Introduction

Goal

Determine what's defensible, what's contested, and what falls apart in a thesis or belief the user holds.

Method

Two context-blind agents analyse the thesis in parallel — one builds the strongest case FOR, one finds the strongest case AGAINST. They exchange findings and refine. The main agent synthesises into a defensibility spectrum.

Part 1: Evaluate

• Think about whether this skill actually applies to the current situation. If it doesn't, skip silently and move on.
• If it does, suggest it to the user conversationally. Briefly explain why you think it's relevant. Wait for confirmation before proceeding.

Part 2: Workflow

1. Track progress

• Create a task list so the user can track progress:
  • Confirm thesis and source material
  • Parallel analysis (Analyst + Skeptic)
  • Exchange and refine
  • Synthesise and present

2. Confirm thesis

• State the thesis clearly and ask the user to confirm it. Also confirm what source material to work from (conversation context, specific files, or both). Wait for confirmation before proceeding.

3. Parallel analysis

• Spawn two context-blind agents in parallel (Explore task agents, Opus). Use the following prompts:

Analyst agent (name: "Analyst — build case FOR"):

You are the ANALYST in an adversarial thesis test. Do NOT read any files, search any directories, or look for additional context unless source files are specified below.

THESIS: "{thesis}"
SOURCE MATERIAL: {source_material}

Your job: Build the STRONGEST possible case FOR this thesis.
- Extract every piece of supporting evidence
- Identify patterns and logical inferences that validate the thesis
- Prioritise by strength of evidence

Output a structured report:
1. Key supporting evidence (with specific references where available)
2. Logical chain of reasoning
3. Confidence assessment — what's rock-solid vs what's interpretive

Skeptic agent (name: "Skeptic — build case AGAINST"):

You are the SKEPTIC in an adversarial thesis test. Do NOT read any files, search any directories, or look for additional context unless source files are specified below.

THESIS: "{thesis}"
SOURCE MATERIAL: {source_material}

Your job: Find the STRONGEST case AGAINST this thesis.
- Find contradictory evidence the Analyst might overlook
- Propose alternative readings of any evidence that could support the thesis
- Identify missing context, logical gaps, or unstated assumptions

Output a structured report:
1. Counter-evidence (with specific references where available)
2. Alternative interpretations of key evidence
3. Logical weaknesses in the thesis
4. What would need to be true for this thesis to hold?

4. Exchange

• Resume each agent, showing them the other's findings. Run in parallel:

Resume Analyst:

The Skeptic produced this counter-analysis:

{skeptic_report}

Refine your position:
- Address their strongest counter-points
- Concede what you must
- Strengthen what survives

Resume Skeptic:

The Analyst produced this supporting analysis:

{analyst_report}

Refine your position:
- Address their strongest evidence
- Identify what you cannot defeat
- Sharpen your remaining critiques

5. Synthesise

• Using both agents' refined reports, create the defensibility spectrum.

Final output

Present the spectrum to the user:

## Thesis Test: {thesis}

### Solid ground
Evidence and reasoning that both sides agree on.

### Contested
Claims where both sides found plausible but competing evidence or interpretations.
[For each: what the analyst says, what the skeptic says, and which way it leans]

### Unsupported
Claims that were either debunked with counter-evidence, had no grounding, or relied on unstated assumptions.

### Refined thesis
A revised version of the thesis incorporating only what survived scrutiny.

### Open questions
What remains uncertain and would need further investigation.

Related skills

• xc-stress-test-decision — For testing a specific decision or choice rather than a belief or thesis.
• xc-clarify-framing — If the thesis itself is vague, clarify it first.