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 instructions/thumbor/libthumbor/agents-mdgit clone --depth 1 https://github.com/thumbor/libthumborWhat 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 | $0.00679 | $0.00679 |
| Opus 5 | $0.00340 | $0.00340 |
| Sonnet 5 | $0.00136 | $0.00136 |
| Haiku 4.5 | $0.00068 | $0.00068 |
Grade A, and why
libthumbor AGENTS.md 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 today.
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.
How it starts
The opening of the file, as written. The whole thing — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
libthumbor is a Python library for composing and signing thumbor image URLs. It provides helpers for secure URL generation, URL parsing, and integration points that other applications can use to talk to thumbor safely.
Dev environment setup
-
Prerequisites: Python 3.10+ and Poetry
-
Install project and development dependencies:
make setupEquivalent to:
poetry install -
If you prefer running commands directly, use
poetry run ...so the virtual environment stays consistent with CI and local development.
Running tests
-
Full local validation flow:
make test -
Individual targets:
make unit make coverage make flake8 make pylint -
The test suite runs with
pytestand collects coverage for thelibthumborpackage.
Code style
- Formatter:
blackwith line length 88 and Python 3.10 target, configured in pyproject.toml. - Linter:
flake8with max complexity 20, configured in .flake8. - Static analysis:
pylint, configured in .pylintrc. - Primary workflow commands live in the Makefile; prefer them over ad hoc shell commands when possible.
Project structure
libthumbor/ <- main package
__init__.py <- package exports
crypto.py <- secure URL generation helpers
url.py <- URL composer and parsing utilities
tests/ <- pytest suite
test_cryptourl.py <- signing and encrypted URL behavior
test_libthumbor.py <- package-level behavior
test_url.py <- URL parsing and composition
test_url_composer.py <- URL builder coverage
test_generic_views.py <- Django integration coverage
README.md <- project overview and usage example
CONTRIBUTING.md <- contribution workflow notes
Makefile <- common setup, test, and lint tasks
pyproject.toml <- Poetry metadata and tool configuration
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.
- today First seen · 91 lines · 679 tokens per session scan A 87475304754e
libthumbor AGENTS.md is an instructions file published in the GitHub repository thumbor/libthumbor (64 stars, last pushed yesterday), licensed MIT. It adds 679 tokens to every session, about $0.0034 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 2026-09-01.
Other instructions, from other repositories
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Instructions for dotnet/maui, covering ui testing guidelines for .net maui, ui test structure, two-project requirement, base class and infrastructure and naming conventions.
maui copilot-instructions.md
Guidance for GitHub Copilot when working on the .NET MAUI repository.
maui helix-device-tests.instructions.md
Guidelines for running and configuring .NET MAUI device tests on Helix infrastructure.
maui ci-copilot-pipeline-security.instructions.md
Security rules for the Copilot PR-review pipeline. Read before editing.
maui xaml-unittests.instructions.md
Guidelines for writing XAML unit tests in the Controls.Xaml.UnitTests project.
maui collectionview-handler-detection.instructions.md
Critical guidance for CollectionView/CarouselView handler detection.