Opus 4.6 Capabilities

Opus 4.6 Capabilities

Claude Opus 4.6 brings transformative capabilities to the Claude Copilot framework with a 1M token context window and adaptive thinking.

Overview

Claude Opus 4.6 represents a significant leap in model capabilities:

What Changed in Claude Copilot

The framework has been modernized to leverage Opus 4.6 capabilities while maintaining backward compatibility.

1. Effort Parameter Replaces Model Selection

Previous approach (legacy): Tasks routed to different models (haiku/sonnet/opus) based on complexity.

New approach (Opus 4.6): All tasks use Opus 4.6 with varying effort levels.

Code example:

// Effort-based routing (Opus 4.6)
import { routeToModel } from 'ecomode/model-router';

const result = routeToModel({
  title: 'Design authentication architecture',
  fileCount: 10,
  agentId: 'ta'
});

// result.route.effortLevel = 'max' (high complexity detected)
// result.route.model = 'opus' (Opus 4.6)

Complexity-to-Effort Mapping:

Note: medium effort is reserved for future use or explicit overrides.

2. Magic Keyword Changes (Breaking)

Magic keywords now control effort levels instead of model selection.

Breaking change:

Migration guide:

# Old (legacy):
/protocol fast: fix the login bug
# → Routed to Haiku model

# New (Opus 4.6):
/protocol fast: fix the login bug
# → Opus 4.6 with effort: medium

# To get truly fast execution with low effort:
/protocol eco: fix the login bug
# → Opus 4.6 with effort: low

All keywords:

eco:     → effort: low (cost-optimized, minimal thinking)
fast:    → effort: medium (balanced speed and quality)
max:     → effort: max (deep reasoning, highest quality)

Model-specific keywords removed: opus:, sonnet:, haiku: are deprecated. All tasks use Opus 4.6 with varying effort.

3. Relaxed Main Session Guardrails

Context limits increased to leverage 1M token window.

File read limits:

Token budgets:

Compaction thresholds:

Agent handoff limits:

CRITICAL vs. SHOULD rules:

Main session guardrails now split into two tiers:

What You MUST NEVER Do:

• Write implementation code (delegate to @agent-me)
• Create detailed plans (delegate to @agent-ta)
• Use generic agents (Explore, Plan, general-purpose)

What You SHOULD AVOID:

• Read more than 8 files (prefer delegation for large exploration)
• Return detailed analysis (store as work product)

4. Ecomode Model Router Refactor

The Ecomode model router has been refactored to separate effort selection from model routing.

Old architecture:

Task → Complexity Score → Model (haiku/sonnet/opus)

New architecture (Opus 4.6):

Task → Complexity Score → Effort Level (low/medium/high/max)
                        → Model (always opus for complex tasks)

Type changes:

// New type: EffortLevel
type EffortLevel = 'low' | 'medium' | 'high' | 'max';

// ModelRoute now includes effort
interface ModelRoute {
  model: 'haiku' | 'sonnet' | 'opus';
  confidence: number;
  reason: string;
  isOverride: boolean;
  costTier: 'low' | 'medium' | 'high';
  effortLevel: EffortLevel;  // NEW
}

Key files:

• ecomode/model-router.ts - Routing logic with effort parameter
• ecomode/complexity-scorer.ts - Unchanged (complexity scoring)
• types/omc-features.ts - Type definitions

Agent Teams Coexistence Strategy

Opus 4.6 introduces experimental Agent Teams for multi-agent orchestration. How does this relate to Claude Copilot's orchestration?

Recommendation: COEXIST

Claude Copilot orchestration and Agent Teams serve different use cases.

When to Use Agent Teams

Ideal scenarios:

# Quick exploration without formal tracking
"@agent-ta and @agent-sec, review this API endpoint for security issues"

# Rapid prototyping
"@agent-uxd and @agent-uids, sketch out a new dashboard layout"

# One-off analysis
"@agent-qa and @agent-me, debug why tests are failing"

Benefits:

• No PRD or task creation needed
• Agents coordinate naturally through conversation
• Fast setup, minimal overhead
• Good for throwaway work

Limitations:

• No persistent work products
• No progress tracking across sessions
• No quality gates or validation
• Hard to resume after interruptions

When to Use Claude Copilot Orchestration

Ideal scenarios:

# Multi-stream initiative with deliverables
/orchestrate generate
/orchestrate start

# Work that needs recovery across sessions
/continue Stream-B

# Production code with quality requirements
# (uses quality gates, git worktrees, validation)

# Work requiring audit trail
# (all decisions, work products, and progress tracked)

Benefits:

• Persistent memory and work products
• Stream isolation with git worktrees
• Quality gates and validation
• Progress tracking and recovery
• Audit trail of all decisions

Trade-offs:

• More setup (PRD creation)
• Framework learning curve
• Overhead for simple tasks

Hybrid Approach

Use both systems together:

# 1. Explore with Agent Teams (fast, informal)
"@agent-ta and @agent-sd, brainstorm authentication approaches"

# 2. Formalize with Claude Copilot (structured, tracked)
/protocol implement OAuth2 authentication
# → Creates PRD, tasks, work products, quality gates

Pattern: Agent Teams for discovery, Claude Copilot for delivery.

Migration Guide

Migrating existing workflows to leverage Opus 4.6 capabilities.

For Framework Users

No action required. The framework maintains backward compatibility:

• Magic keywords (eco:, fast:, max:) work automatically
• Existing agents route to Opus 4.6 with appropriate effort levels
• Token budgets adjusted automatically
• All tools and protocols unchanged

Optional optimizations:

1. Use effort keywords explicitly:

   # Old: rely on auto-detection
   /protocol fix the login bug
   
   # New: explicit effort control
   /protocol eco: fix the login bug  # Low effort, fast
   /protocol max: design auth system # Max effort, deep thinking
   

2. Leverage larger context:

   # Old: delegate to avoid reading many files
   /protocol analyze the codebase
   
   # New: main session can read more
   # (Still delegate for >8 files, but less strict)
   

3. Create larger work products:

   # Compaction threshold now 13,927 tokens (was 3,482)
   # Agents can return more detailed summaries before compacting
   

For Framework Developers

Required changes:

1. Update agent model references:

   # Old (.claude/agents/ta.md)
   model: opus
   
   # New (optional, defaults to opus)
   model: opus  # All agents use Opus 4.6
   

2. Remove model-specific overrides:

   # Old: Force specific model
   tc task create --title "..." --prd <id> --json
   # metadata: { modelOverride: 'haiku' }
   
   # New: Use effort levels
   tc task create --title "..." --prd <id> --json
   # metadata: { effortOverride: 'low' }  -- Future enhancement
   

3. Update keyword documentation:

   • Remove references to model-specific keywords (opus:, sonnet:, haiku:)
   • Document effort keywords (eco:, fast:, max:)
   • Update magic-keywords.md examples

Optional enhancements:

1. Adjust compaction thresholds:

   // Old: 4,096 tokens
   const threshold = 4096;
   
   // New: 16,384 tokens (4x larger)
   const threshold = 16384;
   

2. Increase token budgets:

   • Agent response summaries: 100 → 400 tokens
   • Work product summaries: 500 → 2,000 tokens
   • Initiative summaries: 2,000 → 8,000 tokens

3. Relax file read warnings:

   # Old
   **NEVER read more than 3 files**
   
   # New
   **SHOULD AVOID reading more than 8 files**
   

Performance Implications

How Opus 4.6 changes framework performance and cost.

Token Efficiency

Net impact: Slightly higher token usage, but better quality and larger context reduces iterations.

Cost Considerations

Effort levels impact cost through token usage:

Cost optimization strategies:

1. Use eco: keyword for simple tasks:

   /protocol eco: fix typo in README
   # → effort: low (minimal tokens)
   

2. Reserve max: for critical work:

   /protocol max: design payment processing architecture
   # → effort: max (deep reasoning needed)
   

3. Default to high for standard tasks:

   /protocol implement user profile feature
   # → effort: high (auto-detected from complexity)
   

Context Compaction

Native compaction API: Opus 4.6 includes automatic context management.

Framework integration (future):

// Current: Manual compaction at 85% threshold
if (tokens > 13927) {
  compactAndStore();
}

// Future: Leverage native compaction API
const response = await claude.messages.create({
  context_compaction: {
    enabled: true,
    threshold: 0.85
  }
});

Benefits:

• Automatic context management
• No manual token counting
• Better preservation of important context

Future Enhancements

Planned improvements leveraging Opus 4.6 capabilities.

1. Native Compaction Integration

Replace manual compaction with Opus 4.6's native API.

Implementation:

• Remove custom compaction logic
• Use Claude Messages API context_compaction parameter
• Automatic threshold management

Timeline: Q2 2026

2. Effort-Level Task Metadata

Store effort level in task metadata for better tracking.

tc task create --title "Complex refactor" --prd <id> --json
# metadata: { effortOverride: 'max', estimatedEffort: 'high' }

Benefits:

• Explicit effort control per task
• Track actual effort vs. estimated
• Better cost forecasting

Timeline: Q2 2026

3. Agent Teams Hybrid Mode

Combine Agent Teams with Claude Copilot orchestration.

Use case:

# Phase 1: Explore with Agent Teams
"@agent-ta and @agent-sec, design authentication approach"

# Phase 2: Formalize discoveries in PRD
/protocol implement OAuth2 authentication
# → Uses Agent Teams discoveries as context

Implementation:

• Convert Agent Teams conversations to work products
• Auto-link to PRD context
• Preserve collaborative decisions

Timeline: Q3 2026

4. Dynamic Effort Adjustment

Automatically adjust effort mid-task based on complexity signals.

Example:

// Task starts with effort: high
// Agent encounters unexpected complexity
// System auto-escalates to effort: max
// Agent continues with deeper reasoning

Benefits:

• Better handling of unexpected complexity
• No manual intervention needed
• Optimal effort allocation

Timeline: Q4 2026

FAQ

Q: Do I need to change anything to use Opus 4.6?

A: No. The framework automatically uses Opus 4.6 with appropriate effort levels. Existing workflows continue unchanged.

Q: What happened to haiku and sonnet models?

A: They're still supported for backward compatibility, but the framework now prefers Opus 4.6 with varying effort levels for better quality and consistency.

Q: How do I control cost with Opus 4.6?

A: Use the eco: keyword for simple tasks (effort: low), which minimizes token usage. Reserve max: for complex work requiring deep reasoning.

Q: Can I still use fast: keyword?

A: Yes, but it now maps to effort: medium instead of forcing Haiku model. For truly fast execution, use eco: (effort: low).

Q: Should I use Agent Teams or Claude Copilot orchestration?

A: Use Agent Teams for quick exploration and ad-hoc collaboration. Use Claude Copilot orchestration for structured initiatives requiring tracking, quality gates, and recovery.

Q: What's the performance impact of Opus 4.6?

A: Token usage may increase 25-33% compared to using haiku/sonnet for simple tasks, but better quality often reduces iterations, leading to net savings.

Q: How do I migrate existing tasks?

A: No migration needed. Existing tasks continue working. Future tasks automatically use Opus 4.6 with effort levels.

Q: Can I force a specific model instead of effort levels?

A: Model-specific keywords are deprecated. Use effort levels instead. If you need model control for testing, use task metadata: { modelOverride: 'opus' }.

Related Documentation

• Ecomode - Complexity scoring and model routing details
• Magic Keywords - Effort and action keyword reference
• Main Session Guardrails - Updated token limits
• Enhancement Features - Auto-compaction thresholds
• Agent Guide - Agent-specific patterns

Summary

Opus 4.6 transforms Claude Copilot with:

Migration: Zero action required. Framework automatically leverages Opus 4.6 capabilities while maintaining backward compatibility.

Cost optimization: Use eco: for simple tasks, max: for critical work, default high for everything else.