What is system-spec-kit?

A workflow for organizing development work in numbered specification folders that preserve requirements, plans, tasks, decisions, and implementation notes.

Use it to document features or coordinated phases, validate the work, and preserve enough context for later sessions.

It keeps the context of a coding task together across conversations and helps ensure required documentation is created before file changes.

system-spec-kit — Skill for Claude Code and OpenCode by MichelKerkmees

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 MichelKerkmeester/skilled-agent-harness_spec-driven-loops --skill system-spec-kit

Clone the repo

git clone --depth 1 https://github.com/MichelKerkmeester/skilled-agent-harness_spec-driven-loops

Made for: Claude Code, OpenCode.

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/michelkerkmeester/skilled-agent-harness_spec-driven-loops/system-spec-kit/github.svg)](https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/system-spec-kit)

Your own site

<a href="https://agentmods.dev/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/system-spec-kit"><img src="https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/system-spec-kit/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/michelkerkmeester/skilled-agent-harness_spec-driven-loops/system-spec-kit"><img src="https://agentmods.dev/badge/skills/michelkerkmeester/skilled-agent-harness_spec-driven-loops/system-spec-kit.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 32 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 9,787 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 warn 7 Sept 2026

SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

medium Prompt Injection · line 69
Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.

Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be

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	$0.00032	$0.09787
Opus 5	$0.00016	$0.04894
Sonnet 5	$0.00006	$0.01957
Haiku 4.5	$0.00003	$0.00979

Measured yesterday against content hash d1fc34c45870, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

system-spec-kit 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 yesterday.

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.

.opencode/skills/system-spec-kit/SKILL.md · 584 lines

How it starts

The opening of the file, as written. The whole thing — 584 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spec Kit - Mandatory Conversation Documentation

Orchestrates mandatory spec folder creation for all conversations involving file modifications. Ensures proper documentation level selection (1-3+), template usage, and context preservation through AGENTS.md-enforced workflows.

1. WHEN TO USE

What is a Spec Folder?

A spec folder is a numbered directory (e.g., 007-auth-feature/) that contains documentation for a single feature/task or a coordinated packet of related phase work:

Spec folders may also be nested as coordination-root packets with direct-child phase folders (e.g., specs/02--track/022-feature/011-phase/002-child/).

Purpose: Track specifications, plans, tasks, and decisions for one unit of work
Location: Under specs/ using either ###-short-name/ at the root or nested packet paths for phased coordination
Contents: Markdown files (spec.md, plan.md, tasks.md, and implementation-summary.md when work is complete) plus optional support folders such as scratch/, research/, or review/

Think of it as a "project folder" for AI-assisted development - it keeps context organized and enables session continuity.

Activation Triggers

MANDATORY for ALL file modifications:

Code files: JS, TS, Python, CSS, HTML
Documentation: Markdown, README, guides
Configuration: JSON, YAML, TOML, env templates
Templates, knowledge base, build/tooling files

Request patterns that trigger activation:

"Add/implement/create [feature]"
"Fix/update/refactor [code]"
"Modify/change [configuration]"
Positive keywords include add, implement, fix, update, create, modify, rename, delete and configure. The authoritative Gate 3 classifier intentionally omits analyze, decompose and phase from positive triggers; analyze is a read-only disqualifier unless a real write, memory-save or resume trigger is also present.

Read the full file on GitHub · 584 lines

Files

What ships with it

60 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.

yesterday Changed d1fc34c45870
3d ago Changed · +32 lines ad990c9c8d27
4d ago Changed · +16 lines 8c9c179b921d
6d ago Changed · -3 lines · +3 tokens per session scan C → A 52a40a89321e
8d ago First seen · 539 lines · 29 tokens per session scan C 1d945f93715e

Subscribe to this mod's changes

system-spec-kit is a skill published in the GitHub repository MichelKerkmeester/skilled-agent-harness_spec-driven-loops (35 stars, last pushed yesterday), licensed MIT. It adds 32 tokens to every session and 9,787 once invoked, about $0.0002 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 2026-09-03.

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