# Complete Slice

> Implement a vertical slice from SLICES.md end-to-end using TDD. Use when user wants to code a slice of a project or mentions "complete slice

- **Type:** Skill
- **Install:** `agentstack add skill-ryan-scheinberg-harness-complete-slice`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [ryan-scheinberg](https://agentstack.voostack.com/s/ryan-scheinberg)
- **Installs:** 0
- **Category:** [AI & ML](https://agentstack.voostack.com/c/ai-and-ml)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [ryan-scheinberg](https://github.com/ryan-scheinberg)
- **Source:** https://github.com/ryan-scheinberg/harness/tree/main/skills/project-skillset/complete-slice

## Install

```sh
agentstack add skill-ryan-scheinberg-harness-complete-slice
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

Take one slice from `SLICES.md` and ship it. Often for dev work, but might be a different task that you should still complete to the standards of the company

## Process

1. **Read the slice and the brief.** Find the target slice. Internalize what it delivers. Read `PROJECT_BRIEF.md` for architectural context

2. **Orient in the codebase.** Module boundaries, test patterns, naming, DI style, config approach, what prior slices built. Your code should feel native — same seams, same style. Greenfield: scaffolding + test runner + lint + CI belong inside slice 1, not as separate phases

3. **Plan the TDD sequence.** Map acceptance criteria to red-green-refactor cycles. Start with the criterion that proves the core approach. Decide what's a real collaborator and what's a system boundary to mock. Keep the plan light. Use judgement for when to use TDD or take a different approach

4. **Build one test at a time.** Red → green → refactor. One failing test, minimum code to pass, clean up while green, next. Public interfaces only; mock system boundaries only; tests survive internal refactors. Writing all tests first produces tests that describe imagined behavior, not actual. See [tdd-reference.md](tdd-reference.md) for the full methodology

5. **Bake SRE in as you go.** Structured logs at decision points and error paths; metrics on the behaviors this slice introduces; health checks on new endpoints; errors that fail explicitly at boundaries with context; config externalized. Operational readiness isn't a final step — if it's not present when tests go green, it won't be added

6. **Verify.** All acceptance criteria met and covered by passing tests. Observable outcomes demonstrably work — run it, hit the endpoint, read the logs. Full suite green, not just new tests. No unrelated changes mixed in

7. **Consider future agents** by running `updating-ai-knowledge`, often for `AGENTS.md`

8. **Close the slice.** Check the boxes in `SLICES.md`. Follow-up work, discovered edge cases, or risks land in the relevant future slice, or in a `## Notes` section at the bottom of `SLICES.md`

9. **Report** what you shipped and verified back to whoever ran you

## Scope

Feature work, infrastructure-as-code, migrations, instrumentation, perf, bug fixes, deploy automation. Language, framework, and cloud agnostic

Not for: research spikes with no code deliverable, pure documentation, project planning (use `plan-to-slices`)

Skills you lean on: the `verify` subagent before declaring done, and a subagent for a second opinion or implementation partner

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [ryan-scheinberg](https://github.com/ryan-scheinberg)
- **Source:** [ryan-scheinberg/harness](https://github.com/ryan-scheinberg/harness)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-ryan-scheinberg-harness-complete-slice
- Seller: https://agentstack.voostack.com/s/ryan-scheinberg
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.