opus-extended-thinking

name	opus-extended-thinking
description	Use Claude's extended/adaptive thinking for deep reasoning, complex analysis, and multi-step synthesis — both the prompt patterns that elicit deliberation and the current thinking API (adaptive thinking + the effort parameter). Use when a problem needs thorough deliberation before answering, or when configuring thinking on a Claude request.
version	2.0.0
last_updated	"2026-06-22T00:00:00.000Z"
external_version	Current Claude family — Fable 5, Opus 4.8, Sonnet 4.6, Haiku 4.5 (June 2026)
changelog	- 2.0.0: Update to the current model family and the adaptive-thinking + effort API (budget_tokens is removed on current models). Patterns are model-agnostic. - 1.0.0: Initial skill for Opus 4.5 extended thinking patterns

Extended & Adaptive Thinking

This skill covers Claude's ability to reason deeply before responding — both the prompt patterns that elicit genuine deliberation (model-agnostic, below) and the current thinking API (how to turn it on and tune its depth). It applies to the current Claude family: Fable 5 (most capable), Opus 4.8 (default), Sonnet 4.6, and Haiku 4.5.

Model IDs and API details move fast. This skill is dated; always confirm against platform.claude.com.

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How thinking works today (the API)

The modern control is adaptive thinking plus the effort parameter — not a fixed token budget. The older thinking: {type: "enabled", budget_tokens: N} is deprecated on Opus 4.6 and removed (returns a 400) on Opus 4.7, Opus 4.8, and Fable 5 — do not use it on current models.

# Current pattern (Opus 4.8 / 4.7 / 4.6, Sonnet 4.6)
response = client.messages.create(
    model="claude-opus-4-8",
    max_tokens=16000,
    thinking={"type": "adaptive", "display": "summarized"},  # default display is "omitted"
    output_config={"effort": "high"},  # low | medium | high | xhigh | max
    messages=[{"role": "user", "content": "Solve this step by step..."}],
)

• effort controls depth and overall token spend. Use xhigh for coding/agentic work and a minimum of high for most intelligence-sensitive tasks; drop to medium/low for routine work. max is for the hardest, latency-insensitive cases (max/xhigh are Opus-tier + Fable 5, not Haiku).
• display defaults to "omitted" on Fable 5 / Opus 4.8 / 4.7 (thinking still happens and is billed; the text is just empty). Set "summarized" to surface a readable summary to users.
• Fable 5: thinking is always on — omit the thinking parameter entirely (an explicit {type: "disabled"} 400s), and the raw chain of thought is never returned (only summaries).
• Stream any request with a large max_tokens (>~16K) to avoid HTTP timeouts.

Everything below is about eliciting good deliberation through prompting — it works regardless of which model or effort level you choose.

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Understanding deliberate reasoning

What it is

Adaptive/extended thinking lets the model:

• Deliberate longer before producing output
• Consider multiple perspectives and approaches
• Self-critique and refine reasoning
• Handle complex multi-step problems
• Produce more thoughtful, less reactive responses

When it engages

With adaptive thinking on, the model decides when and how much to think — typically when:

• Problems require multi-step reasoning
• Questions have nuance or ambiguity
• Tasks require weighing tradeoffs
• Complex analysis or synthesis is needed
• Creative work benefits from deliberation

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Prompt Patterns for Deep Thinking

Pattern 1: Explicit Deliberation Request

Before answering, take time to:
1. Consider the problem from multiple angles
2. Identify potential pitfalls or edge cases
3. Weigh different approaches
4. Then provide your best response

Question: [Your complex question]

Pattern 2: Multi-Perspective Analysis

I need a thorough analysis of [topic].

Please consider:
- The technical perspective
- The business/practical perspective
- The user/human perspective
- Potential risks and downsides
- Long-term implications

Take your time to reason through each before synthesizing.

Pattern 3: Step-by-Step Reasoning

Walk me through your reasoning on this problem step by step.
Don't jump to conclusions - show your work.

Problem: [Complex problem]

For each step, explain:
- What you're considering
- Why you're making that choice
- What alternatives you rejected and why

Pattern 4: Devil's Advocate

I'm planning to [action/decision].

Before you help me execute this:
1. Steelman the opposing view - what's the best argument against?
2. What am I potentially missing or underweighting?
3. What would make this fail?
4. Only then, if it still seems right, help me proceed.

Pattern 5: Synthesis Request

I have [number] different sources/perspectives on [topic]:
[List them]

Please synthesize these into a coherent understanding that:
- Identifies where they agree
- Explains where they conflict and why
- Weighs the evidence/arguments
- Provides your reasoned conclusion

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Task Types That Benefit Most

1. Strategic Planning

Prompt pattern:
"Help me think through [strategic decision].
Consider: current state, desired outcome, constraints,
multiple paths, risks of each, second-order effects.
Don't rush to a recommendation - reason through thoroughly first."

2. Code Architecture Decisions

Prompt pattern:
"I'm deciding between [Option A] and [Option B] for [system].
Before recommending, analyze:
- Scalability implications
- Maintenance burden
- Team capability fit
- Migration complexity
- What we might regret in 2 years"

3. Creative Development

Prompt pattern:
"I want to create [creative work] about [theme].
Before writing, explore:
- Different narrative approaches
- Tonal variations
- Structural options
- What makes this theme resonate
Then develop the direction that feels most promising."

4. Problem Diagnosis

Prompt pattern:
"[System/situation] is exhibiting [problem].
Don't jump to the obvious cause.
Consider:
- What are all possible causes?
- What evidence supports/refutes each?
- What's the most likely root cause?
- What would I need to verify to be sure?"

5. Research Synthesis

Prompt pattern:
"Help me understand [complex topic].
I need you to:
- Break down the key concepts
- Explain how they relate
- Identify what's well-established vs debated
- Note what's commonly misunderstood
- Synthesize into a coherent mental model"

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Anti-Patterns to Avoid

❌ Rushing to Action

Bad: "Write me a function that does X"
Better: "I need a function that does X. Before coding,
        let's consider: edge cases, error handling,
        interface design, testing approach."

❌ Accepting First Answer

Bad: "What's the best database for my app?"
Better: "What database should I use for [specific requirements]?
        Consider multiple options, tradeoffs between them,
        and what factors should weight most heavily."

❌ Binary Thinking

Bad: "Should I do A or B?"
Better: "I'm choosing between A and B, but I'm open to
        alternatives I haven't considered. What's the
        best path forward given [context]?"

❌ Ignoring Uncertainty

Bad: "Tell me the answer to [complex question]"
Better: "Help me understand [complex question].
        Be explicit about what's certain vs uncertain,
        and what evidence supports different views."

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Extended Thinking Triggers

Use these phrases to encourage deeper deliberation:

Analytical Triggers:

• "Think through this carefully..."
• "Consider all angles before responding..."
• "What are the non-obvious implications?"
• "What am I likely missing?"
• "Reason through step by step..."

Critical Triggers:

• "What could go wrong with this approach?"
• "Steelman the opposing view..."
• "What's the strongest argument against?"
• "What assumptions am I making?"
• "Where might this reasoning break down?"

Synthesis Triggers:

• "How do these pieces fit together?"
• "What's the underlying pattern?"
• "Synthesize into a coherent view..."
• "What's the essence of this?"
• "How would you explain this to an expert?"

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Output Quality Indicators

Signs extended thinking is working well:

• Response acknowledges complexity and tradeoffs
• Multiple perspectives are genuinely considered
• Reasoning is visible, not just conclusions
• Uncertainty is explicitly addressed
• Edge cases and risks are surfaced proactively
• Recommendations are nuanced, not absolute

Signs it might need more prompting:

• Quick, surface-level response
• Only one perspective considered
• Confident without showing reasoning
• Missing obvious complexities
• Generic advice without context fit

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Combining with Other Patterns

Extended Thinking + Agentic Execution

"First, think through the best approach to [task].
Consider alternatives and tradeoffs.
Once you have a clear plan, execute it autonomously,
but note any decision points where you chose between options."

Extended Thinking + Iterative Refinement

"Draft an initial approach to [problem].
Then critique your own draft - what could be better?
Revise based on your critique.
Show me both the final version and key improvements you made."

Extended Thinking + User Collaboration

"Analyze [situation] and identify the key decision points.
For each decision, explain the tradeoffs.
Before proceeding, I'll tell you my priorities,
then you can recommend the path that fits best."

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When NOT to Use Extended Thinking

Some tasks benefit from quick, direct responses:

• Simple factual questions
• Straightforward code snippets
• Clear instructions with no ambiguity
• Tasks where speed matters more than depth
• Follow-up execution after thinking is done

For these, don't add complexity. Just ask directly.

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Model notes (current family)

• Fable 5 — Anthropic's most capable model for the hardest reasoning and long-horizon agentic work; thinking is always on. Reserve for genuinely demanding tasks (it is priced above Opus tier).
• Opus 4.8 — the default for strong reasoning and agentic work; adaptive thinking + effort.
• Sonnet 4.6 — best balance of speed and intelligence; supports adaptive thinking.
• Haiku 4.5 — fastest/cheapest for simple, latency-sensitive tasks (no xhigh/max effort).

All current models excel at sustained reasoning chains, self-correction when given space, nuanced "it depends" answers, and multi-factor synthesis — raise effort before adding prose scaffolding when you need more rigor.

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Integration with FrankX System

Use extended thinking for:

• Starlight Council decisions - Strategic synthesis across domains
• Architecture planning - System design for Arcanea, FrankX projects
• Content strategy - Weighing positioning, audience, platform fit
• Creative development - Book outlines, course structures, music direction
• Technical decisions - Framework choices, MCP design, agent orchestration

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Extended thinking is about quality of cognition, not length of output. The best responses come from genuine deliberation - use these patterns to unlock that capability.