack disambiguates the search. Without it, results are generic.	Wallpaper briefings that don't change Claude's behavior
"Fetch everything in parallel, ignore timeouts"	One slow source blocks the briefing. Worse: stalls the calling skill.	/work latency balloons; Ondrej learns to skip /ground
"Synthesize without citing sources"	Looks confident, can't be verified, indistinguishable from training-data regurgitation	Defeats the entire point — briefings must be fact-checkable
"Always refresh — never trust the cache"	Re-fetches every time, makes cross-session reuse impossible	Token/time cost on every invocation; cache pattern wasted
"Generate a long briefing — more detail is better"	Past 1500 tokens the briefing gets ignored as wallpaper	Token waste + behavioral degradation

Phase 0: Detect Inputs

Entry: Skill invoked standalone (slash command or Task call from another skill).

Resolve:

cwd — current working directory. From the invocation context.
topic — what the user (or calling skill) is grounding for. From the invocation arguments. Required; if absent, ask via AskUserQuestion.
local_only — boolean flag. Default false. When true, skip Phase 4 (external grounding).
force_refresh — boolean flag. Default false. When true, skip cache check in Phase 3.
invocation_mode — standalone if a user invoked /ground directly (slash command); embedded if another skill or agent handed you this protocol via a Task/subagent call.

Read the full file on GitHub · 235 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.

2mo ago First seen · 235 lines · 116 tokens per session scan A c6d9bf58f2d5

Subscribe to this mod's changes

ground is a skill published in the GitHub repository ondrej-svec/heart-of-gold-toolkit (19 stars, last pushed 1mo ago), licensed MIT. It adds 116 tokens to every session and 3,226 once invoked, about $0.0005 per session on Opus 5.5. 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.

Research

ground next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
groundondrej-svec/heart-of-gold-toolkit	Skill	19	1mo ago	MIT	A	116	Claude Code
imagegenopenai/codex	Skill	134k	today	Apache-2.0	A	113	Codex
playwright-climicrosoft/playwright	Skill	99k	today	Apache-2.0	A	19	Claude Code
local-ai-agentsmicrosoft/ai-agents-for-beginners	Skill	79k	today	MIT	A	200	Claude Code, Codex
systematic-debuggingobra/superpowers	Skill	314k	3d ago	MIT	A	21	Claude Code
next-cache-components-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	95	Claude Code
next-partial-prefetching-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	103	Claude Code