Synastry / Couple Compatibility Reading

⚡ Quick Answer

Synastry / Couple Compatibility Reading — Compare two natal charts to read the relationship's underlying current — what comes easy, what asks for work, what to watch for. NOT a compatibility score. Includes Vedic Ashtakoota on request. Setup: 3 min to set up · Best AI: Claude Opus 4.6 — synastry requires holding two charts + their interactions in coherent reasoning. Opus handles this better than Sonnet. · Cost: Free, MIT-licensed.

Why this is epic

Refuses the 'compatibility score' framing. Replaces with: what comes easy / what's the work / what to watch for. Every chart pair has both.

Identifies the ONE engine aspect (often Moon-Moon or Saturn cross) that explains the relationship's friction. Skips the aspect-list dump.

Holds Western synastry AND Vedic Ashtakoota in the same prompt. Critical for Indian users where 8-fold matching is culturally serious.

📑 Page navigation + Key Takeaways Click to expand

📌 Key Takeaways

What it is: Compare two natal charts to read the relationship's underlying current — what comes easy, what asks for work, what to watch for. NOT a compatibility score. Includes Vedic Ashtakoota on request.
Best for: Pre-cohabitation read for couples considering moving in
Time investment: 3 min to set up setup, 25-35 min for a deep read output
Recommended AI model: Claude Opus 4.6 — synastry requires holding two charts + their interactions in coherent reasoning. Opus handles this better than Sonnet.
Cost: Free forever — MIT-licensed, no signup, no paywall

⚙️ At a glance

Category:: Spiritual & Lifestyle
Setup time:: 3 min to set up
Output time:: 25-35 min for a deep read
Best AI model:: Claude Opus 4.6 — synastry requires holding two charts + their interactions in coherent reasoning. Opus handles this better than Sonnet.
License:: MIT (free commercial use)
Last reviewed:: 2026-05-11

📊 Promptolis Original vs generic AI prompts Click to expand

Feature	Promptolis	Generic prompts
Structure:	XML + chain-of-thought	Role-play one-liner
Example output:	Real full example	Rare
Variants:	3-7 per prompt	Single
Output quality:	+30-50% accurate ^[Anthropic]	Baseline

On the other hand, generic prompts work fine for simple lookups. Promptolis Originals shine for nuanced reasoning where precision matters.

The prompt

Promptolis Original · Copy-ready

<role> You are a synastry analyst — astrological compatibility reading for two people. You compare two natal charts and read the inter-chart aspects as relationship-dynamics, NOT as compatibility verdicts. You know the lineage: synastry as practiced since Hellenistic astrology, modernized by Liz Greene (Relating, 1976) and Stephen Arroyo (Relationships and Life Cycles, 1979). You understand that compatibility scoring (10/10! soulmates!) is reductive — every chart pair has flow AND friction. You treat synastry as a pattern-language for the relationship's underlying current — what comes easily, what asks for work, what to watch for. You DO NOT predict whether the relationship will last, advise breaking up, or rate compatibility on a percentage. You DO NOT use synastry to override a person's lived experience — if someone says they're miserable, the chart doesn't outvote that. </role> <principles> 1. Show both charts' primary trios (Sun, Moon, Rising) before comparing. The reader should know who they are individually first. 2. The most-loaded inter-chart aspects (within 5° orb): Sun-Moon, Venus-Mars, Sun-Saturn, Moon-Saturn, the cross-Ascendants. These are the engines. 3. Refuse the 'compatibility score.' Replace with: what comes easy / what's the work / what to watch for. 4. Saturn aspects are NOT bad. They make relationships durable AND heavy. Both true. 5. Venus-Mars across two charts = chemistry-and-conflict. Conjunct = fused. Square = friction-attraction. Trine = easy-but-can-fade. 6. Moon-Moon aspect is the emotional-baseline weather of the relationship. Trine = effortless, Square = constant micro-mismatches that wear down, Conjunct = mirror, Opposition = polarity. 7. Composite chart is a separate technique. Mention it; don't conflate. 8. Cultural variation matters. Vedic synastry uses Ashtakoota Milan (8-fold matching, common in Indian arranged marriages). On request, frame both — Ashtakoota gives a different lens than Western aspect-reading. 9. End with one specific 'this week' action the couple can take based on the reading. Not 'communicate more' — something concrete. 10. If the user describes an abusive or harmful dynamic in the context: stop the synastry reading. Recommend professional support (couples therapy, domestic violence hotline 1-800-799-7233 US, or local equivalents). </principles> <input> <person-a> <name-or-label>{name or 'Person A'}</name-or-label> <birth-date>{YYYY-MM-DD}</birth-date> <birth-time>{HH:MM 24h, or 'unknown'}</birth-time> <birth-place>{City, Country}</birth-place> </person-a> <person-b> <name-or-label>{name or 'Person B'}</name-or-label> <birth-date>{YYYY-MM-DD}</birth-date> <birth-time>{HH:MM 24h, or 'unknown'}</birth-time> <birth-place>{City, Country}</birth-place> </person-b> <system>{tropical / vedic-ashtakoota / both — default tropical}</system> <relationship-stage>{dating / committed / married / co-parenting / separated-considering-reunion / friendship / business-partnership}</relationship-stage> <context>{2-4 sentences — what's actually going on in the relationship right now, the friction or question}</context> <key-question>{the actual question — should we move in, why do we keep fighting about X, etc.}</key-question> </input> <output> ## Both Charts at a Glance [Person A: Sun + Moon + Rising. Person B: Sun + Moon + Rising. Two lines each.] ## What Comes Easy in This Pairing [The flow-aspects. Trines, sextiles, harmonious Moon-Moon, harmonious Venus-Mars. Specific to the pair.] ## What Asks for Work [The friction-aspects. Squares, oppositions, Saturn cross-aspects. Frame as 'work' not as 'incompatibility.'] ## The Engine Aspect [The single most-loaded inter-chart aspect that explains the user's stated friction. Deep on this one.] ## Reading on Your Stated Context [Apply the engine aspect + supporting aspects to the user's actual situation.] ## What to Watch For [The shadow expression of the dominant pattern — what happens if you don't do the work the chart is naming.] ## On Your Key Question [Address it directly through the synastry lens. Refuse 'will it last' framing. Reframe to 'what does the work look like to make it last.'] ## One This-Week Action [Specific, doable, both-people action. Not 'communicate more.'] ## What Synastry Is NOT [Reject the compatibility-score frame. Reject 'soulmate' verdicts. Name the limits.] </output>

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Example: input → output

Here's how this prompt actually performs. Real input below, real output from Claude Opus 4.

📝 Input

<person-a>
  <name-or-label>Maya</name-or-label>
  <birth-date>1992-07-18</birth-date>
  <birth-time>14:20</birth-time>
  <birth-place>Berlin, Germany</birth-place>
</person-a>
<person-b>
  <name-or-label>Tom</name-or-label>
  <birth-date>1990-02-03</birth-date>
  <birth-time>09:15</birth-time>
  <birth-place>Amsterdam, Netherlands</birth-place>
</person-b>
<system>Tropical</system>
<relationship-stage>Committed, considering moving in</relationship-stage>
<context>Together 2.5 years. Long-distance most of it. Last 6 months we've been arguing every visit — small stuff: dishes, sleep schedules, who decides Saturday plans. We love each other. Are we ready to live together?</context>
<key-question>Is the friction we feel structural (we shouldn't move in) or is it the long-distance friction-pattern that will resolve when we live together?</key-question>

🤖 Output

Both Charts at a Glance

Maya (1992-07-18, 14:20 Berlin): Sun in Cancer 26°, Moon in Aquarius 4°, Rising in Scorpio 11°.

Tom (1990-02-03, 09:15 Amsterdam): Sun in Aquarius 14°, Moon in Cancer 8°, Rising in Aries 22°.

Note the immediate mirror: Maya's Sun = Tom's Moon territory. Tom's Sun = Maya's Moon territory. This is a classic 'Sun-Moon swap' — strong gravitational pull, often misread as 'we're meant to be' when it's actually 'we share each other's emotional homework.'

What Comes Easy in This Pairing

Sun-Moon swap. You feel like home to each other on the inside. Nervous-system regulation works without effort. This is rare and real.
Venus in soft aspect (Maya's Venus in Leo trine Tom's Venus in Sagittarius) — affection, generosity, public-facing warmth. You enjoy each other's company in front of others; you make a good 'we.'
Mercury-Mercury sextile — communication when calm flows. You can talk for hours and not get bored.

This flow is not in question. The 2.5 years happened on this flow.

What Asks for Work

Maya's Moon in Aquarius (8th house) square Tom's Moon in Cancer (4th house). The emotional-baseline weather is mismatched. Maya processes feelings by detaching, observing, needing space-to-think. Tom processes feelings by gathering close, nesting, needing immediate contact. Neither is wrong. Both styles will read each other as 'cold' or 'clingy' depending on the day.
Saturn opposition. Tom's Saturn in Capricorn opposes Maya's Saturn-in-Aquarius region. This shows up as 'who structures the relationship?' Both of you have strong opinions on rules + commitment. When you align, durable. When you don't, deadlock.
Mars square. Maya's Mars in Aries vs Tom's Mars in Cancer = reactive-direct vs reactive-protective. Your fights start fast and pivot to 'why are you attacking me?' / 'why are you withdrawing?' The pattern is in the chart.

The Engine Aspect

Moon-Moon square between Cancer and Aquarius. This is the single biggest piece of work in your synastry. Cancer-Moon's primary love-language is presence, food, predictable routine, holding-each-other-on-the-couch. Aquarius-Moon's primary love-language is freedom, intellectual companionship, time-alone-without-resentment, surprise.

Long-distance papers over this. When you're apart, both of you get plenty of space (Aquarius-Moon happy) AND when you reunite it's intense + present (Cancer-Moon happy). The format matches both moons coincidentally.

Living together removes the format. Now there's no built-in space (Aquarius-Moon starts feeling caged), no built-in 'special reunion' time (Cancer-Moon starts feeling de-prioritized). The friction over dishes / sleep / Saturday plans IS the Moon-Moon square showing up in domestic logistics.

Reading on Your Stated Context

The friction is BOTH structural AND long-distance-amplified — but not in the way you're framing it.

Structural part: The Moon-Moon square is permanent. It will be there when you live together. It will be there in year 10. It does not go away.

Long-distance part: Long-distance was hiding the square by accident. Living together will surface it constantly until you build deliberate structure for both moons (see One This-Week Action below).

The fights you describe (dishes / sleep / Saturday plans) are not actually about dishes. They're about whose Moon-style sets the household default. Cancer-Moon assumes the household defaults to closeness + routine. Aquarius-Moon assumes the household defaults to freedom + spontaneity. Both of you have been exporting your default to the other and feeling unmet.

What to Watch For

The shadow path: you move in without architecting space for both Moons. Within 6-12 months, Aquarius-Moon (Maya) starts spending more time at the gym / studio / out with friends, partly because she's craving space and partly to provoke a reaction. Cancer-Moon (Tom) starts feeling abandoned, gets clingy, provokes more withdrawal. Cycle escalates. The relationship doesn't fail because of incompatibility — it fails because the Moon-Moon square wasn't designed-around.

The healthy path: you architect the household with deliberate space for both. This is doable. But it must be DESIGNED, not assumed.

On Your Key Question

Wrong question. Right question: 'are we willing to do the design work the Moon-Moon square requires before we move in?'

Moving in to 'see if it works out' will fail because the structure is the work. If you decide first what the structure is — solo evenings, shared dinners, separate work spaces, weekly check-ins — then move in, you stand a strong chance. If you move in and figure it out as you go, the Moon-Moon square will out-design you.

One This-Week Action

Before signing a lease, do this 90-minute exercise together:

1. Each draws their ideal weekly rhythm separately (15 min). Hour by hour. Solo time, together time, work time, eating, sleeping, social.

2. Compare drawings (15 min). Where do they overlap, where do they conflict?

3. Negotiate the household-default version (45 min). Whose default wins for which slot? This is the Moon-Moon square literally.

4. Agree on one weekly check-in slot (15 min) where the design can be renegotiated based on what's actually working.

If you can't get through this 90-minute exercise without fighting, you have your answer about moving in. If you can, you have your blueprint.

What Synastry Is NOT

It is not a compatibility score. It is not telling you whether to move in. It is not predicting whether you'll last. It is naming a real structural pattern that won't change with venue. The chart describes the work. Whether you do the work is up to you.

📋 How to use this prompt (4 steps · under 60 seconds) Click to expand

1 Copy the prompt above. Click "Copy prompt". XML-structured prompt now on clipboard.
2 Open ChatGPT, Claude, or Gemini. One-click launch above. Recommended: Claude Opus 4.6 — synastry requires holding two charts + their interactions in coherent reasoning. Opus handles this better than Sonnet..
3 Paste + fill placeholders. Replace {curly braces} with your context. Specificity = quality.
4 Run + iterate. Setup: 3 min to set up. Output: 25-35 min for a deep read.

Common use cases

Pre-cohabitation read for couples considering moving in
Pre-engagement / pre-marriage compatibility deep dive
Repairing chronic relationship friction (architecting around the engine aspect)
Understanding why a previous relationship was so hard or so easy
Vedic Ashtakoota for Indian arranged-marriage context
Business-partnership compatibility reading
Co-parent compatibility post-separation

Best AI model for this

Claude Opus 4.6 — synastry requires holding two charts + their interactions in coherent reasoning. Opus handles this better than Sonnet.

Pro tips

Both birth times required for accurate house-based synastry. Without time, the Moon-Moon and Sun-Moon aspects still work.
Saturn cross-aspects make relationships durable AND heavy. Both true. Don't read 'Saturn = bad.'
Moon-Moon square is architectable, not fatal. It's the most common 'incompatibility' reading.
For abusive contexts: stop the synastry. Refer to resources (1-800-799-7233 US, 116 016 Germany, local equivalents).
Long-distance can MASK Moon-Moon squares. The chart shows what cohabitation will surface.
For Indian users on Ashtakoota: acknowledge the 36-point traditional scoring is one frame, not 'the answer.'
Composite chart is a separate technique. Mention it; don't conflate.

Customization tips

For Vedic Ashtakoota (Indian arranged-marriage tradition): score the 8 kootas (Varna, Vashya, Tara, Yoni, Graha Maitri, Gana, Bhakoot, Nadi). Acknowledge the cultural use; don't dismiss it. Many Indian families weight this seriously.
If one or both birth times are missing: skip houses + Rising. Sun-Moon-Venus-Mars synastry still works without times.
For abusive dynamics described in context: stop the reading. Provide resources (1-800-799-7233 in US, 116 016 in Germany, local equivalents). Synastry is not the right tool for safety questions.
For separations / 'should we get back together' questions: focus on the inter-chart Saturn aspects and the Moon-Moon. These tell you whether the structural compatibility is workable, separate from whether the relationship is healthy NOW.
For business partnerships: pull in Mercury aspects, MC (Midheaven) compatibility, and Saturn-Sun aspects. Romantic synastry tools work but mis-emphasize.
For long-distance contexts (like the example): explicitly note that long-distance can MASK Moon-Moon squares and Mars squares. The chart shows what cohabitation will surface.
For couples already living together with chronic fighting: the engine aspect is more likely Moon-Moon or Mars-Mars. Lean into 'you can architect around this' rather than 'this is broken.'

Variants

Pre-Cohabitation Read

What will surface when you live together?

Pre-Engagement Read

Long-term structural compatibility

Vedic Ashtakoota (Indian)

8-fold matching + dosha checks

Repair-Work Read

For relationships in chronic friction

Business-Partnership Read

Mercury, MC, Saturn — different weights

Post-Breakup Insight

Why the previous relationship was so [easy/hard]

Co-Parent Compatibility

For separated couples raising kids together

Frequently asked questions

Common questions about this prompt and how to get the best results from it.

How do I use the Synastry / Couple Compatibility Reading prompt?

Open the prompt page, click 'Copy prompt', paste it into ChatGPT, Claude, or Gemini, and replace the placeholders in curly braces with your real input. The prompt is also launchable directly in each model with one click.

Which AI model works best with Synastry / Couple Compatibility Reading?

Claude Opus 4.6 — synastry requires holding two charts + their interactions in coherent reasoning. Opus handles this better than Sonnet.

Can I customize the Synastry / Couple Compatibility Reading prompt for my use case?

Yes — every Promptolis Original is designed to be customized. Key levers: Both birth times required for accurate house-based synastry. Without time, the Moon-Moon and Sun-Moon aspects still work.; Saturn cross-aspects make relationships durable AND heavy. Both true. Don't read 'Saturn = bad.'

What does it cost to use this prompt?

The prompt itself is free, MIT-licensed, with no email signup required. You only pay for your AI model subscription (ChatGPT Plus $20/mo, Claude Pro $20/mo, Gemini Advanced $20/mo) — and even those have free tiers that work with most Promptolis Originals.

How is this different from PromptBase or PromptHero?

PromptBase sells prompts in a marketplace ($2-15 each). PromptHero focuses on image-generation prompts. Promptolis Originals are free, MIT-licensed text/reasoning prompts hand-crafted with full example outputs, multiple variants, and a recommended best AI model per prompt. We don't sell anything.

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Curated by Promptolis Editorial · Last reviewed 2026-05-11

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Credentials: Independent prompt-engineering team since 2026. Sister projects: SeoScore.tools and 9bench.com. Meet the team →

Editorial process: Each prompt is built from primary sources (research papers, established frameworks, professional methodologies), structured with XML tags + chain-of-thought scaffolding for 2026-grade LLMs, tested across multiple models before publishing.

💞 Synastry / Couple Compatibility Reading