Borrowing it
Nothing to install: this file belongs to ibuilder/massing. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/ibuilder/massing/main/AGENTS.mdgit clone --depth 1 https://github.com/ibuilder/massingWrote 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/instructions/ibuilder/massing/agents-md)<a href="https://agentmods.dev/instructions/ibuilder/massing/agents-md"><img src="https://agentmods.dev/badge/instructions/ibuilder/massing/agents-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/ibuilder/massing/agents-md"><img src="https://agentmods.dev/badge/instructions/ibuilder/massing/agents-md.svg" alt="Reviewed on agentmods" width="80" 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 | $0.01132 | $0.01132 |
| Opus 5.5 | $0.00453 | $0.00453 |
| Sonnet 5.5 | $0.00226 | $0.00226 |
| Haiku 4.5 | $0.00113 | $0.00113 |
Grade A, and why
massing AGENTS.md 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 2mo 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.
check: `curl http://localhost:8000/health` → `{"status":"ok"}`. How it starts
The opening of the file, as written. The whole thing — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
Cursor Cloud specific instructions
This section is for Cloud Agents running in an environment where the startup update script has
already installed dependencies. It captures the non-obvious bits of running Massing here; standard
commands and product detail live in the README, docs/getting-started.md, and the .claude/skills/.
What the update script already did
- Installed the web workspace deps (
npm install, which also runsapps/webpredevWASM copy). - Ensured Node 24 is installed via
nvm(the repo requiresnode >=24; Node 18 breaks the web build). - Installed the Python API deps into the user site (
~/.local):services/api/requirements.lock(runtime, hash-pinned, py3.12/Linux — matches prod) andservices/api/requirements-dev.txt(test/lint: httpx, ruff, bandit, pytest, coverage, DracoPy).services/data's deps are a strict subset of the lock, so there is no separate install for it.
Services (all run from source in dev)
| Service | Path | Dev run command | Port |
|---|---|---|---|
| Web (Vite + TS viewer/authoring UI) | apps/web |
npm run dev |
5173 |
API (FastAPI; bundles the services/data ifcopenshell library) |
services/api |
uvicorn aec_api.main:app --reload |
8000 |
Postgres + MinIO are not needed for dev: the API defaults to SQLite (sqlite:///./aec.db) and
local filesystem storage. Docker/docker compose --profile full is the self-host path, not required
here. The converter (Node IFC→Fragments) is job-style/optional — the API reconverts in-process on publish.
Node 24 gotcha (important)
/exec-daemon/node (v22) sits first on PATH and shadows nvm's Node 24 even after nvm use 24.
Before any web command, put Node 24 first explicitly:
export NVM_DIR="$HOME/.nvm"; . "$NVM_DIR/nvm.sh"; export PATH="$(nvm which 24 | xargs dirname):$PATH"
node -v # must print v24.x
Running the two dev servers
Start each in its own long-lived terminal (e.g. tmux). The web app in dev calls the API at
http://localhost:8000 (see apps/web/src/api/httpCore.ts); CORS default already allows the Vite origin.
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.
- 2mo ago First seen · 67 lines · 1,132 tokens per session scan A c03eb8d98e54
massing AGENTS.md is an instructions file published in the GitHub repository ibuilder/massing (132 stars, last pushed today), licensed MIT. It adds 1,132 tokens to every session, about $0.0045 per session on Opus 5.5. 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.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.