Classify and Filter Your Knowledge

Add tags to documents for instant filtering. Automatic frontmatter extraction, hierarchical tags, and powerful AND/OR filters across CLI, Web UI, and MCP.

Key Benefits

  • Auto-extract from frontmatter
  • Hierarchical tags (project/api, status/review)
  • Filter with --tags-any (OR) or --tags-all (AND)
  • Tag autocomplete in Web UI
  • Write-back to markdown frontmatter
  • MCP tools for AI agents

Example Commands

gno search 'query' --tags-any bug,feature gno query 'topic' --tags-all status/active gno tag set doc.md api,v2

Get Started

Ready to try Tag System?

Quick Start Guide CLI Reference

What Are Tags?

Tags let you classify documents beyond their content. Filter search results by status, project, topic, or any category you define. GNO extracts tags automatically from markdown frontmatter.

---
title: API Design Doc
tags:
  - project/api
  - status/review
  - priority/high
---

Automatic Extraction

GNO reads tags from markdown frontmatter during indexing. No manual tagging required if your documents already have frontmatter.

Supported formats:

# Array format
tags: [api, v2, internal]

# List format
tags:
  - api
  - v2
  - internal

Hierarchical Tags

Use / to create tag hierarchies:

  • project/api, project/frontend, project/infra
  • status/draft, status/review, status/published
  • team/backend, team/design

Hierarchical tags enable precise filtering while keeping related concepts grouped.

Filtering Search Results

Match Any Tag (OR)

gno search "authentication" --tags-any bug,feature

Returns documents tagged with bug OR feature.

Match All Tags (AND)

gno query "API design" --tags-all status/review,priority/high

Returns only documents tagged with BOTH status/review AND priority/high.

Combine with Collections

gno search "migration" -c work --tags-any urgent

Managing Tags

View Document Tags

gno tag get path/to/document.md

Set Tags

gno tag set path/to/document.md api,v2,internal

For markdown files, GNO writes tags back to frontmatter.

List All Tags

gno tag list
gno tag list --json

Shows all tags in your index with document counts.

Web UI

The Web UI provides visual tag management:

Tag Autocomplete

When editing documents, the tag input shows suggestions from existing tags as you type.

The search sidebar shows tag facets - click any tag to filter results instantly.

Filter Chips

Active tag filters appear as removable chips above search results.

MCP Integration

AI agents can filter searches by tags:

{
  "tool": "gno_query",
  "arguments": {
    "query": "authentication flow",
    "tags_any": ["api", "security"]
  }
}

Available MCP tag tools:

Tool Description
gno_tag_list List all tags with counts
gno_tag_get Get tags for a document
gno_tag_set Set tags on a document
gno_tag_add Add tags to existing
gno_tag_remove Remove specific tags

Use Cases

  • Status tracking: status/draft, status/review, status/published
  • Project organization: project/api, project/mobile, project/infra
  • Priority management: priority/urgent, priority/backlog
  • Content types: type/spec, type/meeting, type/decision
  • Teams: team/backend, team/design, team/product

Getting Started

# Index documents with existing frontmatter tags
gno update

# List extracted tags
gno tag list

# Search with tag filter
gno search "topic" --tags-any project/api