Letta Code Mods

Official package source and public ecosystem curation for Letta Code mods.

Mods are executable local code that can add tools, slash commands, lifecycle events, permissions, providers, and UI surfaces to the Letta agent harness.

Warning

Mods run with the full permissions of the Letta Code process. Review package source and publisher provenance before installing any mod, including packages shown in the catalog.

Install a mod

Published packages install through Letta Code:

letta install npm:@letta-ai/plan-mode

Community packages use the same command with the publisher's npm package name:

letta install npm:@publisher/package

Git repositories are also supported:

letta install git:github.com/publisher/repository

Run /reload after installation.

Package discovery and ownership

The mods catalog discovers npm packages tagged with the letta-package keyword and GitHub repositories tagged with supported Letta mod topics. Package source does not need to live in this repository to appear in the catalog.

Catalog labels have separate meanings:

• Official packages are published and maintained by Letta.
• Community packages are published and maintained by their authors.
• Featured packages are selected by Letta for additional visibility. Featured is an editorial signal, not a security audit or ownership claim.

New community mods should live in author-owned repositories and npm scopes. New package source is accepted into this repository only when Letta explicitly adopts the package and commits to maintaining it.

Official packages

catalog/official.json is the public source of truth for official ownership. Every package under packages/ must appear in that allowlist, use the @letta-ai npm scope, and have an active Letta maintainer.

Official status is controlled by repository review. It is not inferred from npm scope or declared by package authors.

Featured packages

catalog/featured.json is the public source of truth for featured catalog placement. It contains typed npm-package or GitHub-repository sources in display order. Catalog consumers overlay this list on top of normal registry and topic discovery.

A featured package may be official or community-maintained. Catalog consumers preserve the ownership label independently from the Featured badge.

Changes to the featured list are reviewed like code changes. See CONTRIBUTING.md for nomination criteria.

Retired packages

catalog/retired.json records packages removed from official maintenance, the original contributor, and the pull request that introduced the source. A replacement is listed only after an owner-maintained package or repository exists.

Existing retired npm releases remain available for migration compatibility. They are not part of the official allowlist and receive no new releases from this repository.

Repository structure

catalog/
├── featured.json          # Editorial selection and ordering
├── official.json          # Letta-maintained package allowlist
└── retired.json           # Community migration records
packages/
└── <package>/             # Letta-published mod package source
scripts/
├── validate-catalog.mjs   # Catalog policy and package ownership validation
└── validate-manifests.mjs # Package manifest validation

The duplicated hand-maintained package indexes that previously lived in this README were removed. Package metadata belongs in each package's package.json, while the catalog is generated from registry metadata.

Mod package format

A published mod package should include:

package.json  # npm metadata and package.json#letta manifest
README.md     # user-facing documentation
MOD.md        # agent-facing semantics and adaptation notes
mods/         # implementation files declared by package.json#letta

Example manifest:

{
  "name": "@publisher/example-mod",
  "keywords": ["letta-package", "letta-mod"],
  "letta": {
    "manifestVersion": 1,
    "mods": ["./mods/index.ts"],
    "capabilities": ["commands"]
  }
}

README.md is for people browsing GitHub, npm, or the catalog. MOD.md helps agents inspect package behavior, safety assumptions, and adaptation points.

Development

Clone the repository and run its validation suite:

git clone https://github.com/letta-ai/mods.git
cd mods
npm run validate

See CONTRIBUTING.md before proposing package source or featured-list changes.

Recovery

If a mod breaks startup or command handling, start Letta Code with mods disabled:

letta --no-mods
# or
LETTA_DISABLE_MODS=1 letta

Then remove or repair the package and run /reload.

Security vulnerabilities should be reported privately according to SECURITY.md.

Links

• Letta Code
• Letta Code documentation
• Mods catalog
• Letta skills repository