dotnet-devcert-trust

dotnet-devcert-trust is a skill for Claude Code, Codex from ComeOnOliver/skillshub. It costs 50 tokens per session (4,084 once invoked), scanned D, a copy of dotnet-devcert-trust, MIT.

A guide for fixing trust problems with local .NET HTTPS certificates on Linux. These certificates let development services use encrypted HTTPS connections on your own computer.

In plain words
What is it for?
Use it when localhost HTTPS or .NET service connections report certificate errors, including on Ubuntu, Fedora, Arch, or WSL2.
Why use it?
Linux does not fully trust certificates created by the usual .NET command, which can cause HTTPS, Redis, Aspire, or service-to-service connections to fail.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Install

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.

agentmods
npx agentmods add skills/comeonoliver/skillshub/dotnet-devcert-trust
Any agent
npx skills add ComeOnOliver/skillshub --skill dotnet-devcert-trust
Clone the repo
git clone --depth 1 https://github.com/ComeOnOliver/skillshub

Made for: Claude Code, 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.

agentmods badge for dotnet-devcert-trust

README.md
[![agentmods](https://agentmods.dev/badge/skills/comeonoliver/skillshub/dotnet-devcert-trust.svg)](https://agentmods.dev/skills/comeonoliver/skillshub/dotnet-devcert-trust)
Your own site
<a href="https://agentmods.dev/skills/comeonoliver/skillshub/dotnet-devcert-trust"><img src="https://agentmods.dev/badge/skills/comeonoliver/skillshub/dotnet-devcert-trust.svg" alt="Measured on agentmods" height="20"></a>
Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,084 The whole file, excluding the scripts and references it only reads on demand.
Security scan D 3 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00050 $0.04084
Opus 5 $0.00025 $0.02042
Sonnet 5 $0.00010 $0.00817
Haiku 4.5 $0.00005 $0.00408

Measured 6d ago against content hash 7a3cb0c407f5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade D, and why

dotnet-devcert-trust scanned grade D with 3 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 6d 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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

sudo rm -f /usr/local/share/ca-certificates/aspnetcore-dev.crt

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

sudo rm -rf /usr/local/share/ca-certificates/aspnet/

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

This means .NET applications, OpenSSL, curl, and browsers all reject the dev certificate — even though `dotnet dev-certs https --check` reports it exists.
Origin

This is a copy

100% identical to dotnet-devcert-trust — 1 line differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/Aaronontheweb/dotnet-skills/dotnet-devcert-trust/SKILL.md · 416 lines

How it starts

The opening of the file, as written. The whole thing — 416 lines — stays where its author put it; the contents beside it link to each section on GitHub.

.NET Dev Certificate Trust on Linux

When to Use This Skill

Use this skill when:

  • Redis TLS connections fail with UntrustedRoot or RemoteCertificateNameMismatch in Aspire
  • dotnet dev-certs https --check --trust returns exit code 7
  • HTTPS localhost connections fail with certificate validation errors
  • After running dotnet dev-certs https --clean and needing to restore trust
  • Setting up a new Linux dev machine for .NET HTTPS development
  • Aspire dashboard or inter-service gRPC calls fail with TLS errors
  • Upgrading from Aspire < 13.1.0 (which didn't use TLS on Redis by default)

The Problem

On Windows and macOS, dotnet dev-certs https --trust handles everything automatically — it generates the certificate, installs it in the user store, and adds it to the system trust store. On Linux, it does almost nothing useful. The command generates the cert and places it in the user store, but:

  1. It does not export the certificate to the system CA directory
  2. It does not run update-ca-certificates to rebuild the CA bundle
  3. It does not add the cert to browser trust stores (NSS/NSSDB)
  4. The --trust flag silently succeeds but the cert remains untrusted

This means .NET applications, OpenSSL, curl, and browsers all reject the dev certificate — even though dotnet dev-certs https --check reports it exists.

Why This Surfaces with Aspire 13.1.0+

Prior to Aspire 13.1.0, Redis connections used plaintext. Starting with 13.1.0, Aspire enables TLS on Redis by default. If your dev cert isn't trusted at the system level, Redis connections fail immediately with:

System.Security.Authentication.AuthenticationException:
  The remote certificate is invalid because of errors in the certificate chain: UntrustedRoot

How Linux Certificate Trust Works

Understanding the architecture prevents cargo-cult debugging:

┌─────────────────────────────────────────────────────┐
│ Application (.NET, curl, OpenSSL)                   │
│   reads: /etc/ssl/certs/ca-certificates.crt         │
│          (consolidated CA bundle)                    │
└──────────────────────┬──────────────────────────────┘
                       │ built by
┌──────────────────────▼──────────────────────────────┐
│ update-ca-certificates                              │
│   reads from:                                        │
│     /usr/share/ca-certificates/      (distro CAs)   │
│     /usr/local/share/ca-certificates/ (local CAs)   │
│   writes to:                                         │
│     /etc/ssl/certs/ca-certificates.crt (bundle)     │
│     /etc/ssl/certs/*.pem (individual symlinks)      │
└─────────────────────────────────────────────────────┘

Read the full file on GitHub · 416 lines

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.

  1. 6d ago First seen · 416 lines · 50 tokens per session scan D 7a3cb0c407f5

Subscribe to this mod's changes

dotnet-devcert-trust is a skill published in the GitHub repository ComeOnOliver/skillshub (63 stars, last pushed 2mo ago), licensed MIT. It adds 50 tokens to every session and 4,084 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it D with 3 findings (asks for root, recursive force delete, makes network calls). It is 100% identical to dotnet-devcert-trust, differing in 1 line, and is treated as a copy.

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