Check Duplicates

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).
• gh CLI 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 "" --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 .

---

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

Check if the issue is already assigned or has an in-progress label. If someone else is working on it, inform the user before proceeding.

5. Report results

If no duplicates, no existing PRs, and no assignment conflicts are found, report that the issue is clear to work on. Do not post a comment on the issue in this case.

Outcome

| Finding | Action | |---|---| | Duplicate issue found | Comment on current issue linking to duplicate, stop | | Existing fix PR found | Inform user, offer to review, stop | | Someone already assigned | Inform user, let them decide whether to proceed | | No conflicts | Issue is clear to work on, proceed |

If $OUTCOME_YAML is set, also emit your routing verdict there per skills/sdlc/references/shared.md:

| Verdict | When | |---|---| | novel | No conflicts, issue is clear to work on | | duplicate | Duplicate issue or existing fix PR found |

Example Usage

Scenario 1: Duplicate found

/check-duplicates 20 owner/myrepo

Finds issue #12 describes the same bug. Comments on #20 linking to #12.

Scenario 2: Existing PR found

/check-duplicates 30 owner/myrepo

Finds PR #45 already references issue #30. Informs user and offers to review.

Scenario 3: Clear to work on

/check-duplicates 42 owner/myrepo

No duplicates, no existing PRs, no assignment conflicts. Reports clear.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: tomzx
• Source: tomzx/agents
• License: MIT

Install and usage instructions live in the source repository linked above.