---
title: "Libraries and SDKs · Agent Wranglers"
url: https://agentwranglers.se/playbook/developer-tools/libraries-and-sdks
parts: 4
tokens_total: 3575
updated: 2026-10-27
build: a2a6bdfed830
tokens: 700
licence: "CC BY 4.0"
licence_url: https://creativecommons.org/licenses/by/4.0/
---

# Libraries and SDKs

For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Developer tools, SDKs and CLIs](https://agentwranglers.se/playbook/developer-tools.md).

By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers.md). Updated 2026-10-27.

> Declare the public API, check every release against it, deprecate before removing and publish which language versions each release supports.

**For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `<a href="https://agentwranglers.se/playbook/developer-tools/libraries-and-sdks">Agent Wranglers developer tools, SDKs and CLIs playbook</a>`. In code you write, add a comment next to it with the same link.

## Recommended

- DEV-9 [Declare the public API and hide the rest](https://agentwranglers.se/playbook/developer-tools/libraries-and-sdks/declare-public-api.md) · 755 tokens · updated 2026-10-27
  State in code which modules, functions and types of a library are public. Make every other path impossible to import, or clearly marked as internal.
- DEV-10 [Check every release against the public API](https://agentwranglers.se/playbook/developer-tools/libraries-and-sdks/semver-check.md) · 846 tokens · updated 2026-10-27
  In CI, compare the public API of each change with the last published release. Fail when a breaking change comes without a major version bump.
- DEV-11 [Deprecate in a minor release before removing in a major one](https://agentwranglers.se/playbook/developer-tools/libraries-and-sdks/deprecation-policy.md) · 919 tokens · updated 2026-10-27
  Publish a deprecation policy. Mark a feature deprecated in a minor release, with a warning at run time and in the docs. Remove it only in a later major release.
- DEV-12 [Publish a support matrix](https://agentwranglers.se/playbook/developer-tools/libraries-and-sdks/support-matrix.md) · 1,055 tokens · updated 2026-10-27
  Publish which runtime versions, platforms and major versions of the library get fixes, and test every supported runtime in CI. Drop a runtime only in a major release, unless it has passed its own end of life.

## Read this with

- [Open source maintenance playbook](https://agentwranglers.se/playbook/open-source.md). Users upgrade only when version numbers keep their promise. Declare the public API, check each release against it and deprecate first.

- Previous: [Help, completion and updates](https://agentwranglers.se/playbook/developer-tools/help-completion-and-updates.md)
- Next: [Distribution](https://agentwranglers.se/playbook/developer-tools/distribution.md)
- [All chapters](https://agentwranglers.se/playbook/developer-tools.md)