arrey/tools/summarize

Summarizes text, files, and URLs into configurable formats. Handles long documents automatically through semantic chunking. This code is yours - edit it freely.

---

Usage

CLI

arrey summarize ./report.pdf
arrey summarize ./report.pdf --format executive
arrey summarize https://example.com/article --format tldr
arrey summarize "paste any text here" --format bullets
arrey summarize ./contract.pdf --format executive --instruction "Focus on liability clauses"

SDK

import { arrey } from 'arrey'

const result = await arrey.run('summarize', {
  content: './report.pdf',
  format: 'executive'
})

console.log(result.summary)

Direct import (tool-local helper)

import { summarize } from './arrey/tools/summarize'

const result = await summarize({
  prompt: './report.pdf',
  format: 'executive',
  temp: 0.4,
  model: 'gpt-4.1-mini'
})

console.log(result.summary)

Agent tool (Vercel AI SDK)

import { arrey } from 'arrey'
import { generateText } from 'ai'
import { openai } from '@ai-sdk/openai'
import { summarize } from './arrey/tools/summarize'

const { text } = await generateText({
  model: openai('gpt-4o'),
  tools: await arrey.toVercelAIFrom([summarize]),
  prompt: 'Summarize this report for me: ./q3-results.pdf'
})

Agent tool (LangChain)

const agent = await createReactAgent({
  llm: new ChatOpenAI(),
  tools: arrey.toLangChain(['summarize'])
})

---

Formats

Format	Output
bullets	5-7 bullet points. Default.
tldr	Single paragraph, under 100 words
executive	Structured: Overview, Key Points, Recommendation
custom	Whatever you define in prompt.ts -> formats.custom

---

Customization

Change bullet style

Edit prompt.ts -> formats.bullets. Example: change "5 to 7 bullet points" to "exactly 3 bullets" and "start each with a strong verb" to "start each with a number."

Add a custom format

Add a new key to prompt.ts -> formats:

formats: {
  ...existing formats,
  internal: `
    Format as an internal Slack update.
    Use casual language. Max 3 sentences.
    Start with: "Quick update:"
  `
}

Use it with: arrey summarize ./notes.txt --format internal

Make it domain-aware

Pass an instruction at call time - no code change needed:

arrey summarize ./legal.pdf --format bullets --instruction "Preserve all clause numbers and legal terms exactly."

Or hardcode it for your domain in prompt.ts -> chunk:

chunk: `
  You are summarizing part {{index}} of {{total}} of a legal document.
  Preserve all clause numbers, party names, and dollar amounts exactly.
  ...
`

Change chunking behavior

Edit index.ts -> the ctx.chunk() call:

const chunks = await ctx.chunk(content, {
  strategy: 'sentence',  // 'semantic' | 'fixed' | 'sentence' | 'code'
  maxTokens: 1500,       // smaller chunks = more API calls but more precise
  overlap: 100,          // reduce overlap for speed, increase for coherence
})

Use a different model for this tool only

Set it in arrey.config.yaml:

tools:
  summarize:
    model: gpt-4o   # override the default model just for this tool

---

Files

File	Purpose	Edit frequency
prompt.ts	All prompts and format definitions	Often
index.ts	Execution logic and chunking strategy	Sometimes
manifest.json	Tool metadata and I/O schema	Rarely
README.md	This file	Never (unless you want to)

---

How it handles long documents

1. Content is split into semantic chunks of ~2000 tokens with 200-token overlap
2. Each chunk is summarized independently (parallelized)
3. Partial summaries are combined into the final output using the format prompt
4. If there's only one chunk, the combine step is skipped entirely

This means the tool works on documents of any length - a tweet or a 500-page PDF.

---

Composes

This tool has no dependencies on other arrey tools. It is a primitive - other tools (like meeting-digest) call it internally.