finding-fail-open-flaws SKILL.md skillA
finding-fail-open-flaws from unboundcompute/security-agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add unboundcompute/security-agent-skills/finding-fail-open-flaws@git:20260816.e670f56Pins git:20260816.e670f56 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- unboundcompute/security-agent-skills
- Path
skills/finding-fail-open-flaws/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260816.e670f56, committed Aug 16, 2026
- Size
- 6,186 bytes
- Repository stars
- 26
- License
- MIT
Find security controls that grant access when they should deny it: an authorization check that returns allow on error or timeout, an empty or wildcard allowlist that matches everything, a default-allow branch when input is missing or unrecognized, and a caught exception that swallows a denial and continues. Use when reviewing authentication, authorization, or any gate whose failure path matters, or when a check "passes" for reasons you have not confirmed. The dangerous default is allow; prove…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Finding fail-open flaws: prove the gate denies by default A control fails open when its error, empty, or default path grants access instead of refusing it. The check looks present and even passes its happy-path tests, but on the branch that runs when something goes wrong, when a lookup errors, a list is empty, a value is missing, an exception is caught, it lets the request through. These flaws hide in the paths tests rarely cover, and they turn any upstream failure into an authorization bypass. ## When to use - You are reviewing authentication, authorization, or any access gate. - A check "passes" and you have not confirmed why, or what it does on failure. - A control depends on an external service, a list, or an input that could be absent. ## Scope check Test gates in code you own or are authorized to test, inducing failures against your own environment. If you can't name the authorization, stop. ## The loop 1. **Enumerate the gates and their failure branches.** For each authentication or authorization check in scope, find not just the allow/deny decision but what happens when the check cannot be completed: the lookup throws, the policy service …
Read the whole file at its exact version.
How to install
mdr add unboundcompute/security-agent-skills/finding-fail-open-flaws@sha256:1585d68ba73db9c3The line at the top of this page pins the label git:20260816.e670f56, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_uhbg3nyawuwascd7)
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Versions
The registry has recorded 1 version of this file, committed on Aug 16, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (6186 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
unboundcompute/security-agent-skills · 26 stars · license MIT · pushed 2026-09-08 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_uhbg3nyawuwascd7 GET https://markdownregistry.com/api/v1/resolve?ref=unboundcompute/security-agent-skills/finding-fail-open-flaws GET https://markdownregistry.com/api/v1/blob/1585d68ba73db9c30d3d64aa6192b7a9e61dbd5c6de81bf543bcd976f4c7d8e6
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.