Side Letter

Q: What is a Claude Code skill and how does the Side Letter skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Side Letter is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Dev Tools category. Learn more at https://claudskills.com/learn/what-is-skill-md/.

Category: Dev Tools · Sub-category: ide-editor · Last updated: 2026-06-06

Drafts U.S. venture capital and private equity side letter agreements that supplement a primary agreement without formal amendment. Use when drafting a side letter, supplemental letter, investor side letter, MFN carve-out, or special-rights letter tied to an existing agreement.

About this skill (catalog notes)

Side Letter includes at least one code block. The SKILL.md runs to about 848 words, in the catalog's typical mid-range.

License: Apache-2.0
Original author: CaseMark
Indexed lastmod: 2026-06-06
Catalog position: Dev Tools · ide-editor
Indexed related skills: 10

How Side Letter fits the catalog

Side Letter sits in the Dev Tools category under the ide-editor sub-topic in the ClaudSkills catalog. There are 10 related skills indexed alongside it; comparing a few before installing usually reveals which fits your workflow best.

These notes are auto-generated from features detected in the SKILL.md file and from this catalog's structure — they aren't part of the source repository.

From the source SKILL.md

Drafts a supplemental agreement that modifies or clarifies a primary agreement while preserving its structure. Commonly used in VC/PE transactions for investor-specific rights, waivers, and MFN carve-outs.

What this skill does

Side Letter is a community-contributed Claude Code skill in the ide-editor sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/side-letter/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when drafting a side letter, supplemental letter, investor side letter, MFN carve-out, or special-rights letter tied to an existing agreement.

Who uses this skill

The Side Letter Claude Code skill is built for developers, power users, and teams automating repetitive workflows and improving developer experience. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 93,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/side-letter
curl -L https://claudskills.com/skills/side-letter/SKILL.md \
  -o ~/.claude/skills/side-letter/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/side-letter/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/side-letter/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\side-letter\SKILL.md on Windows. See the full install guide for step-by-step instructions.

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Side Letter Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/side-letter/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.

What does the Side Letter skill do?

Is this skill free to install?

Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.

When should I use the Side Letter skill?

Use Side Letter when your Claude Code task falls under the Dev Tools category — specifically in the ide editor area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Side Letter" or describe the task and let Claude pick). Browse related skills at /category/tools/.

What is a Claude Code skill and how does the Side Letter skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Side Letter is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Dev Tools category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Source: https://github.com/ThomasMoreAI/legal-skills-open/blob/HEAD/us/finance/skills/side-letter/SKILL.md
License: Apache-2.0
Author: CaseMark

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA

CaseMark. (2026). Side Letter [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/side-letter/

BibTeX

@misc{side-letter-2026,
  author    = {CaseMark},
  title     = {Side Letter [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/side-letter/}
}

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