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/alchemiststudiosdotai/harness-engineering/execute-phasenpx skills add alchemiststudiosDOTai/harness-engineering --skill execute-phasegit clone --depth 1 https://github.com/alchemiststudiosDOTai/harness-engineeringWhat 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 | $0.00065 | $0.01962 |
| Opus 5 | $0.00032 | $0.00981 |
| Sonnet 5 | $0.00013 | $0.00392 |
| Haiku 4.5 | $0.00006 | $0.00196 |
Grade A, and why
execute-phase 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 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
- Bash(curl:*) How it starts
The opening of the file, as written. The whole thing — 344 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Execute Phase
Overview
Execute implementation plans from .artifacts/plan/ with strict discipline: gated checks, atomic commits, and a single living execution log.
North Star Rule
Follow the plan exactly. Do not improvise. Do not fix what isn't in the plan.
If something is ambiguous or missing, stop and ask the user.
When to Use
- User provides a plan path in
.artifacts/plan/ - User says "execute this plan" or "run the plan"
- User references a plan document for implementation
What This Skill Does NOT Do
| ❌ DON'T | ✅ DO INSTEAD |
|---|---|
| Re-plan the work | Execute tasks as written |
| Fix unrelated issues | Follow plan scope only |
| Skip quality gates | Run all gates, document failures |
| Ignore the plan | Plan is the source of truth |
Execute Phase Workflow
0. Input
User provides: $ARGUMENTS = path to plan in .artifacts/plan/
1. Read Plan & Lock Context
Read the FULL plan. Extract:
- Milestones
- Task IDs and order
- Acceptance tests
- Quality gates
- Success criteria
2. Pre-Flight Snapshot
Before any code changes:
# Capture git state
BRANCH=$(git branch --show-current)
SHA=$(git rev-parse --short HEAD)
STATUS=$(git status --short)
Create rollback point:
git add -A
git commit -m "rollback: before executing plan <topic>"
Create .artifacts/execute/YYYY-MM-DD_HH-MM-SS_<topic>.md:
---
title: "<topic> execution log"
link: "<topic>-execute"
type: debug_history
ontological_relations:
- relates_to: [[<plan-link>]]
tags: [execute, <topic>]
uuid: "<uuid>"
created_at: "<ISO-8601 timestamp>"
owner: "{{user}}"
plan_path: ".artifacts/plan/<file>.md"
start_commit: "<short_sha>"
env: {target: "local|staging|prod", notes: ""}
---
## Pre-Flight Checks
- Branch: <branch>
- Rollback commit: <sha>
- DoR satisfied: yes/no
- Access/secrets: present/missing
- Fixtures/data: ready/not ready
[If any NO → abort and add Blockers section]
3. Task-by-Task Execution
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 · 344 lines · 65 tokens per session scan A 65688e1d105d
execute-phase is a skill published in the GitHub repository alchemiststudiosDOTai/harness-engineering (104 stars, last pushed 5mo ago), licensed MIT. It adds 65 tokens to every session and 1,962 once invoked, about $0.0003 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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