slice

A planning guide for defining the smallest complete piece of a software change. A vertical slice works through all the layers needed to show useful behavior from start to finish.

In plain words
What is it for?
Use it before implementation planning to choose a small, demonstrable first feature and break the work into independently testable steps.
Why use it?
It prevents plans from becoming large batches of unfinished work, such as building every database model before any user-visible result exists.

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/luisalima/agent-policy-kit/slice
Any agent
npx skills add luisalima/agent-policy-kit --skill slice
Clone the repo
git clone --depth 1 https://github.com/luisalima/agent-policy-kit

Made for: Claude Code, Codex.

Per session 15 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 109 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 $0.00015 $0.00109
Opus 5 $0.00008 $0.00055
Sonnet 5 $0.00003 $0.00022
Haiku 4.5 $0.00002 $0.00011

Measured yesterday against content hash 3e5f67fa4a3e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

slice 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.

.agents/skills/slice/SKILL.md · 17 lines

What it actually says

Vertical Slice

Before planning implementation, define the smallest vertical slice:

  • What can a user or caller do after this slice that they could not before?
  • Does it touch every layer needed to be demonstrable end-to-end?
  • Is there a smaller slice that still delivers observable value?

Each step in the plan should be demonstrable on its own.

Avoid horizontal plans such as all models first, then all controllers, then all UI.

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. yesterday First seen · 17 lines · 15 tokens per session scan A 3e5f67fa4a3e

Subscribe to this mod's changes

slice is a skill published in the GitHub repository luisalima/agent-policy-kit (2 stars, last pushed 2mo ago), licensed MIT. It adds 15 tokens to every session and 109 once invoked, about $0.0001 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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