add-slice

add-slice is a skill for Claude Code from SSWConsulting/SSW.VerticalSliceArchitecture. It costs 125 tokens per session (2,193 once invoked), scanned A, original, MIT.

A scaffolding guide for adding one use case to a .NET project that uses Vertical Slice Architecture, where each use case keeps its related code together. It creates the use case's endpoint or event handler, request, response, validator, summary, tests, and needed grouping files.

In plain words
What is it for?
Use it to add an endpoint, command, query, or event-driven use case, including features such as validation, paging, sorting, route parameters, and loading data through existing specifications.
Why use it?
It avoids manually copying the project structure and helps new code follow the repository's existing patterns and vocabulary. It supports both HTTP requests and domain events, which are messages raised when something happens in the application.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

Good fit Use it to add an endpoint, command, query, or event-driven use case, including features such as validation, paging, sorting, route parameters, and loading data through existing specifications.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sswconsulting/ssw.verticalslicearchitecture/add-slice
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 SSWConsulting/SSW.VerticalSliceArchitecture --skill add-slice
Clone the repo
git clone --depth 1 https://github.com/SSWConsulting/SSW.VerticalSliceArchitecture

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 add-slice

README.md
[![agentmods](https://agentmods.dev/badge/skills/sswconsulting/ssw.verticalslicearchitecture/add-slice/github.svg)](https://agentmods.dev/skills/sswconsulting/ssw.verticalslicearchitecture/add-slice)
Your own site
<a href="https://agentmods.dev/skills/sswconsulting/ssw.verticalslicearchitecture/add-slice"><img src="https://agentmods.dev/badge/skills/sswconsulting/ssw.verticalslicearchitecture/add-slice/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.

agentmods 80×15 button for add-slice

Your own site · 80×15
<a href="https://agentmods.dev/skills/sswconsulting/ssw.verticalslicearchitecture/add-slice"><img src="https://agentmods.dev/badge/skills/sswconsulting/ssw.verticalslicearchitecture/add-slice.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 125 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,193 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00125 $0.02193
Opus 5 $0.00063 $0.01097
Sonnet 5 $0.00025 $0.00439
Haiku 4.5 $0.00013 $0.00219

Measured 9d ago against content hash 12bac3a7535d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

add-slice scanned grade A with 1 finding 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 9d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

Then exercise it for real — a green test suite doesn't prove the route is where you think it is. Boot with `aspire start --isolated` (see the `aspire` skill), wait for the WebApi resource to go healthy, and call the endp
.claude/skills/add-slice/SKILL.md · 95 lines

How it starts

The opening of the file, as written. The whole thing — 95 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Add a Slice

A slice is one use case, owning everything it needs from HTTP surface to persistence, in its own folder. CreateHero is a slice. A Feature is the group of slices over the same aggregate, sharing a route prefix — Heroes is a Feature, and it is not itself a slice. CONTEXT.md at the repo root defines both, along with Group, Endpoint, and the rest of the vocabulary. Use those words, and avoid the ones it lists under Avoid.

This skill adds a slice. It creates the Feature and its Group too, but only when the slice is the first one in that Feature.

Not every slice is HTTP. PowerLevelUpdated is a slice triggered by a domain event rather than a request — the same folder-per-use-case shape, with an event handler in place of an endpoint.

Read the live reference first

  • src/WebApi/Features/Heroes/CreateHero/ — the canonical command slice, all five files
  • src/WebApi/Features/Heroes/GetAllHeroes/ — a paged, sorted list query
  • src/WebApi/Features/Teams/GetTeam/ — a single-item query with a route parameter
  • src/WebApi/Features/Teams/AddHeroToTeam/ — a command that loads aggregates through specs
  • src/WebApi/Features/Teams/PowerLevelUpdated/ — an event-triggered slice

The templates in references/ follow these. If they disagree, the repo wins — follow it and fix the template.

What you need to know before scaffolding

Input Notes
Feature The plural noun that owns the route prefix (Heroes, Teams). Does one already exist for this aggregate, or is this its first slice?
Use case Verb + noun, PascalCase (CreateHero, ArchiveTeam). This names the slice folder, the endpoint, and the OpenAPI operation ID.
Command or query A command mutates and returns 200 with an ID or 204; a query reads and projects.
HTTP verb and route Relative to the Group prefix — Post("/") becomes POST /api/heroes.
Request shape Body fields plus any route parameters. FastEndpoints binds both into one request record.
Response shape Or none, for a 204.
Failure modes Not found, conflict, forbidden — each needs a Produces(...) and a matching Send.*Async.

Read the full file on GitHub · 95 lines

Files

What ships with it

3 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.

  1. 9d ago First seen · 95 lines · 125 tokens per session scan A 12bac3a7535d

Subscribe to this mod's changes

add-slice is a skill published in the GitHub repository SSWConsulting/SSW.VerticalSliceArchitecture (398 stars, last pushed 1mo ago), licensed MIT. It adds 125 tokens to every session and 2,193 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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