local-cal/.opencode/context/core/context-system.md

Context System

Purpose: Minimal, concern-based knowledge organization for AI agents

Last Updated: 2026-01-08

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Core Principles

1. Minimal Viable Information (MVI)

Extract only core concepts (1-3 sentences), key points (3-5 bullets), minimal example, and reference link. Goal: Scannable in <30 seconds. Reference full docs, don't duplicate them.

2. Concern-Based Structure

Organize by what you're doing (concern), then by how you're doing it (approach/tech):

Two organizational patterns:

Pattern A: Function-Based (for repository-specific context)

category/
├── navigation.md
├── concepts/              # What it is
├── examples/              # Working code
├── guides/                # How to do it
├── lookup/                # Quick reference
└── errors/                # Common issues

Use when: Content is repository-specific (e.g., openagents-repo/)

Pattern B: Concern-Based (for development context)

category/
├── navigation.md
├── {concern}/             # Organize by what you're doing
│   ├── navigation.md
│   ├── {approach}/        # Then by approach/tech
│   │   ├── navigation.md
│   │   └── {files}.md

Use when: Content spans multiple technologies (e.g., development/)

Examples:

• development/backend/api-patterns/ - Concern: backend, Approach: API patterns
• development/backend/nodejs/ - Concern: backend, Tech: Node.js
• development/frontend/react/ - Concern: frontend, Tech: React

3. Token-Efficient Navigation

Every category/subcategory has navigation.md with:

• ASCII tree for quick structure scan (~50 tokens)
• Quick routes table for common tasks (~100 tokens)
• By concern/type sections (~50 tokens)
• Total: ~200-300 tokens per navigation file

Why: Faster loading, less cost, quicker AI decisions

4. Specialized Navigation Files

For cross-cutting concerns, create specialized navigation:

• development/ui-navigation.md - Spans frontend/ + ui/
• development/backend-navigation.md - Covers APIs, auth, middleware
• development/fullstack-navigation.md - Common tech stacks

Why: Real workflows don't fit neat categories

5. Self-Describing Filenames

Filenames should tell you what's inside:

• ❌ code.md → ✅ code-quality.md
• ❌ tests.md → ✅ test-coverage.md
• ❌ review.md → ✅ code-review.md

Why: No need to open files to understand content

6. Knowledge Harvesting

Extract valuable context from AI summaries/overviews, then delete them. Workspace stays clean, knowledge persists.

5. Technology Context Organization

Purpose: Ensure consistent placement of new technologies (frameworks, libraries, tools) to maintain discoverability.

Frameworks vs Architectural Layers:

• Full-Stack Frameworks (e.g., Tanstack Start, Next.js): Add under development/frameworks/{tech}/. These are "meta-frameworks" that span multiple layers.
• Specialized Concerns (e.g., AI, Data): Add under development/{concern}/{tech}/.
• Layer-Specific Tech (e.g., React, Node.js): Add under development/{frontend|backend}/{tech}/.

Decision Process:

1. Is it a full-stack framework? → development/frameworks/
2. Is it a specialized domain (AI, Data)? → development/{domain}/
3. Is it layer-specific? → development/{frontend|backend}/

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Directory Patterns

Pattern A: Function-Based (Repository-Specific)

Use for: Repository-specific context (e.g., openagents-repo/)

.opencode/context/{category}/
├── navigation.md              # Fast, token-efficient navigation
├── quick-start.md             # Optional: 2-minute orientation
│
├── core-concepts/             # Foundational concepts (optional)
│   ├── navigation.md
│   └── {concept}.md
│
├── concepts/                  # What it is
│   ├── navigation.md
│   └── {concept}.md
│
├── examples/                  # Working code
│   ├── navigation.md
│   └── {example}.md
│
├── guides/                    # How to do it
│   ├── navigation.md
│   └── {guide}.md
│
├── lookup/                    # Quick reference
│   ├── navigation.md
│   └── {lookup}.md
│
└── errors/                    # Common issues
    ├── navigation.md
    └── {error}.md

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Pattern B: Concern-Based (Development Context)

Use for: Multi-technology development context (e.g., development/)

.opencode/context/{category}/
├── navigation.md                       # Main navigation
├── {concern}-navigation.md             # Specialized navigation (optional)
│
├── principles/                         # Universal principles (optional)
│   ├── navigation.md
│   └── {principle}.md
│
├── {concern}/                          # Organize by concern
│   ├── navigation.md
│   │
│   ├── {approach}/                     # Then by approach
│   │   ├── navigation.md
│   │   └── {pattern}.md
│   │
│   └── {tech}/                         # Or by tech
│       ├── navigation.md
│       └── {pattern}.md

Example:

development/
├── navigation.md
├── ui-navigation.md                    # Specialized
├── backend-navigation.md               # Specialized
├── fullstack-navigation.md             # Specialized
│
├── principles/                         # Universal
│   ├── clean-code.md
│   └── api-design.md
│
├── frontend/                           # Concern
│   ├── react/                          # Tech
│   │   ├── hooks-patterns.md
│   │   └── tanstack/                   # Sub-tech
│   │       ├── query-patterns.md
│   │       └── router-patterns.md
│   └── vue/                            # Tech
│
├── backend/                            # Concern
│   ├── api-patterns/                   # Approach
│   │   ├── rest-design.md
│   │   └── graphql-design.md
│   ├── nodejs/                         # Tech
│   └── authentication/                 # Functional concern
│
└── data/                               # Concern
    ├── sql-patterns/                   # Approach
    └── orm-patterns/                   # Approach

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Navigation File Format

Token-Efficient Template

# {Category} Navigation

**Purpose**: [1 sentence]

---

## Structure

{category}/ ├── navigation.md ├── {subcategory}/ │ ├── navigation.md │ └── {files}.md

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## Quick Routes

| Task | Path |
|------|------|
| **{Task 1}** | `{path}` |
| **{Task 2}** | `{path}` |

---

## By {Concern/Type}

**{Section 1}** → {description}
**{Section 2}** → {description}

Target: 200-300 tokens

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Organizing Principles

1. Core Standards (Universal)

Location: .opencode/context/core/standards/

Purpose: Universal standards that apply to ALL development

Content:

• Code quality principles (all languages)
• Test coverage standards
• Documentation standards
• Security patterns
• Code analysis approaches

Used by: All agents, all projects

Effect on other categories:

• Other categories can reference these standards
• Users can edit core standards to affect context flow globally
• Development-specific standards go in development/principles/

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2. Development Principles vs Core Standards

Location	Scope	Examples
core/standards/	Universal (all projects, all languages)	Code quality, testing, docs, security
development/principles/	Development-specific (software engineering)	Clean code, API design, error handling

Both exist: Core standards are universal, development principles are domain-specific

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3. Data Context Location

Decision: Data patterns live in development/data/ (not top-level)

Rationale: Data layer is part of development workflow

Structure:

development/data/
├── navigation.md
├── sql-patterns/
├── nosql-patterns/
└── orm-patterns/

Top-level data/ category: Reserved for data engineering/analytics (different concern)

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4. Specialized Navigation Strategy

Full-stack navigation includes:

• Quick routes (table format)
• Common stack patterns (MERN, T3, etc.)

Example:

## Quick Routes
| Task | Path |
|------|------|
| **Frontend** | `ui-navigation.md` |

## Common Stacks

### MERN Stack
Frontend: development/frontend/react/
Backend:  development/backend/nodejs/
Data:     development/data/nosql-patterns/mongodb.md

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Operations

Harvest (/context harvest)

Purpose: Extract knowledge from summary files → permanent context, then clean up.

Process:

1. Scan for patterns: *OVERVIEW.md, *SUMMARY.md, SESSION-*.md, CONTEXT-*.md
2. Analyze content:
   • Design decisions → concepts/
   • Solutions/patterns → examples/
   • Workflows → guides/
   • Errors encountered → errors/
   • Reference data → lookup/
3. Present approval UI (letter-based: A B C or all)
4. Extract + minimize (apply MVI)
5. Archive/delete summaries
6. Report results

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Extract (/context extract)

Purpose: Extract context from docs/code/URLs.

Process:

1. Read source
2. Extract core concepts (1-3 sentences each)
3. Find minimal examples
4. Identify workflows (numbered steps)
5. Build lookup tables
6. Capture errors/gotchas
7. Create references

Output: Follow MVI template

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Organize (/context organize)

Purpose: Restructure existing files into appropriate pattern.

Process:

1. Scan category
2. Determine pattern (function-based or concern-based)
3. Create missing directories
4. Move/refactor files
5. Update navigation.md
6. Fix references

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Update (/context update)

Purpose: Update context when APIs/frameworks change.

Process:

1. Identify what changed
2. Find affected files
3. Update concepts, examples, guides, lookups
4. Add migration notes to errors/
5. Validate references

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File Naming Conventions

Navigation Files

• navigation.md - Main navigation for category/subcategory
• {domain}-navigation.md - Specialized cross-cutting navigation

Content Files

• Use descriptive names: code-quality.md not code.md
• Include type when helpful: rest-design.md, jwt-patterns.md
• Use kebab-case: scroll-linked-animations.md

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Extraction Rules

✅ Extract:

• Core concepts (minimal)
• Essential patterns
• Step-by-step workflows
• Critical errors
• Quick reference data
• Links to detailed docs

❌ Don't Extract:

• Verbose explanations
• Complete API docs
• Implementation details
• Historical context
• Marketing content
• Duplicate info

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Success Criteria

✅ Minimal - Core info only, <200 lines per file ✅ Navigable - navigation.md at every level ✅ Organized - Appropriate pattern (function-based or concern-based) ✅ Token-efficient - Navigation files ~200-300 tokens ✅ Self-describing - Filenames tell you what's inside ✅ Referenceable - Links to full docs ✅ Searchable - Easy to find via navigation ✅ Maintainable - Easy to update

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Related Documentation

• context-system/guides/navigation-design.md - How to create navigation files
• context-system/guides/organizing-context.md - How to choose organizational pattern
• context-system/examples/navigation-examples.md - Good navigation examples
• context-system/standards/templates.md - File templates

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Quick Commands

/context                      # Quick scan, suggest actions
/context harvest              # Clean up summaries → permanent context
/context extract {source}     # From docs/code/URLs
/context organize {category}  # Restructure flat files → function folders
/context update {what}        # When APIs/frameworks change
/context migrate              # Move global project-intelligence → local project
/context create {category}    # Create new context category
/context error {error}        # Add recurring error to knowledge base
/context compact {file}       # Minimize verbose file to MVI format
/context map [category]       # View context structure
/context validate             # Check integrity, references, sizes

All operations show a preview of what will be created/moved/deleted before asking for approval.