generating-mod-envs

Generates and validates JSON learning envs for Letta Code mod behavior evaluation.

3.2k|385|Updated Oct 25, 2025
One-click install
npx skills add https://github.com/letta-ai/letta-code --skill generating-mod-envs
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: generating-mod-envs
Source: https://github.com/letta-ai/letta-code/tree/main/src/skills/builtin/generating-mod-envs
Command: npx skills add https://github.com/letta-ai/letta-code --skill generating-mod-envs

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) and assets (resource) components.

What problem does it solve?

Writing evaluation environments for Letta Code mod learning by hand is error-prone: envs must be strict JSON, distinguish real behavior from a no-op mod, and include negative controls. This Skill guides the design, drafting, and validation of mod learning env JSON files consumed by /mods learn --env.

Core Features & Use Cases

  • Env Authoring Guidance: Walks through defining the target mod behavior, choosing sentinel markers, and structuring evaluation.scenarios with happy-path, discrimination, and negative-control cases.
  • Template and Validation: Ships a starter template (assets/mod-learning-env.template.json) and a Bun validation script (scripts/validate-mod-env.ts) that checks required fields, marker arrays, memory fixtures, and scenario structure.
  • Use Case: You want to teach a local mod that registers a new tool. Use this Skill to draft an env with a happy-path scenario requiring a unique sentinel in the final answer, a negative control forbidding the tool call, and forbidden trace markers catching mod load failures, then validate it before running /mods learn.

Quick Start

Ask the agent to create and validate a mod learning env JSON for the behavior you want to teach, then run it with /mods learn --env=<path>.

Frequently Asked Questions about generating-mod-envs

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I create a mod learning env for /mods learn?

Define the target mod behavior, write strict JSON with name, slug, objective, requirements, and an evaluation block containing scenarios, then validate it with the bundled validate-mod-env.ts script before running /mods learn --env=<path>.

What scenarios should a mod learning evaluation include?

Include at least a happy-path scenario, a discrimination scenario with a tempting wrong sentinel, and a negative control verifying the mod stays silent when not triggered. Each scenario uses requiredResultMarkers and requiredTraceMarkers to make pass/fail unambiguous.

How do I validate a mod env JSON file?

Run bun scripts/validate-mod-env.ts path/to/env.json from the skill directory. The script checks required fields, marker arrays, memory file fixtures, and scenario structure, printing warnings for missing markers or non-kebab-case slugs.

Why does my mod learning eval pass a no-op mod?

The eval lacks discriminating markers. Add unique sentinel strings to requiredResultMarkers, include forbiddenTraceMarkers for load failures like "[mods] failed to load", and add a negative-control scenario so a placebo mod cannot pass.

Can I seed memory files for mod evaluation scenarios?

Yes, use evaluation.memoryFiles or per-scenario memoryFiles to seed files under the eval MEMORY_DIR with relative paths. This keeps fixtures self-contained instead of depending on real user memory or repo files.