resource-lifecycle-checker

resource-lifecycle-checker is an agent for Claude Code from ReviewToolkits/cext-review-toolkit. It costs 109 tokens per session (2,027 once invoked), scanned A, original, MIT.

A code-review agent for finding leaks of non-Python resources in C extensions, including allocated memory, HDF5 handles, buffers, and file descriptors.

In plain words
What is it for?
Use it to audit malloc/free pairs, HDF5 handle cleanup, buffer-protocol release logic, and file-descriptor management.
Why use it?
It finds resources that are not released on every exit path, especially when an error occurs.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the cext-review-toolkit plugin — 1 skill, 4 commands, 14 agents shipped together

Good fit Use it to audit malloc/free pairs, HDF5 handle cleanup, buffer-protocol release logic, and file-descriptor management.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/reviewtoolkits/cext-review-toolkit/resource-lifecycle-checker
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.

Clone the repo
git clone --depth 1 https://github.com/ReviewToolkits/cext-review-toolkit

Made for: Claude Code.

Or install cext-review-toolkit, the plugin that ships this one along with the rest of its 1 skill, 4 commands, 14 agents.

Wrote 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.

agentmods badge for resource-lifecycle-checker

README.md
[![agentmods](https://agentmods.dev/badge/agents/reviewtoolkits/cext-review-toolkit/resource-lifecycle-checker.svg)](https://agentmods.dev/agents/reviewtoolkits/cext-review-toolkit/resource-lifecycle-checker)
Your own site
<a href="https://agentmods.dev/agents/reviewtoolkits/cext-review-toolkit/resource-lifecycle-checker"><img src="https://agentmods.dev/badge/agents/reviewtoolkits/cext-review-toolkit/resource-lifecycle-checker.svg" alt="Measured on agentmods" height="20"></a>
Per session 109 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,027 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00109 $0.02027
Opus 5 $0.00055 $0.01014
Sonnet 5 $0.00022 $0.00405
Haiku 4.5 $0.00011 $0.00203

Measured 8d ago against content hash 16d6f781dba8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

resource-lifecycle-checker 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 8d 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.

plugins/cext-review-toolkit/agents/resource-lifecycle-checker.md · 175 lines

How it starts

The opening of the file, as written. The whole thing — 175 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert in resource management in C code. Your goal is to find non-PyObject resource leaks in C extension code -- memory from malloc/PyMem_Malloc, HDF5 handles, buffer protocol resources, and file descriptors that are not properly freed on all exit paths (especially error paths).

Preflight Orientation (read first)

If reports/<extension>_v1/preflight/generated_code_map.md exists, read it before Phase 1. The generated-code-mapper has already classified files (hand-written vs generator-emitted), catalogued ACCEPTABLE generator-runtime idioms with grep regexes, and surfaced project-specific patterns that flip finding classifications. Apply its orientation to:

  • Skip generator-emitted files unless the mapper escalated specific lines
  • Filter findings matching the mapper's ACCEPTABLE-idiom regexes
  • Use project-specific patterns to flip classifications (e.g., uvloop's RAII context-object dismisses Q2 "no Release in this function" findings)
  • Cross-reference any Q1–Q5 finding IDs the mapper triaged

If no preflight exists, proceed normally.

Key Concepts

This agent complements the refcount-auditor. The refcount-auditor tracks PyObject* reference counting. This agent tracks everything else: raw memory, library handles, and protocol resources.

Error paths are where resource leaks hide. The happy path usually frees everything. It's the error paths -- early returns after allocation but before cleanup -- where resources leak. The classic pattern:

// LEAKED on error path:
buf = malloc(size);
result = PyUnicode_FromString(buf);
if (result == NULL) {
    return NULL;  // BUG: buf leaked!
}
free(buf);  // Only reached on success
return result;

The goto cleanup pattern is the standard fix:

buf = malloc(size);
result = PyUnicode_FromString(buf);
if (result == NULL)
    goto cleanup;
// ... success ...
cleanup:
    free(buf);
    return result;

Resource categories tracked by the scanner:

  • C memory: malloc/calloc/realloc -> free
  • Python memory: PyMem_Malloc/PyMem_Calloc -> PyMem_Free
  • Python object memory: PyObject_Malloc/PyObject_Calloc -> PyObject_Free
  • Buffer protocol: PyObject_GetBuffer -> PyBuffer_Release
  • HDF5 types: H5Tcreate/H5Tcopy/H5Tget_member_type -> H5Tclose
  • HDF5 dataspaces: H5Screate/H5Screate_simple/H5Dget_space -> H5Sclose
  • HDF5 datasets/groups/attributes/properties: corresponding create/open -> close
  • File I/O: fopen -> fclose

Read the full file on GitHub · 175 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. 8d ago First seen · 175 lines · 0 tokens per session scan A 16d6f781dba8

Subscribe to this mod's changes

resource-lifecycle-checker is an agent published in the GitHub repository ReviewToolkits/cext-review-toolkit (28 stars, last pushed 1mo ago), licensed MIT. It adds 109 tokens to every session and 2,027 once invoked, about $0.0005 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 2026-08-30.

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