ssl-certificate

ssl-certificate is a skill for Claude Code, Codex from vladkesler/initrunner. It costs 27 tokens per session (452 once invoked), scanned A, original, Apache-2.0.

A skill for checking whether an HTTPS website’s SSL/TLS certificate is valid, matches its hostname, and is close to expiring. SSL/TLS certificates help prove a website’s identity and encrypt its traffic.

In plain words
What is it for?
Use it to inspect certificate dates, issuers, hostname matches, certificate chains, and expiry risk for website endpoints.
Why use it?
It helps catch expired, misconfigured, or soon-to-expire certificates before users receive security warnings or connections 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/vladkesler/initrunner/ssl-certificate
Any agent
npx skills add vladkesler/initrunner --skill ssl-certificate
Clone the repo
git clone --depth 1 https://github.com/vladkesler/initrunner

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 ssl-certificate

README.md
[![agentmods](https://agentmods.dev/badge/skills/vladkesler/initrunner/ssl-certificate.svg)](https://agentmods.dev/skills/vladkesler/initrunner/ssl-certificate)
Your own site
<a href="https://agentmods.dev/skills/vladkesler/initrunner/ssl-certificate"><img src="https://agentmods.dev/badge/skills/vladkesler/initrunner/ssl-certificate.svg" alt="Measured on agentmods" height="20"></a>
Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 452 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00027 $0.00452
Opus 5 $0.00014 $0.00226
Sonnet 5 $0.00005 $0.00090
Haiku 4.5 $0.00003 $0.00045

Measured 6d ago against content hash c714e61a8757, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

ssl-certificate 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 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.

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.

examples/roles/api-monitor/skills/ssl-certificate/SKILL.md · 68 lines

What it actually says

SSL/TLS certificate checking skill.

When to activate

  • When the user asks about SSL or certificate status
  • As a periodic deep check (check memory for last SSL check date -- run at most once per week per endpoint)

Check command

echo | openssl s_client -connect <host>:443 -servername <host> 2>/dev/null | openssl x509 -noout -dates -subject -issuer

Replace <host> with the hostname extracted from the endpoint URL (strip the protocol and path).

Parsing output

The command returns:

  • notBefore= -- certificate start date
  • notAfter= -- certificate expiry date
  • subject= -- certificate subject (CN and/or SAN)
  • issuer= -- certificate issuer (CA name)

Calculate days until expiry from the notAfter date using the current timestamp from datetime.

Alert thresholds

Days remaining Severity
> 30 No alert
14-30 Warning
7-14 Warning (urgent)
1-7 Critical
0 or expired Critical (emergency)

Additional checks

  • Subject match: Verify the CN or SAN matches the hostname being checked. Mismatches indicate a misconfigured certificate.
  • Issuer: Check if the issuer is a recognized CA. Self-signed certificates in production are a finding.

MUST

  • Include the exact expiry date and days remaining in the alert
  • Include the hostname checked and the issuer name
  • Store the SSL check result in semantic memory with category "ssl_check" to avoid redundant checks

MUST NOT

  • Alert on self-signed certificates for staging/dev URLs (check if the URL contains "staging", "dev", "local", "localhost", "test")
  • Run SSL checks more than once per week per endpoint (check memory first)
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 · 68 lines · 27 tokens per session scan A c714e61a8757

Subscribe to this mod's changes

ssl-certificate is a skill published in the GitHub repository vladkesler/initrunner (41 stars, last pushed 5d ago), licensed Apache-2.0. It adds 27 tokens to every session and 452 once invoked, about $0.0001 per session on Opus 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 2026-08-30.