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/ericrisco/rsc-harness/implementnpx skills add ericrisco/rsc-harness --skill implementgit clone --depth 1 https://github.com/ericrisco/rsc-harnessWrote 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/ericrisco/rsc-harness/implement)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/implement"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/implement.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 | $0.00123 | $0.05803 |
| Opus 5 | $0.00062 | $0.02901 |
| Sonnet 5 | $0.00025 | $0.01161 |
| Haiku 4.5 | $0.00012 | $0.00580 |
Grade A, and why
implement 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.
How it starts
The opening of the file, as written. The whole thing — 388 lines — stays where its author put it; the contents beside it link to each section on GitHub.
implement — turn the task list into tested code
You have a spec, a plan, and an ordered task list (from specify → plan → tasks), and the
analyze gate has cleared. This skill does the building: it walks the tasks in order, writes each
one test-first, stops to show its work after every task, and records the decisions it makes
along the way. It is the intent → shipped code engine's hands — verify is the gate that comes
after, not part of this skill.
This is a process skill. It owns the discipline (red → green → refactor, checkpoints, decision
logging, constitution adherence). It does not own the test tooling — pytest fixtures, go test
table-drivers, Vitest/Playwright, flutter test — those belong to the stack skill, and you call
into them rather than reinventing them.
Before you write a line of code
Run this short gate. Skipping it is the most common way an implement session goes sideways. This gate is a hard refuse, not a checklist to feel good about: if it fails you stop and route back — you do not write feature code anyway.
- The spec + plan must exist AND be approved. Open the spec (
02-DOCS/wiki/sdd/specs/<slug>.md), the plan (02-DOCS/wiki/sdd/plans/<slug>.md, which holds the task list), and the constitution (02-DOCS/wiki/sdd/constitution.md). If any is missing, you are not allowed to implement — route back: no spec →specify; no plan →plan; no task list inside the plan →tasks; unresolvedanalyzefindings → resolve them first. If a spec/plan exists but the user has not actually seen and approved it, get that approval first. Never "start coding to discover the plan as you go", and never accept "just build it, skip the spec" on a non-trivial feature — name the gate in one friendly line and route tospecify. (Only a true one-line, low-risk change earns a skip, and you say so.) - Read the SDD runtime config. Open
02-DOCS/wiki/sdd/config.yaml. If it is missing on non-trivial work, stop and route tosdd-init. Usetesting.strict_tdd,testing.commands.apply,testing.commands.verify,sdd.review_budgetandsdd.registry_path. Do not choose a different test command from memory while config exists. - Read the skill registry. Open
.rsc/skill-registry.jsonif present. Select only the relevant stack/process skills for this task, then digest them into compact rules. If the registry is missing, run or recommendnpx @ericrisco/rsc registry refreshand record the fallback. - Read the accompaniment dial. Open
02-DOCS/wiki/harness/user-profile.mdand read the technical + accompaniment level. It sets how loud you are at each checkpoint (see the dial table below). No profile yet → assume non-technical, narrate more, and ask before any irreversible step. - Confirm isolation. Implementation happens on a feature branch or worktree, never directly on
the default branch. If you are on
main/master, stop and hand toworktreesbefore the first commit. - Scan the tasks for independence. Mark which tasks share files/state and which are disjoint.
Disjoint clusters are candidates for
parallel; everything else runs in order.
What ships with it
6 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.
- 2d ago First seen · 388 lines · 123 tokens per session scan A 34be01180fb7
implement is a skill published in the GitHub repository ericrisco/rsc-harness (64 stars, last pushed 3d ago), licensed MIT. It adds 123 tokens to every session and 5,803 once invoked, about $0.0006 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 2026-09-03.
Other skills, from other repositories
moai-workflow-tdd
Test-Driven Development workflow specialist using RED-GREEN-REFACTOR cycle for test-first software development. Use when developing new features from scratch or when behavior specification drives implementation.
test-writing
Writes meaningful tests that actually catch bugs.
dev-tdd
TDD development with Red-Green-Refactor cycle. Use to implement a feature by writing tests BEFORE the code. Trigger automatically when the user asks for TDD, wants to write tests first, mentions "test first", or asks to implement, add, create, fix, correct code, a new feature, a bugfix, or a functionality.
test-first-agent-loop
Require builders to run validation, reviewers to demand evidence, and all agents to record failures honestly instead of claiming success without test results.
auto
Drive an autonomous execution arc end-to-end — compose brainstorm→spec→/prospect→plan→/prospect→TDD→/retrospect under the Rule 35 posture, decide objectively-validatable forks yourself, and stop only on a load-bearing fork or an ungranted approval. Modes: arc (default), execute (skip ideation), plan (stop at a…
tdd
Drives feature work and bug fixes through a tight failing-test-first loop. Trigger when implementing, fixing, or refactoring behavior in a codebase that already has tests. Skip for spikes, visual-only edits, throwaway scripts, and generated files.