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.
npx agentmods add skills/stefan-stepzero/shipkit/shipkit-product-definitionnpx skills add stefan-stepzero/shipkit --skill shipkit-product-definitiongit clone --depth 1 https://github.com/stefan-stepzero/shipkitWrote 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.
[](https://agentmods.dev/skills/stefan-stepzero/shipkit/shipkit-product-definition)<a href="https://agentmods.dev/skills/stefan-stepzero/shipkit/shipkit-product-definition"><img src="https://agentmods.dev/badge/skills/stefan-stepzero/shipkit/shipkit-product-definition.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00043 | $0.04367 |
| Opus 5 | $0.00022 | $0.02184 |
| Sonnet 5 | $0.00009 | $0.00873 |
| Haiku 4.5 | $0.00004 | $0.00437 |
Grade A, and why
shipkit-product-definition 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 5d 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.
How it starts
The opening of the file, as written. The whole thing — 457 lines — stays where its author put it; the contents beside it link to each section on GitHub.
shipkit-product-definition — Product Blueprint
Defines WHAT we build to solve discovered user needs. Reads product-discovery.json (pain points, personas, opportunities) and produces a product blueprint: features, UX patterns, differentiators, and the app's essence — its non-negotiable differentiators and interaction/quality bar captured as testable assertions a later eval can score a build against.
This is the product blueprint — it defines the user-facing solution. The technical approach (mechanisms, design decisions, stack) is handled by /shipkit-engineering-definition. Feature phasing (what to build now vs. later) is handled by /shipkit-product-goals through stage gates.
When to Invoke
User triggers:
- "What should we build?", "Define features", "Product definition"
- "UX patterns", "Differentiators", "What to build"
- "Solution design", "Product blueprint"
Workflow position:
- After
/shipkit-product-discovery(needs discovered user needs) - Before
/shipkit-engineering-definition(engineering designs mechanisms for these features) - Before
/shipkit-product-goals(goals derive criteria from features and mechanisms)
Prerequisites
Required (fail gracefully if missing):
.shipkit/product-discovery.json— who the users are and what they need
Recommended (enrich the proposal):
.shipkit/why.json— project purpose and vision.shipkit/goals/strategic.json— project stage and constraints
Optional (for existing projects):
.shipkit/stack.json— technology constraints (informs feasibility).shipkit/codebase-index.json— what already exists
If product-discovery.json is missing, tell the user: "Run /shipkit-product-discovery first — I need to understand user needs before designing a solution." and stop.
Process
Completion Tracking
After reading context, create tasks:
TaskCreate: "Define features mapped to pain points"TaskCreate: "Define 2-4 UX patterns with rationale"TaskCreate: "Capture essence — 3-5 non-negotiable differentiators as testable assertions"TaskCreate: "Capture the interaction/quality bar as testable assertions"TaskCreate: "Write product-definition.json"
What ships with it
2 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.
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.
- 5d ago First seen · 457 lines · 43 tokens per session scan A 535c859d2f28
shipkit-product-definition is a skill published in the GitHub repository stefan-stepzero/shipkit (1 stars, last pushed 1mo ago), licensed MIT. It adds 43 tokens to every session and 4,367 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 2026-08-31.
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