complete-slice

A procedure for implementing one vertical slice from SLICES.md using test-driven development (TDD), where tests guide the code through failing, passing, and cleanup stages. It first considers the project brief, architecture, and existing patterns.

In plain words
What is it for?
Use it when completing a project slice end to end, including acceptance tests, implementation, dependency boundaries, and project setup when needed.
Why use it?
It turns one slice description into a focused, tested change that fits the surrounding code.

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/ryan-scheinberg/harness/complete-slice
Any agent
npx skills add ryan-scheinberg/harness --skill complete-slice
Clone the repo
git clone --depth 1 https://github.com/ryan-scheinberg/harness

Made for: Claude Code, Codex.

Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 614 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 $0.00037 $0.00614
Opus 5 $0.00018 $0.00307
Sonnet 5 $0.00007 $0.00123
Haiku 4.5 $0.00004 $0.00061

Measured 2d ago against content hash e34feefe9955, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

complete-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 2d 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.

skills/project-skillset/complete-slice/SKILL.md · 35 lines

How it starts

The opening of the file, as written. The whole thing — 35 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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 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

Read the full file on GitHub · 35 lines

Files

What ships with it

1 file 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. 2d ago First seen · 35 lines · 37 tokens per session scan A e34feefe9955

Subscribe to this mod's changes

complete-slice is a skill published in the GitHub repository ryan-scheinberg/harness (2 stars, last pushed 1mo ago), licensed MIT. It adds 37 tokens to every session and 614 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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