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 rules/andr-ca/agentharness/docker-conventionsgit clone --depth 1 https://github.com/andr-ca/agentharnessWhat 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 | $0.00043 | $0.01211 |
| Opus 5 | $0.00022 | $0.00606 |
| Sonnet 5 | $0.00009 | $0.00242 |
| Haiku 4.5 | $0.00004 | $0.00121 |
Grade B, and why
docker-conventions scanned grade B with 2 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 yesterday.
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.
Recursive force deletemediumDestructive command
rm -rf with a variable or a broad path is one typo away from removing the wrong tree.
packages: `apt-get install -y ... && rm -rf /var/lib/apt/lists/*` Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
- Don't install `curl`, `wget`, or debugging tools in production images. How it starts
The opening of the file, as written. The whole thing — 172 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Docker Conventions
Best practices for Dockerfiles and container configurations. Focus areas: image size, build cache efficiency, security, and production readiness.
Base images
- Use official images with a pinned version tag:
python:3.12-slim,node:22-alpine,golang:1.24-alpine. - Prefer
slim(Debian-based, small) oralpine(even smaller, musl libc) variants. Avoidlatest— it changes without notice. - For production, prefer distroless or scratch (Go static binaries) to minimise the attack surface.
# Good: specific version, minimal base
FROM python:3.12-slim
# Bad: unpinned, full Debian base
FROM python:latest
Multi-stage builds
Use multi-stage builds to keep the production image small — the build tools (compilers, test runners, dev dependencies) stay in the build stage and never reach the final image.
# Stage 1: build
FROM node:22-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build
# Stage 2: production
FROM node:22-alpine AS production
WORKDIR /app
COPY --from=builder /app/dist ./dist
COPY --from=builder /app/node_modules ./node_modules
EXPOSE 3000
USER node
CMD ["node", "dist/index.js"]
Layer caching
Docker caches layers until a layer (or one of its inputs) changes. Copy dependency files before source code so the dependency install step is cached across code-only changes.
# Good: dependency install cached when only code changes
COPY package*.json ./
RUN npm ci
COPY . . # ← only invalidates layers from here down
# Bad: copies all source first — dependency install re-runs on every code change
COPY . .
RUN npm install
Security
Never embed secrets in a Dockerfile or in a layer. Secrets baked into a layer remain accessible in the image history even if deleted in a later layer.
# WRONG: secret in a layer (visible via `docker history`)
RUN echo "API_KEY=abc123" > /app/.env
# RIGHT: pass secrets at runtime via environment variable or a secret mount
# docker run -e API_KEY=$API_KEY ...
# or use BuildKit secrets for build-time:
RUN --mount=type=secret,id=api_key cat /run/secrets/api_key > /tmp/key
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.
- yesterday First seen · 172 lines · 43 tokens per session scan B a461c582ddc9
docker-conventions is a cursor rule published in the GitHub repository andr-ca/agentharness (1 stars, last pushed yesterday), licensed MIT. It adds 43 tokens to every session and 1,211 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 2 findings (recursive force delete, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
Other cursor rules, from other repositories
dreamd-recall
Recall lessons, decisions, and prior context from the .agent/ memory daemon. Use when starting work in a project that has a .agent/ folder, when the user references a past decision, or when you are about to make a choice that has a documented prior.
handoff
Export a Waybill Bundle by default, or import one when explicitly requested.
ui-motion-workflow
Orchestrate motion-aware UI work by sequencing direction, provider choice, implementation, and browser validation.
lemoncrow.execute
LemonCrow execute mode reference for Cursor.
prompt-routing
Route tasks to the correct Universal AI Engineering Prompt.
angular-20
This rule provides comprehensive best practices and coding standards for Angular development, focusing on modern TypeScript, standalone components, signals, and performance optimizations.