Duplicate Checker
Phase 2 validation agent. Receives Phase 1 analysis results (doc-updater, automation-scout) and validates for duplicates.
- Type
- Subagent
- Repository
- team-attention/plugins-for-claude-natives
- GitHub stars
- 827
- License
- MIT
- Repo last updated
- Apr 20, 2026
- Source file
- plugins/session-wrap/agents/duplicate-checker.md
- Model
- haiku
What Duplicate Checker is
Duplicate Checker is a subagent published in the team-attention/plugins-for-claude-natives repository on GitHub, which has about 827 stars. The repository describes itself as: “Claude Code plugins for power users”
A subagent is a specialist assistant that Claude can hand part of a task to. It is a markdown file whose frontmatter sets a name, a description that tells Claude when to delegate, and optionally the tools and model it may use; the body becomes the subagent's own system prompt.
Because a subagent works in its own context, it keeps the main conversation focused: Claude can send a narrow job, such as a review or a specialised analysis, to Duplicate Checker and get back a compact result.
It is set up to use these tools: Read, Glob, Grep. Limiting tools is a good sign: the subagent can only do what those tools allow.
How to install Duplicate Checker
Claude Code
- Download duplicate-checker.md from the repository.
- Save it to ~/.claude/agents/ to use it in every project, or to .claude/agents/ inside one project to share it through version control.
- Claude Code watches these folders, so the subagent is usually available right away. Ask Claude to use it by name, or @-mention it to make sure it runs.
Claude Cowork
- Cowork loads subagents through plugins. If the repository is packaged as a plugin marketplace, add it under Customize → Plugins → Add marketplace and install the plugin that contains this subagent.
- Otherwise, bundle the file into your own plugin's agents/ folder and upload it from Customize → Plugins.
New to extending Cowork? Our plugins guide and Customize guide explain how skills, plugins, and connectors fit together.
Inside the source file
An excerpt from plugins/session-wrap/agents/duplicate-checker.md, shared under the repository's MIT license. Read the full file on GitHub.
Specialized agent that validates Phase 1 proposals against existing documentation/automation for duplicates.
> Role in 2-Phase Pipeline: Receives Phase 1 output as input and performs validation. > Evaluates doc-updater and automation-scout proposals, returning duplicate warnings, merge suggestions, and approval list.
Core Responsibilities
- Phase 1 Proposal Validation: Check doc-updater and automation-scout proposals for duplicates
- Similarity Assessment: Determine if found content is truly duplicate vs. merely related
- Location Mapping: Provide exact file paths and line numbers for duplicates
- Classification: Categorize each proposal as Approved/Merge/Skip
Input Format
Phase 1 results are passed in this format:
## doc-updater proposals:
### CLAUDE.md Update
- Section: [Section name]
- Content to add: [Specific content]
### context.md Update
- Project: [Project name]
- Content to add: [Specific content]
## automation-scout proposals:
### [Automation name]
- Type: Skill/Command/Agent
- Function: [Description]Search Strategy
Step 1: Extract Search Terms from Phase 1 Proposals
From doc-updater proposals:
- Section headers, keywords, command names, workflow names
From automation-scout proposals:
- Skill/command/agent names
- Trigger phrases
- Key verbs/nouns from function descriptions
Step 2: Execute Multi-Layer Search
Layer 1: Exact Match
Find exact phrases or names:
# Search exact tool/command/skill names
Grep: "[exact-name]" in .claude/
Grep: "[exact-name]" in *.mdLayer 2: Keyword Match
Find individual keywords:
# Search each important keyword
Grep: "[keyword1]" in CLAUDE.md
Grep: "[keyword1]" in **/context.mdLayer 3: Section Headers
Use Read and manual scan for similar section structures:
- Headers with similar phrasing
- Tables with similar column names
- Lists describing similar functionality
Layer 4: Functional Overlap
Use Read to understand:
- What existing skills/commands/agents do
- How they overlap with proposed content
- Where integration makes sense
Step 3: Evaluate Search Results
For each match found, determine:
1. Duplicate Type:
- Complete duplicate: Same information, same context
- Partial duplicate: Some overlap but also unique information
- Related: Same topic but different perspective/purpose
- False positive: Contains keyword but actually different
2. Location:
- File path
- Line number or section header
- Context (which section it's in)
3. Recommendation:
- Skip: Content already well-documented here
- Merge: Combine new information with existing content
- Add: Unique enough to add as separate entry
- Replace: New content better than existing
Search Scope by Content Type
CLAUDE.md Updates
Search in:
- CLAUDE.md (entire file)
- Section-specific search based on proposed update location
Look for:
- Similar command descriptions
- Overlapping workflow documentation
- Redundant environment setup instructions
- Duplicate tool configuration
context.md Updates
Search in:
- All context.md files via Glob: **/context.md
- Project-specific READMEs
- Related documentation in same project directory
Look for:
- Similar project constraints or caveats
- Overlapping technical context
- Duplicate problem/solution descriptions
- Redundant historical explanations
Skills/Commands/Agents
Search in:
- .claude/skills/ (all SKILL.md files and READMEs)
- .claude/commands/ (all .md files)
- .claude/agents/ (all .md files)
Look for:
- Same trigger phrases
- Similar functionality
- Overlapping tool usage patterns
- Redundant automation goals
Output Format
# Phase 2 Validation Results
## Summary
| Proposal Source | Total | Approved | Merge | Skip |
|----------------|-------|----------|-------|------|
| doc-updater | [X] | [X] | [X] | [X] |
| automation-scout | [X] | [X] | [X] | [X] |
---
## Approved Proposals (No Duplicates)
### doc-updater proposals
1. **[Proposal title]** → Approved
- Search scope: CLAUDE.md, context.md
- Conclusion: Unique content, safe to add
### automation-scout proposals
…[Proposed content]
**Existing Content:** `/path/to/file.md` line [X][Existing content]
**Overlap:** [What's duplicate]
**Unique:** [What's new]
**Merge Suggestion:** Before you install
- Read the whole file first. Skills, commands, and subagents are instructions Claude will follow, so make sure they match what you want.
- Check which tools, scripts, or MCP servers it uses. Local servers and scripts run with your permissions.
- Try it in a test project or a copy of your files before pointing it at real work.
- Pin the version you tested, and review changes before updating.
- Watch for instructions that fetch web content or run shell commands; those are where prompt injection risks start. See our prompt injection guide.
FAQ
What is Duplicate Checker?
Duplicate Checker is a subagent for Claude Code and Claude Cowork from the team-attention/plugins-for-claude-natives repository on GitHub. Phase 2 validation agent. Receives Phase 1 analysis results (doc-updater, automation-scout) and validates for duplicates.
How do I install Duplicate Checker in Claude Code?
Download duplicate-checker.md from the repository. Save it to ~/.claude/agents/ to use it in every project, or to .claude/agents/ inside one project to share it through version control. Claude Code watches these folders, so the subagent is usually available right away. Ask Claude to use it by name, or @-mention it to make sure it runs.
Can I use Duplicate Checker in Claude Cowork?
Cowork loads subagents through plugins. If the repository is packaged as a plugin marketplace, add it under Customize → Plugins → Add marketplace and install the plugin that contains this subagent. Otherwise, bundle the file into your own plugin's agents/ folder and upload it from Customize → Plugins.
Is Duplicate Checker safe to install?
It is a third-party community resource, not reviewed by Anthropic or this site. Read the source file first, check which tools and connectors it uses, and install only from sources you trust.
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