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.
npx agentmods add skills/tomzx/agents/check-duplicatesnpx skills add tomzx/agents --skill check-duplicatesgit clone --depth 1 https://github.com/tomzx/agentsWrote 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.
[](https://agentmods.dev/skills/tomzx/agents/check-duplicates)<a href="https://agentmods.dev/skills/tomzx/agents/check-duplicates"><img src="https://agentmods.dev/badge/skills/tomzx/agents/check-duplicates.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00021 | $0.00897 |
| Opus 5 | $0.00010 | $0.00449 |
| Sonnet 5 | $0.00004 | $0.00179 |
| Haiku 4.5 | $0.00002 | $0.00090 |
Grade A, and why
check-duplicates 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 4d 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.
How it starts
The opening of the file, as written. The whole thing — 124 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Check Duplicates
Checks a GitHub issue for duplicate issues and existing fix PRs. Use before starting work on any issue to avoid wasted effort.
This skill performs read-only checks and posts a comment only if a duplicate is found. It does not modify the issue or create any branches.
Prerequisites
- Apply the shared SDLC conventions in
skills/sdlc/references/shared.md. - If no argument is provided, target the issue from
$ISSUE_NUMBER(and$REPO). ghCLI authenticated with read access to the target repository- A GitHub issue number to check
Skill attribution (GitHub)
If posting a comment about a duplicate, read ../github-post-attribution/SKILL.md and append the footer for SKILL_DIR = check-duplicates.
Steps
1. Fetch the issue
Fetch the issue details to extract search keywords:
ghx issue view $ISSUE_NUMBER --repo $REPO
Extract keywords from:
- Title
- Error messages or stack traces
- Key nouns describing the affected component or behavior
2. Search for duplicate issues
Using 2-3 different keyword combinations, search for similar open and closed issues:
ghx issue list --repo $REPO --search "<keywords>" --state all --limit 10
Exclude the current issue from results. For each candidate, compare:
- Whether it describes the same root cause or behavior
- Whether it is still open (closed may indicate a previous fix)
- Whether it covers the same scope or a subset
If a duplicate is found, comment on the current issue and stop:
gh issue comment $ISSUE_NUMBER --repo $REPO --body "$(cat <<'EOF'
Duplicate of #<existing-issue-number>.
---
Posted with [check-duplicates](SKILL_FILE_URL) (`SKILL_SHORT_SHA`)
EOF
)"
3. Check for existing fix PRs
Search for open PRs that reference this issue:
ghx pr list --repo $REPO --search "$ISSUE_NUMBER" --state open --limit 10
If a fix PR already exists, inform the user and stop. Optionally offer to review it with /review-pr.
4. Check assignment and status
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.
- 4d ago First seen · 124 lines · 21 tokens per session scan A 7adcc65b8229
check-duplicates is a skill published in the GitHub repository tomzx/agents (6 stars, last pushed today), licensed MIT. It adds 21 tokens to every session and 897 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 2026-08-31.
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