Feature Flags Rust — Agent Skill by PostHog

From the author

PostHog feature flags for Rust applications

— the description by PostHog

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides guidance and best practices for implementing PostHog feature flags within Rust-based applications. It emphasizes server-side evaluation for performance and consistency, while providing architectural patterns to keep flag logic clean and maintainable. The skill also covers integration with PostHog MCP tools to manage flag lifecycles directly from your development environment.

What it does

Provides patterns for integrating PostHog feature flags into Rust codebases.
Offers best practices for flag naming, targeting, and lifecycle management.
Supports server-side flag evaluation to minimize UI flicker and latency.
Facilitates management of feature flags via PostHog MCP tools.
Encourages clean code by wrapping flag checks in reusable functions.

When to use it

When you need to perform canary releases or feature rollouts in a Rust application.
When you want to run A/B tests or experiments on server-side logic.
When you need to manage feature flags programmatically using MCP tools.
When you want to ensure consistent user experiences across sessions by identifying users correctly.

Advantages

Reduces code clutter by promoting centralized flag check functions.
Improves performance through server-side local evaluation.
Enhances maintainability with clear naming conventions and structured flag usage.
Enables direct flag management from the development environment via MCP.

Usage examples

“How do I implement a boolean feature flag in my Rust service?”: The agent will provide a code pattern for checking a flag key and executing conditional logic, while advising on the use of environment variables for configuration.
“Can you help me manage my PostHog feature flags using MCP?”: The agent will check for a connected PostHog MCP server and guide you through using available tools to list, update, or create flags without leaving your IDE.

Install

Download the skill as a ZIP:
https://autogineer.com/agent-skills/posthog/feature-flags-rust/download

Unzip it into the cross-client skills folder of your project:

mkdir -p .agents/skills && unzip feature-flags-rust.zip -d .agents/skills

Documentation by PostHog

PostHog feature flags for Rust

This skill helps you add PostHog feature flags to Rust applications.

Reference files

references/rust.md - Rust feature flags installation - docs
references/adding-feature-flag-code.md - Adding feature flag code - docs
references/best-practices.md - Feature flag best practices - docs

Consult the documentation for API details and framework-specific patterns.

Key principles

Environment variables: Always use environment variables for PostHog keys. Never hardcode them.
Minimal changes: Add feature flag code alongside existing logic. Don't replace or restructure existing code.
Boolean flags first: Default to boolean flag checks unless the user specifically asks for multivariate flags.
Server-side when possible: Prefer server-side flag evaluation to avoid UI flicker.

PostHog MCP tools

Check if a PostHog MCP server is connected. If available, look for tools related to feature flag management (creating, listing, updating, deleting flags). Use these tools to manage flags directly in PostHog rather than requiring the user to do it manually in the dashboard.

Framework guidelines

No specific framework guidelines.

Files

ATTRIBUTION.mdAdded by AutoGineer954 B
LICENSELicence file added by AutoGineer1.0 KiB
SKILL.md1.3 KiB
references/adding-feature-flag-code.md108.7 KiB
references/best-practices.md7.9 KiB
references/rust.md4.3 KiB

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs an MCP server

Security

No issues found by our static scan· No issues found

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

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