did-ai-write-this

A text-checking skill that sends writing to Pangram's version 3 AI-detection service and returns a structured assessment of whether it may be AI-generated.

In plain words
What is it for?
Checking short text or longer documents for AI authorship, with a label and three probability fractions that add up to 1.
Why use it?
It provides a service-based check when someone asks whether text was written by AI, instead of relying on guesses from writing style.

Skill for Claude CodeCodex

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/asteroidhunter/did-ai-write-this/src
Any agent
npx skills add AsteroidHunter/did-ai-write-this --skill src
Clone the repo
git clone --depth 1 https://github.com/AsteroidHunter/did-ai-write-this

Made for: Claude Code, Codex.

Per session 226 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,316 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 $0.00226 $0.01316
Opus 5 $0.00113 $0.00658
Sonnet 5 $0.00045 $0.00263
Haiku 4.5 $0.00023 $0.00132

Measured 2d ago against content hash 51e2e466ac07, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

did-ai-write-this 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 2d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (cli.py, core.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

src/SKILL.md · 79 lines

How it starts

The opening of the file, as written. The whole thing — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.

When to use

  • Direct user request — the user pastes text and asks whether it was AI-written, or any phrasing of that question ("is this AI?", "did ChatGPT write this?", "human or AI?", etc.). This is the only auto-trigger case.
  • Proactive post-WebFetch check (opt-in only) — skipped by default because every call costs the user a Pangram credit. If the user has added an instruction to their CLAUDE.md along the lines of "when researching, run did-ai-write-this on WebFetch'd pages before citing", honor that. Otherwise wait for an explicit ask — do not call this skill on every WebFetch.
  • Not for stylistic AI-detection guesses based on writing patterns — those are unreliable and this skill exists precisely to replace them with a calibrated, vendor-backed signal.

How to invoke

The CLI sits next to this SKILL.md and runs inside a self-contained venv populated by install.py. Always invoke through ${CLAUDE_SKILL_DIR} so the path works regardless of where the skill is installed.

Positional argument (short snippet, one shot):

${CLAUDE_SKILL_DIR}/.venv/bin/python ${CLAUDE_SKILL_DIR}/cli.py "the text to check"

From a file (longer documents):

${CLAUDE_SKILL_DIR}/.venv/bin/python ${CLAUDE_SKILL_DIR}/cli.py --file /path/to/document.txt

From stdin (piping output of another command, common for WebFetch content saved to a temp file or var):

cat /tmp/fetched.txt | ${CLAUDE_SKILL_DIR}/.venv/bin/python ${CLAUDE_SKILL_DIR}/cli.py --stdin

Per-paragraph attribution for mixed documents — adds a windows array showing which segments drove the overall label:

${CLAUDE_SKILL_DIR}/.venv/bin/python ${CLAUDE_SKILL_DIR}/cli.py --full --file /path/to/mixed_doc.txt

Force the output format if needed: --json (always JSON) or --pretty (always one-line summary). Default behavior is JSON when stdout is captured (your Bash tool case) and pretty when stdout is a terminal (user case), so the flags are usually unnecessary.

Read the full file on GitHub · 79 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.

  1. 2d ago First seen · 79 lines · 226 tokens per session scan A 51e2e466ac07

Subscribe to this mod's changes

did-ai-write-this is a skill published in the GitHub repository AsteroidHunter/did-ai-write-this (2 stars, last pushed 3mo ago), licensed MIT. It adds 226 tokens to every session and 1,316 once invoked, about $0.0011 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 2026-08-31.

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