- name
- book-mirror
- version
- 0.5.0
- description
- Take any book (EPUB/PDF), produce a personalized chapter-by-chapter analysis. Each chapter is preserved in detail (The Chapter) and mirrored back to the reader's actual life (The Mirror) using brain context. The mirror observes and resonates — a friend pointing out parallels, NOT a consultant rearranging the reader's life, NOT a therapist assigning homework. The reader decides what to do about it. Layout is a top-aligned HTML table or stacked sections, never a bare markdown pipe table (pipe tables center-misalign uneven columns). Output is a single brain page at media/books/<slug>-personalized.md plus an optional PDF via brain-pdf.
- triggers
- ["personalized version of this book","mirror this book","two-column book analysis","apply this book to my life","how does this book apply to me"]
- mutating
- true
- writes_pages
- true
- writes_to
- ["media/books/"]
- upstream
- book-mirror@fc834ee
# book-mirror — Personalized Chapter-by-Chapter Book Analysis
> **Convention:** see [_brain-filing-rules.md](../_brain-filing-rules.md) for the
> sanctioned `media/<format>/<slug>` exception this skill files under.
>
> **Convention:** see [conventions/quality.md](../conventions/quality.md) for
> citation rules, back-link enforcement, and output quality bars.
>
> **Convention:** see [conventions/brain-first.md](../conventions/brain-first.md)
> for the lookup chain (brain → search → external) the context-gathering
> phase follows.
## What this does
Given a book (EPUB or PDF), produce a brain page where every chapter is
summarized in detail on one side ("The Chapter") and mirrored back to the
reader's actual life on the other ("The Mirror"), using their own words,
situations, people, and patterns from the brain. Output is a brain page at
`media/books/<slug>-personalized.md`.
This is NOT a generic book summary. The mirror is the value: it makes the
book read like a smart friend who happens to know the reader's life deeply
is pointing things out in the margins. The mirror's job is recognition —
"that's exactly me" — and then getting out of the way. If the user wants a
flat summary instead, route them to a different skill.
## Trust contract (read this before running)
book-mirror runs as a CLI command (`gbrain book-mirror`), NOT as a pure
markdown skill that the agent dispatches via tools. The CLI is the trusted
runtime; the skill is the orchestration prose around it.
What this means for the agent:
- The CLI submits N read-only subagent jobs (one per chapter). Each subagent
has `allowed_tools: ['get_page', 'search']` only. They CANNOT call
put_page or any mutating op. They produce markdown analysis via their
final message.
- The CLI reads each child's `job.result`, assembles the final
page, and writes it via a single operator-trust `put_page`.
- This means untrusted EPUB/PDF content cannot prompt-inject any
`people/*` page. The trust narrowing happens at the tool allowlist,
not at the slug-prefix layer.
## The pipeline
```
1. ACQUIRE → User has the EPUB/PDF locally (manual; book-acquisition is
not currently shipped — see "Acquiring the book" below).
2. EXTRACT → Pull chapter text from EPUB/PDF into one .txt per chapter.
3. CONTEXT → Gather everything the brain knows about the reader.
4. ANALYZE → `gbrain book-mirror` fans out N read-only subagents.
5. ASSEMBLE → CLI reads each child result and writes one put_page.
6. PDF → Optional: render via skills/brain-pdf for delivery.
```
## 1. Acquiring the book
book-acquisition (legal-grey-area downloader) was deliberately not shipped
in this skill wave. The user drops the EPUB/PDF manually. Common paths the
user might use:
```bash
# User-supplied path
ls path/to/book.epub
ls path/to/book.pdf
# Or already in the brain repo (recommended for tracking)
ls $BRAIN_DIR/media/books/
```
Resolve `$BRAIN_DIR` from the gbrain config (`gbrain config get sync.repo_path`)
or accept it from the user.
## 2. Text extraction
Goal: one `.txt` file per chapter under a temp directory. The agent has
shell + python access; the CLI is downstream of this and takes the
extracted directory as input.
### EPUB
```bash
SLUG="this-book" # kebab-case
WORK="$(mktemp -d)/$SLUG"
mkdir -p "$WORK/chapters"
unzip -o path/to/book.epub -d "$WORK/unpacked"
# Find content files (XHTML/HTML), sorted (chapter order = sort order)
find "$WORK/unpacked" -name "*.xhtml" -o -name "*.html" | sort > "$WORK/files.txt"
# Strip HTML to text per chapter
python3 - <<'PY'
from bs4 import BeautifulSoup
import os, sys
work = os.environ['WORK']
files = open(f'{work}/files.txt').read().splitlines()
for i, path in enumerate(files, 1):
html = open(path, encoding='utf-8', errors='replace').read()
text = BeautifulSoup(html, 'html.parser').get_text('\n')
text = '\n'.join(line.strip() for line in text.splitlines() if line.strip())
with open(f'{work}/chapters/{i:02d}.txt', 'w') as f:
f.write(text)
PY
```
If `bs4` is missing: `pip3 install beautifulsoup4 lxml`.
Inspect the chapter files to identify which are real chapters vs front
matter (TOC, copyright, acknowledgments). Often the EPUB ships one file
per chapter; sometimes multiple chapters per file. Use
`head -5 "$WORK/chapters/"*.txt` to spot-check.
### PDF
```bash
pdftotext -layout path/to/book.pdf "$WORK/full.txt"
```
Then split by chapter heading (look for "Chapter N", "CHAPTER N", or
all-caps title lines) using `awk` or `python`. If the PDF is a scan with
no embedded text, fall back to OCR via `skills/brain-pdf` or another
vision tool.
### Quality check
For each chapter file:
- Word count > 1500 (typical chapter range 2k–8k words).
- No HTML tags.
- Paragraphs preserved with `\n\n`.
Save a `chapters/INDEX.md` mapping chapter number → title → file → word
count for reference.
## 3. Context gathering
This is the most critical step. The mirror is only as good as the
context fed to each chapter subagent.
### What to pull
1. **Templates: USER.md and SOUL.md** if the user maintains them
(gbrain ships templates at `templates/USER.md` and `templates/SOUL.md`;
they live in the brain repo when populated). Read full.
2. **Recent daily memory** — last 14 days of brain pages under
`wiki/personal/reflections/` or wherever the user files daily notes.
3. **Topic-relevant brain searches** tuned to the book's themes:
- `gbrain query "marriage"`, `gbrain query "couples therapy"` for a
marriage book.
- `gbrain query "founders"`, `gbrain query "fundraising"` for a
business book.
- `gbrain query "shame"`, `gbrain query "anger"` for a psychology book.
4. **Brain pages for relevant entities** — `gbrain query "<name>"` for
people who will likely come up.
5. **Standing patterns** — anything in the user's reflections or
originals that's been recurring.
### Deep retrieval (DEFAULT — not optional)
A thin static context pack is the #1 cause of a generic mirror. The
quality ceiling is the brain itself, not whatever got manually stuffed
into one file. Do per-section retrieval before invoking the CLI:
1. Split the book into sections (chapters, parts, or thematic units).
2. For EACH section, generate 15–20 targeted brain searches based on
what the author is saying in that section.
3. Fetch the top brain pages from those searches.
4. Fold the retrieved material into the context pack, grouped by chapter,
so each chapter subagent sees the pages that map to ITS section.
**Query generation strategy (per section):**
- Literal theme match — what is the author literally talking about?
- Psychological parallel — what pattern does this map to in the reader's life?
- Specific incident hunt — what dated events would the author be describing?
- Relationship/people parallel — who in the reader's life maps to this?
- Temporal parallel — what period of the reader's life is closest?
**Execution:**
```bash
gbrain query "QUERY" --limit 3
gbrain get "PAGE_SLUG"
```
**Budget:** 15–20 searches per section × N sections, plus 40–60 full page
fetches. All local DB queries — essentially free. Target 50–80K chars of
retrieved brain context total. The chapter subagents also carry read-only
`search` + `get_page` tools at run time, so the context pack is the floor,
not the ceiling — but do not rely on subagents to rediscover what the
orchestrating pass already found.
**Minimum retrieved material for a high-stakes mirror:**
- 40+ brain pages retrieved across all sections.
- 10+ direct quotes from the reader (verbatim from brain pages).
- Dated incidents and recurring patterns where available.
- Coverage across life domains: journal entries and reflections, work and
creative output, relationships, public/civic life, specific joyful
moments, cultural identity — not just the heaviest material.
### Assemble a context pack
Write everything to a single file the CLI can read:
```bash
CONTEXT="$WORK/context.md"
{
echo "## USER.md (if any)"
[ -f "$BRAIN_DIR/USER.md" ] && cat "$BRAIN_DIR/USER.md"
echo
echo "## SOUL.md (if any)"
[ -f "$BRAIN_DIR/SOUL.md" ] && cat "$BRAIN_DIR/SOUL.md"
echo
echo "## Recent reflections (last 14 days)"
# Pull recent daily reflections — adapt to the user's filing scheme
# ...
echo
echo "## Topic-relevant brain pages (grouped per chapter)"
# Deep-retrieval results from above, grouped by the chapter they serve
# ...
echo
echo "## Themes & cruxes"
# A 1-page summary, written by the agent, calling out:
# - What's currently active in the user's life that this book intersects
# - Specific quotes from the user that map to book themes
# - People and dates that should appear in the mirror
# - The anti-repetition constraints (domain map + phrase caps, below)
} > "$CONTEXT"
```
Make this dense. It's read by every chapter subagent. Encode the
anti-repetition constraints (next section) here — the per-chapter domain
assignment and phrase caps only work if every subagent can see them.
## Quality system (hard rules)
These rules were earned through iteration with cross-modal eval. They are
mandatory for every book-mirror.
### Principle: the Chapter half IS the variety engine
The single most important lesson: rich chapter summaries drive varied
mirrors. When you compress the source material, the mirror has nothing
to respond to except its own greatest hits. The two halves are symbiotic,
not competing for space.
**Rule:** Every distinct idea, story, framework, numbered list item, and
memorable phrase the author presents gets its own section. If the author
lists six kinds of loneliness, that's six sections. If they tell three
stories, that's three sections. The Chapter half should be detailed enough
that someone could skip the book and not lose much. The Mirror half
responds to EACH specific idea with a DIFFERENT personal mapping.
### Layout: top-aligned HTML tables OR stacked sections (hard rule)
Do **NOT** emit a bare `| The Chapter | The Mirror |` *markdown* pipe
table. GitHub (and most renderers) pad a table row's cells to equal height
and vertically *center* the shorter cell's text — so when the two halves
differ in length (they always do), one column floats down with a block of
whitespace above it. Plain markdown has no per-cell vertical-align. That
is the root cause, not a styling nit.
**Two valid containers — both are correct, pick by destination:**
1. **Top-aligned HTML table (the CLI default).** The `gbrain book-mirror`
chapter prompt already mandates an HTML `<table>` with `valign="top"`
on EVERY `<td>` — this is baked into the trusted runtime. Facts worth
knowing when hand-writing or repairing a mirror: GitHub KEEPS
`valign="top"` but STRIPS inline `style="vertical-align"`, and does NOT
render markdown emphasis inside a raw `<td>` — pre-convert emphasis to
`<em>`/`<strong>`, and use `<br><br>` for paragraph breaks within a
cell.
2. **Stacked sections** — best for mobile and chat delivery, and the
right choice for any hand-assembled mirror (children's variant,
retro-fixes of legacy pages):
```markdown
### Chapter N: <title>
**The Chapter**
<chapter prose, normal paragraphs separated by blank lines>
**The Mirror**
<mirror prose, normal paragraphs separated by blank lines>
```
Use real blank-line paragraph breaks, never `<br><br>` outside a table
cell. Reads top-to-top every time, zero alignment bug. The
Chapter/Mirror naming and the one-section-per-idea richness rule are
unchanged — only the container changes.
### Anti-repetition (hard constraints, not vibes)
"Be more varied" doesn't work as an instruction. LLMs remix the deck
they're given — if the deck is 6 cards, you get 6 cards N times. Use hard
constraints, written into the context pack's "Themes & cruxes" section:
1. **Domain mapping:** Before writing, assign each chapter a PRIMARY life
domain (career, family, civic work, creative life, a specific
relationship, childhood, intellectual life, spiritual practice, etc.).
No two adjacent chapters should share the same primary domain.
2. **Phrase caps:** No word or phrase may appear as a thematic anchor in
more than 3 chapters. Identify the reader's "greatest hits" (the 5–6
themes that would dominate without constraints) and set explicit
limits or bans.
3. **Story deduplication:** Before writing each mirror, check: "Have I
already used this story/incident/quote in a previous chapter?" If yes,
find a different one.
4. **Emotional range requirement:** At least 25% of chapters must map to
JOY, HUMOR, CREATIVE EXCITEMENT, or VICTORY — not only wounds and
struggle. When the author describes something beautiful, the mirror
should find something beautiful in the reader's life.
### The editorial rule (THE MOST IMPORTANT RULE)
Deep retrieval is the engine, not the product. The reader should never
feel like they're reading a research paper or a search results page.
The mirror must read like a brilliant essay by someone who knows the
reader deeply — not a report proving it did homework.
**The test:** If you remove all citations and source attributions, does
the mirror still make the reader feel seen? Does it still produce
epiphanies? Does it still work as standalone writing? If yes, the
retrieval served its purpose. If the mirror only works because of its
citations, the retrieval failed.
**Citations:** Optional. Use sparingly as footnotes when the source adds
genuine value ("you wrote this at 19" lands differently when the reader
knows you actually read the journal entry). But never let citations
become the point. Never let the mirror read like it's performing
thoroughness.
### Cross-modal eval gate (recommended for high-stakes mirrors)
After generating a mirror, run `gbrain eval cross-modal` (or the manual
gate in `skills/cross-modal-review/SKILL.md`) with these custom
dimensions:
- VARIETY (fresh each chapter?)
- SPECIFICITY (real stories/dates/quotes?)
- DEPTH (new insight vs restating profile?)
- LEFT_COLUMN_FIDELITY (preserves the book?)
- EMOTIONAL_RANGE (joy as well as struggle?)
```bash
gbrain eval cross-modal --slug <slug>-personalized \
--dimensions VARIETY,SPECIFICITY,DEPTH,LEFT_COLUMN_FIDELITY,EMOTIONAL_RANGE
```
Pass threshold: all dimensions average 7+ across models. If any dimension
is below 6, rebuild with targeted fixes. The eval→fix→re-eval cycle is the
quality multiplier. Evaluator model pairs and refusal routing follow
[conventions/cross-modal.yaml](../conventions/cross-modal.yaml).
### Children's book variant
For picture books and children's books (under ~5K words), use a
**Parent's Reading Guide** format instead of the standard mirror:
- The Chapter half: what the book says on each page/spread.
- The Mirror half: written FOR THE PARENT reading aloud — what each page
will feel like, what the child might ask at each age, what to say if
they do, and what the book is really teaching underneath the simple
words.
- Include: when to read it, how to handle specific reactions, and the
book's deeper structure mapped to developmental psychology research.
- Tone: warm, practical, specific to the reader's children by name and
age (from brain context).
Hand-assembled variants like this use the stacked-sections container.
## 4. Analysis: invoke `gbrain book-mirror`
```bash
gbrain book-mirror \
--chapters-dir "$WORK/chapters" \
--context-file "$CONTEXT" \
--slug "$SLUG" \
--title "Book Title Goes Here" \
--author "Author Name" \
--model claude-opus-4-7
```
The CLI:
- Validates inputs and loads chapter files.
- Prints a cost estimate (~$0.30/chapter at Opus) and prompts to confirm.
- Submits N child subagent jobs with read-only `allowed_tools`.
- Waits for every child to complete.
- Reads each child's `job.result` (the markdown analysis text).
- Assembles all chapters into one page with frontmatter + intro + per-chapter
sections + closing.
- Writes ONE `put_page` to `media/books/<slug>-personalized.md`.
- Reports a JSON envelope on stdout:
`{"slug": "...", "chapters_total": N, "chapters_completed": N, "chapters_failed": 0}`.
If any chapter failed, the CLI exits 1 and the user can re-run — idempotency
keys (`book-mirror:<slug>:ch-<N>`) deduplicate completed chapters at the
queue level, so retry is cheap. Note that reproducing verbatim book quotes
plus the reader's verbatim words can occasionally trip a provider output
filter; a chapter blocked that way is just a failed chapter — re-run, or
retry with a different `--model`.
### Model: Opus by default
The default model is `claude-opus-4-7`. Sonnet works (use `--model
claude-sonnet-4-6`) but the mirror quality drops noticeably — the
texture that makes the analysis feel like it was written by someone who
knows the reader needs Opus-grade reasoning.
### Cost gate
The CLI refuses to spend in a non-TTY context without `--yes`. CI / scripted
invocations must pass `--yes` explicitly. TTY users get a `[y/N]` prompt
before submission.
Deep retrieval raises total cost meaningfully versus a thin static
context pack (roughly an order of magnitude at Opus rates). The quality
jump is worth it for a book the reader cares about; use a static pack
only for low-stakes runs.
## 5. PDF (optional)
After the brain page is written (the CLI already did the `put_page`),
render to PDF using `skills/brain-pdf`:
```bash
# See skills/brain-pdf/SKILL.md for the invocation.
```
If the user asked for a deliverable, prefer the PDF over sending raw
markdown — the brain page is the source of truth; the PDF is the artifact
that travels.
## 6. Fact-check and cross-link
After the page lands, run a fact-check pass on factual claims about the
reader (parents, siblings, marriage history, jobs, heritage). Common error
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