caddy-security is a security application and set of plugins for Caddy v2, a web server, that handles user authentication and controls access to HTTP requests. It supports methods including local, LDAP, OpenID Connect, OAuth 2.0, SAML, JWT, and PASETO, and is used to protect web services behind Caddy.
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 skills add greenpau/caddy-security --skill configuration-authentication-user-transformsgit clone --depth 1 https://github.com/greenpau/caddy-securityWrote 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.
[](https://agentmods.dev/skills/greenpau/caddy-security/configuration-authentication-user-transforms)<a href="https://agentmods.dev/skills/greenpau/caddy-security/configuration-authentication-user-transforms"><img src="https://agentmods.dev/badge/skills/greenpau/caddy-security/configuration-authentication-user-transforms/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/greenpau/caddy-security/configuration-authentication-user-transforms"><img src="https://agentmods.dev/badge/skills/greenpau/caddy-security/configuration-authentication-user-transforms.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00044 | $0.02531 |
| Opus 5.5 | $0.00018 | $0.01012 |
| Sonnet 5.5 | $0.00009 | $0.00506 |
| Haiku 4.5 | $0.00004 | $0.00253 |
Grade A, and why
configuration-authentication-user-transforms 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 — 233 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Configuration Authentication User Transforms
Use for transform user or transform users inside an authentication portal.
caddyfile_authn_transform.go forwards the complete block to the selected
module's pkg/authn/transformer/parser; provisioning resolves individual
arguments and compiles the result again. Inspect go list -m -json github.com/greenpau/go-authcrunch before relying on sibling source. The
selected library supports the grammar below.
The surrounding portal configuration owns wiring; static users own stored challenge rules. The authentication flow contract owns login and profile API behavior. Load those details only when changing the corresponding boundary, rather than reloading the portal router for a transform.
Matchers and actions
Every block needs at least one matcher and one action. Conditions combine as
match-all. Ordinary bare match retains the historical exact match spelling
in adapted JSON; match any stays unconditional and match github retains its
provider-specific spelling, including malformed statements for shared validation.
Classification uses the shared parser, so a claim value containing the word match remains an action.
These are alternative statements inside a transform, not a complete config:
match any
match realm local
field email exists
field picture not exists
partial match email @example.com
no regex match any role ^authp/(admin|user)$
action add role authp/user
action overwrite roles authp/user
action drop matched role
action delete org
require mfa
deny
ui link "User Profile" /auth/profile/ icon "las la-cog" target_blank
ACL strategies are exact, partial, prefix, suffix, and regex, with
optional no and any according to pkg/acl/condition.go. Field aliases come
from pkg/acl/acl.go: for example role/group/groups → roles, mail →
email, and subject → sub. amr is a list of verified methods.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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 · 233 lines · 44 tokens per session scan A 10ad1e1c84e0
configuration-authentication-user-transforms is a skill published in the GitHub repository greenpau/caddy-security (2,263 stars, last pushed today), licensed Apache-2.0. It adds 44 tokens to every session and 2,531 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-10-25.
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