KernelsWatch one write, line by line→Letterwrite · CLI-ready writing harnesses · Adversarial by design

Letterwrite provides primitive writing kernels that adversarially produce good writing from a prompted source-of-truth. Designed for developers, built for content marketing.

Seed prompt · Shredded across dozens of models · Adversarially reviewed

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draft.md· kernel sequoia · 12 reviewersdrafting…
Brief · settling-the-mcp-vs-cli-debate

Settling the MCP vs. CLI debate

In today’s fast-paced world, the choice has never mattered more.
An MCP server hands an agent typed tools and a schema it can trust.
Let’s delve into the rich tapestry of trade-offs.
The real question is where your users already work.
… words3 models on this draft
Adversarial council
00/ 07 recursions
reads as human0 / 12
letterwrite — zsh
$letterstory write --brief "./settling-the-mcp-vs-cli-debate.mdx" --kernel sequoia
✓kernel sequoia · 12 models0.6s
✓draft · adversarial vote, line by line8.4s
→draft.md · 1,240 words · on-voice
$letterstory shred draft.md
✓rewrote across 34 models3.1s
$
Watch it write

Writing kernels facilitate a four-step process

LLMs produce contrived writing. Writing kernels counteract that by providing the right harness for producing writing that feels human.

  1. 01

    It starts from a seed prompt.

    All kernels start with a seed prompt to help shape writing into its flavor.

  2. 02

    It’s shredded across models.

    The produced writing is shredded across dozens of models to prevent watermarks and single-model reliance.

  3. 03

    It’s held to test cases.

    Writing is tested against common test cases. When violated, writing is workshopped within a degree of freedom.

  4. 04

    A council asks: AI or human?

    A council of agents determines if the writing is AI or human. When failed, the kernel recurses to step 2 with feedback.

brief · kernel sequoia
Seed prompt
voice plainspokenaudience developerskernel sequoiasource ./brief.mdx
Shredder 0 / 34 models
Test cases 0 / 4 run
  • No throat-clearing opener
  • No “delve”, “tapestry”, “pivotal”
  • One idea per sentence
  • No reflexive lists of three
Adversarial council 0 / 12 read it as human
00
↳ draft.md · 1,240 words · passed after 7 recursions

On average, kernels take seven recursions to converge. The approximate computation time is 35 minutes for a 1,500-word article.

Try it

Drag a draft through seven recursions

Recursion one is what a single model hands you. Every pass after it, the council catches something, and the kernel rewrites exactly that.

draft.md · paragraph 1

In today’s fast-paced digital landscape, choosing the right tooling is more important than ever. Let’s delve into the rich tapestry of trade-offs that shape this pivotal decision. It’s about speed, flexibility, and scalability. It’s not just a technical choice, but a strategic one. Many teams find that MCP offers significant benefits. Ultimately, the best choice depends on your unique needs.

Recursion
01/ 07

DraftA single model’s first draft. No review yet.

reviewers who read it as human2 / 12
01 · single modelkernel · 07
Post-training & shredding

Tuned to your voice, blended across dozens of models

An off-the-shelf kernel is a strong starting point, but it is not a ceiling.

Kernels can be refined

Refine kernels by ingesting the voice that you want to imitate. Feed it your corpus: past posts, brand guidelines, subject-matter docs, your best-performing pages. Then post-train the kernel on that material so its judgments converge on style.

  1. 01posts/why-we-rewrote-our-cli.mdvoice
  2. 02brand/style-guide.pdfrules
  3. 03docs/api-reference/*.mdxfacts
  4. →kernel sequoia · post-trainedyour voice

A shredder inside, drawing on dozens of models

Every kernel ships with a shredder that blends dozens of models to avoid a single model’s watermark. You can also use shredders directly via Lettershred.

one draft34 models · no single watermark

Hotswap Claude and GPT for a writing kernel.

Writing kernels take only 2 minutes to set up. Mint a key and start today.