What is authentication-portal-challenges?

A set of code and policy instructions for managing conditional login challenges and related authentication data. It covers rules for factors such as passwordless WebAuthn, verified authentication claims, policy validation, and rechecking access after policy changes.

Use it to parse, validate, store, resolve, and revalidate authentication challenge policies and registered login factors.

It helps keep authentication-policy changes consistent across login, refresh, OpenID Connect, and direct authentication flows. OpenID Connect is a standard for signing users into applications through an identity provider.

How greenpau/go-authcrunch configures Codex

Reuse

Borrowing it

Nothing to install: this file belongs to greenpau/go-authcrunch. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/greenpau/go-authcrunch/main/.codex/skills/authentication-portal-challenges/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/greenpau/go-authcrunch

Made for: Codex.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/greenpau/go-authcrunch/authentication-portal-challenges/github.svg)](https://agentmods.dev/skills/greenpau/go-authcrunch/authentication-portal-challenges)

Your own site

<a href="https://agentmods.dev/skills/greenpau/go-authcrunch/authentication-portal-challenges"><img src="https://agentmods.dev/badge/skills/greenpau/go-authcrunch/authentication-portal-challenges/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/greenpau/go-authcrunch/authentication-portal-challenges"><img src="https://agentmods.dev/badge/skills/greenpau/go-authcrunch/authentication-portal-challenges.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 4,269 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.

Model	Per session	Once invoked
Fable 5.1	$0.00069	$0.04269
Opus 5.5	$0.00028	$0.01708
Sonnet 5.5	$0.00014	$0.00854
Haiku 4.5	$0.00007	$0.00427

Measured 12d ago against content hash c23ed65b64a4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

authentication-portal-challenges 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 12d 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.

.codex/skills/authentication-portal-challenges/SKILL.md · 347 lines

How it starts

The opening of the file, as written. The whole thing — 347 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Authentication Challenge Policies

Ownership and public configuration

pkg/authchal/config.AuthenticationChallengeConfig owns typed ordered rules and validation. authchal.Rule and authchal.Ruleset remain aliases, and authchal.NewRuleset preserves its rule-body signature by calling the parser. pkg/authchal/parser.NewAuthenticationChallengeConfigFromDirectives(statements) accepts encoded rule bodies after auth challenges, without the prefix or braces. It returns *config.AuthenticationChallengeConfig. Its Statements can be applied through local.IdentityStore.OverwriteUserAuthChallengeRules; its typed Rules, Validate, and ResolveChallenges support other consumers. Stored policies with no eligible rule deny login; an empty stored policy clears explicit selection and restores backend defaults. Validate a replacement before mutating the user. Policy changes invalidate credential evidence.

Authenticated self-service uses the existing profile operations documented in the profile authentication-flow API contract. Keep UI request/response fields, registered/effective policy previews, reset, and reauthentication guidance there. The profile adapter consumes this same public rule parser; it must not introduce a second grammar.

pkg/authn/transformer/config.Config owns the established serialized Matchers and Actions string lists; transformer.Config is its compatible alias. pkg/authn/transformer/parser.NewUserTransformerConfigFromDirectives(statements) accepts one transform user block body, without header or braces, and returns that configuration. Append the result to PortalConfig.UserTransformerConfigs. CompileUserTransformerConfig owns decoding and validation of typed/persisted string lists as well; transformer.NewFactory uses its detached RuntimeConfig. Keep decoding in the parser, not a second implementation in the runtime. These lower configuration packages avoid parser/runtime import cycles.

Read the full file on GitHub · 347 lines

Files

What ships with it

2 files 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.

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.

12d ago Changed · +6 lines c23ed65b64a4
17d ago Changed · +33 lines e5b32582e343
26d ago Changed · +15 lines 0ccd28124fb5
29d ago Changed · +13 lines 68da9e1245b4
1mo ago Changed · +41 lines · +7 tokens per session 7b802a9ac720
1mo ago Changed · -53 lines 454c375b6d1f
1mo ago First seen · 292 lines · 62 tokens per session scan A 3dfe906f41d3

Subscribe to this mod's changes

authentication-portal-challenges is a skill published in the GitHub repository greenpau/go-authcrunch (60 stars, last pushed 10d ago), licensed Apache-2.0. It adds 69 tokens to every session and 4,269 once invoked, about $0.0003 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 2026-09-20.