check-upstream

check-upstream is a skill for Claude Code, Codex from pdugan20/claudelint. It costs 57 tokens per session (873 once invoked), scanned A, original, MIT.

A tool for comparing the current Claude Code documentation with the rules and schemas used by claudelint. Schema means the defined structure and allowed fields of a configuration file.

In plain words
What is it for?
It is for refreshing the documentation baseline, reviewing changes, detecting new documentation pages, and recommending schema or rule updates.
Why use it?
It reveals when Claude Code changes while the validator still follows older documentation, helping identify outdated checks and missing rules.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code; installed under .agents/ (shared by several agents).

Part of the claudelint plugin — 10 skills, 1 agent, 1 hook shipped together

Good fit It is for refreshing the documentation baseline, reviewing changes, detecting new documentation pages, and recommending schema or rule updates.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pdugan20/claudelint/check-upstream
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.

Any agent
npx skills add pdugan20/claudelint --skill check-upstream
Clone the repo
git clone --depth 1 https://github.com/pdugan20/claudelint

Made for: Claude Code, Codex.

Or install claudelint, the plugin that ships this one along with the rest of its 10 skills, 1 agent, 1 hook.

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 check-upstream

README.md
[![agentmods](https://agentmods.dev/badge/skills/pdugan20/claudelint/check-upstream/github.svg)](https://agentmods.dev/skills/pdugan20/claudelint/check-upstream)
Your own site
<a href="https://agentmods.dev/skills/pdugan20/claudelint/check-upstream"><img src="https://agentmods.dev/badge/skills/pdugan20/claudelint/check-upstream/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.

agentmods 80×15 button for check-upstream

Your own site · 80×15
<a href="https://agentmods.dev/skills/pdugan20/claudelint/check-upstream"><img src="https://agentmods.dev/badge/skills/pdugan20/claudelint/check-upstream.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 873 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00057 $0.00873
Opus 5 $0.00028 $0.00436
Sonnet 5 $0.00011 $0.00175
Haiku 4.5 $0.00006 $0.00087

Measured 9d ago against content hash e1c2345bd546, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

check-upstream 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 9d 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.

.agents/skills/check-upstream/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Check Upstream

Detects new Claude Code documentation surface and drift between the official docs and claudelint's schemas, then recommends concrete updates.

The deterministic half of this system runs in CI. This skill adds the judgment the scripts deliberately do not attempt: reading the prose diff and deciding what it means for claudelint.

Usage

Run this skill when asked to check for upstream changes, verify schemas are up to date, or find out what changed in Claude Code's documentation.

Step 1: Refresh the baseline

Run npm run upstream:refresh.

Watch for two things in the output:

  • [NEW PAGE] <slug> (NOT WATCHED ...) - a docs page appeared that claudelint does not watch. This is how a whole feature (such as plugin dependencies) arrives. Read the page and decide whether it belongs in src/upstream/watchlist.ts.
  • Extractor guard tripped - the extractor stopped finding facts on a page. Upstream changed format. Fix the extractor in scripts/upstream/extract.ts. Do NOT lower minFacts to make it pass; that disables the detector.

Step 2: Read the prose diff

Run git diff -- docs-baseline/.

This step is not optional, and it is not a skim. The scripts catch exactly two things: new pages, and hook-event drift. They do NOT catch field-level drift - a new, renamed, or removed field in any schema is caught ONLY by a human or agent reading this diff. They also cannot catch a constraint stated only in prose, and that class of change causes real bugs: the mintlify-docs install failure came from one sentence, "a bare string with only the plugin name".

So read the diff for both - changed fields and changed sentences. For each meaningful change, ask: does claudelint model this? Could a user violate it and have us report success?

Step 3: Run the conformance check

Run npm run check:upstream.

Its conformance findings cover hook events ONLY. A clean run means the HookEvents enum matches the baseline - it says nothing about whether any other field is up to date. Field drift is caught only by Step 2.

Read the full file on GitHub · 84 lines

Files

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.

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. 9d ago First seen · 84 lines · 57 tokens per session scan A e1c2345bd546

Subscribe to this mod's changes

check-upstream is a skill published in the GitHub repository pdugan20/claudelint (12 stars, last pushed today), licensed MIT. It adds 57 tokens to every session and 873 once invoked, about $0.0003 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.

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