resource-lifecycle

A coding rule for managing resources from creation to cleanup. Every resource made in a start operation—such as a process, map entry, temporary file, or file handle—must be released in the matching end operation.

In plain words
What is it for?
Use it when implementing background jobs, process polling, cancellation, temporary logs, caches, or any code with setup and completion paths.
Why use it?
Without teardown, finished processes, files, and in-memory entries can remain behind and consume resources or leave stale state.

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/beardfaceguy/daimonos/resource-lifecycle
Clone the repo
git clone --depth 1 https://github.com/beardfaceguy/daimonos

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 297 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 $0.00000 $0.00297
Opus 5 $0.00000 $0.00148
Sonnet 5 $0.00000 $0.00059
Haiku 4.5 $0.00000 $0.00030

Measured yesterday against content hash f41bda165c6e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

resource-lifecycle 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 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.

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/resource-lifecycle.mdc · 33 lines

What it actually says

Complete Resource Lifecycle

When a function creates a resource (map entry, temp file, file handle, spawned process), the corresponding teardown path must clean it up.

What went wrong

bg() inserted into bg_processes and created /tmp/daimonos_bg_*.log. Neither poll() nor kill() ever called .remove() on the map or deleted the log file. The "create" half existed but the "destroy" half was missing.

Rule

  1. For every .insert() into a map, grep for the corresponding .remove(). If it doesn't exist, the lifecycle is incomplete.
  2. For every temp file created, ensure a remove_file() call exists on every exit path where the file is no longer needed.
  3. When implementing a "check status" function (like poll), handle the terminal state (process exited) by cleaning up — don't just report it.

Checklist for new bg/spawn patterns

  • Map entry removed when resource is done
  • Temp files deleted after final read
  • File handles dropped (not held past usefulness)
  • Test covers the full lifecycle: create → use → verify cleanup
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. yesterday First seen · 33 lines · 0 tokens per session scan A f41bda165c6e

Subscribe to this mod's changes

resource-lifecycle is a cursor rule published in the GitHub repository beardfaceguy/daimonos (2 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 297 tokens. 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.