file-placement-policy

A set of rules for deciding where new files and folders may be created in an existing project. It checks the project's guarded paths and requires permission before adding files in protected locations.

In plain words
What is it for?
Use it before creating files in places such as the project root, docs, source code, tests, configuration, or logs. It helps an agent know when to stop and ask for approval.
Why use it?
It prevents accidental changes to important project areas and keeps new files within the project's agreed structure. It also records approved exceptions for future checks.

Cursor rule for Cursor

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 rules/andr-ca/agentharness/file-placement-policy
Clone the repo
git clone --depth 1 https://github.com/andr-ca/agentharness

Made for: Cursor.

Per session 63 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 563 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 $0.00063 $0.00563
Opus 5 $0.00032 $0.00282
Sonnet 5 $0.00013 $0.00113
Haiku 4.5 $0.00006 $0.00056

Measured 2d ago against content hash e0ed9bf0d6db, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

file-placement-policy 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.

.cursor/rules/file-placement-policy.mdc · 70 lines

How it starts

The opening of the file, as written. The whole thing — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.

File Placement Policy

Load this skill at session start if the project has .agentharness-guarded-paths.json. Read the file before touching anything.

Rule: check before creating

Before creating any new file or directory, check whether the target location is guarded:

python3 -c "
import json
d = json.load(open('.agentharness-guarded-paths.json'))
print('Root guarded:', d['guard_root_level_new_items'])
print('Guarded dirs:', d['guarded_dirs'])
"

If the path is guarded: stop and ask the user for permission.

What counts as guarded

  • Any new file at the root level (when guard_root_level_new_items: true)
  • Any file under src/, docs/, tests/, conf/, logs/, etc.
  • Any root-level config file already listed in guarded_root_files

Asking for permission

"I need to create docs/architecture/NEW_SECTION.md to document X. This is in the guarded docs/ directory. May I proceed?"

Wait for an explicit yes/ok/go ahead response.

After getting permission: record it

Add the approved path to .agentharness-allowed-additions.txt:

echo "docs/architecture/NEW_SECTION.md" >> .agentharness-allowed-additions.txt

The pre-commit hook reads this file to allow the commit.

No guarded-paths file = early-stage project

If .agentharness-guarded-paths.json doesn't exist:

  1. Run: python3 tools/analyze_structure.py . --recommend
  2. Present the recommendations to the user.
  3. If accepted, create the structure and generate the config: python3 tools/analyze_structure.py . --output .agentharness-guarded-paths.json

Pre-commit enforcement

The hook at tools/check-file-placement.sh runs automatically before every commit. If a staged file is in a guarded location and not in .agentharness-allowed-additions.txt, the commit is blocked with a clear message.

Reference

Full protocol: patterns/file-placement-policy/POLICY.md Analyzer: tools/analyze_structure.py Hook: tools/check-file-placement.sh

Read the full file on GitHub · 70 lines

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 · 70 lines · 63 tokens per session scan A e0ed9bf0d6db

Subscribe to this mod's changes

file-placement-policy is a cursor rule published in the GitHub repository andr-ca/agentharness (1 stars, last pushed 2d ago), licensed MIT. It adds 63 tokens to every session and 563 once invoked, about $0.0003 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.