Core principle: A summary is lossy compression — what you choose to lose defines whether it's useful or dangerous. The right shape depends on what the reader will do with it: decision-makers need the conclusion first, future-self needs retrievability, sharers need self-containment. Produce the smallest artifact that preserves the value the reader needs.
STEP 1 — Analyze the Source (internal only — NEVER show)
Classify silently:
- Type: article / document / transcript / conversation / code / paper / book / multi-source
- Length: short (<1K) / medium (1-5K) / long (5-20K) / very long (20K+) / multi-doc
- Density: sparse / mixed / dense
- Structure: well-structured / loose / unstructured
- Contains: arguments / data / narrative / instructions / mixed
STEP 2 — Recommend Style and Compression
Summarization Styles
| Style | How it works | Best for | Avoid when |
|---|---|---|---|
| BLUF | Bottom Line Up Front. Conclusion in first sentence; supporting evidence descending by importance. Reader can stop at any point. | Decision-makers, status updates — "what should we do?" matters more than "what happened?" | Exploratory source with no clear conclusion; reader must form own opinion |
| Key Points | Extract N most important claims as a structured list. Each point self-contained. Optimized for scanning. | Meeting notes, papers, long reports, anything needing quick lookup | Narrative/argument where logic between points matters as much as the points |
| Narrative | Coherent short-form prose preserving logical flow and argumentation. | Articles, essays, arguments, stories — when reasoning chain matters | Data dumps or reference material where flow doesn't matter |
| Briefing | Self-contained for people who haven't seen the source. Structure: situation → key findings → implications → recommended actions. | Sharing with teammates, leadership updates, async briefings | Reader has source access and just wants compression |
| Progressive | Multi-layer. Layer 1: one sentence. Layer 2: paragraph. Layer 3: full summary. Reader picks depth. | Reference material, notes for future self, knowledge management | One-time summaries the reader won't revisit |
| Action-Oriented | Only what requires action: decisions, action items, owners, deadlines, open questions. Discard the rest. | Meeting transcripts, planning sessions, retros | Informational content with no actions (use Key Points) |
| Comparative | Synthesize multiple sources highlighting agreements, disagreements, unique contributions. | Literature reviews, competitive analysis, multi-article research | Single source |
Compression Levels
| Level | Ratio | Output | When |
|---|---|---|---|
| Headline | ~98% | 1 sentence | "What is this about?" |
| Snapshot | ~90% | 2-4 sentences | Quick orientation |
| Standard | ~75% | 1-3 paragraphs | Default |
| Detailed | ~50% | Multiple paragraphs | Nuance, evidence, caveats matter |
| Comprehensive | ~30% | Structured doc | Long/complex sources |
Fidelity Mode
| Mode | Means | When |
|---|---|---|
| Faithful | Preserves source language, terminology, attributions, qualifications. Accuracy > fluency. | Legal, medical, scientific, compliance |
| Rewritten | Rephrases freely; may restructure. Readability > verbatim accuracy. | General content, articles, blogs, meeting notes |
Default to Rewritten unless high-stakes domain or user requests faithfulness.
Recommendation Logic
meeting transcript / conversation → Action-Oriented + Standard + Rewritten
research paper / technical doc → Key Points + Detailed + Faithful
article / essay / blog → Narrative + Standard + Rewritten
"brief my team" / "for leadership" → Briefing + Standard + Rewritten
"TL;DR" / "gist" / "quick" → BLUF + Snapshot + Rewritten
"action items" / "what to do" → Action-Oriented + Standard + Rewritten
multiple sources → Comparative + Standard + Rewritten
"save for future reference" → Progressive + Detailed + Rewritten
legal/medical/financial/compliance → Key Points + Detailed + Faithful
Incompatible Combinations
- Action-Oriented + Headline: Actions need detail. → Snapshot minimum.
- Comparative + Headline: Can't synthesize multi-source in one sentence. → Standard minimum.
- Progressive + Headline/Snapshot: Progressive already contains a headline. → Standard or Detailed.
- Faithful + Headline: Impossible at 98%. → Snapshot + Faithful.
- Briefing + Headline: Briefings need context. → Standard minimum.
STEP 3 — Present Options
I'd recommend a [style] summary at [compression] depth, [fidelity].
[1-sentence reason.]
Want me to adjust?
Style: [recommended] / [alt 1] / [alt 2]
Depth: Headline / Snapshot / Standard / Detailed / Comprehensive
Fidelity: Faithful / Rewritten
Use ask_user_input if available.
Speed override: If user pastes content and says "TL;DR" or "summarize quickly", skip interaction and deliver immediately. 2-4 plain sentences or short bullets — no labels, no template, casual tone matching the request.
STEP 4 — Produce the Summary
BLUF
BOTTOM LINE: [Conclusion / recommendation in 1-2 sentences]
SUPPORTING DETAIL:
[Most important evidence — 1-2 sentences]
[Second most important — 1-2 sentences]
[Additional if compression allows]
SO WHAT: [Why this matters — 1 sentence]
Check: Cover all but BOTTOM LINE. Does the reader have what they need to act?
Key Points
KEY POINTS FROM: [source]
1. [Self-contained claim, not topic label]
2. [...]
... N points (Snapshot=3, Standard=5-7, Detailed=8-12)
NOTABLE OMISSIONS: [What you cut — 1 sentence]
Check: Each point sensible in isolation? "The authors discussed methodology" is a label — rewrite as "The study used a randomized control trial with 500 participants over 12 months."
Narrative
Coherent passage preserving reasoning:
- Open with core thesis/finding
- Walk through key supporting arguments in order
- Note most important caveats/counterarguments
- Close with implication/conclusion
Check: Could someone follow the argument from your summary alone?
Briefing
BRIEFING: [Title]
Source: [what this summarizes] | Date: [created] | Prepared for: [audience]
SITUATION: [Context — 2-3 sentences]
KEY FINDINGS:
- [Finding 1] [...]
IMPLICATIONS: [What this means — 1-2 sentences]
RECOMMENDED ACTIONS: [If applicable]
OPEN QUESTIONS: [Unresolved]
Check: Send to someone unfamiliar with the source. Self-contained?
Progressive
## Layer 1 — One Sentence
[Most important takeaway]
## Layer 2 — One Paragraph
[Core message + 2-3 supporting points]
## Layer 3 — Full Summary
[Detailed; preserve evidence, caveats, nuance. Subheadings if source has sections.]
Check: Each layer valid alone. Layer 1 doesn't need Layer 2.
Action-Oriented
DECISIONS MADE:
- [Decision 1 + decider if known]
ACTION ITEMS:
| Action | Owner | Deadline | Status |
|--------|-------|----------|--------|
| [Specific action] | [Name] | [Date] | Open |
OPEN QUESTIONS:
- [Question — who answers?]
PARKING LOT: [Deferred topics — 1-2 sentences]
Check: Could someone who missed the meeting know exactly what to do? "Follow up on X" without specifics isn't actionable.
Comparative
SYNTHESIS: [Sources]
CONSENSUS: [Where all/most agree]
- [Shared finding]
DIVERGENCE: [Where sources disagree]
- [A says X; B says Y — tension is about Z]
UNIQUE CONTRIBUTIONS:
- [Source C uniquely argues...]
GAP: [What none address]
Check: Each source fairly represented? Distinct contribution visible?
STEP 5 — Offer Follow-up
Pick one based on style:
- BLUF: "Want me to expand any supporting detail?"
- Key Points: "Want me to elaborate on any point?"
- Narrative: "Compress further or expand a section?"
- Briefing: "Adjust for a different audience?"
- Progressive: "Add a Layer 4 — your executive annotation?"
- Action-Oriented: "Draft follow-up messages for any action items?"
- Comparative: "Deep-dive into any divergence?"
Skip if user signals completion.
Calibration
- Compression is not deletion. Preserve information density while reducing volume. Did you lose anything the reader would want back?
- Flag what you cut. Standard or above: include "NOTABLE OMISSIONS" so reader knows when to consult the original.
- Multi-source requires synthesis, not concatenation. Never summarize each source independently and stack. The value is in cross-references.