What effector is, why it exists, and how it fits into the AI agent landscape.

Overview

Effector is the standard toolkit for typed AI agent tool interoperability. It adds a typed interface layer to AI agent tools โ€” 40 standard capability types, static composition checking, and cross-runtime compilation from a single sidecar manifest.

AI agent capabilities are in the pre-TypeScript era. effector-types is the lib.d.ts for Effectors โ€” the standard library of capability types grounded in real-world usage from 13,000+ analyzed tools.

The Problem

Every AI agent tool has an implicit interface: it takes something, produces something, and needs something from the environment. But today, these interfaces are invisible. The consequences:

  • Composition by prayer. You chain two MCP tools and discover at runtime that they're incompatible โ€” after burning tokens, time, and API calls.
  • Runtime lock-in. MCP tools only work in MCP. LangChain tools only work in Python. Your capability definitions are trapped in one ecosystem.
  • Discovery by keyword. Finding a tool that produces ReviewReport from CodeDiff requires reading READMEs, not querying a type catalog.
  • Implicit security. Whether a tool accesses the network or filesystem is buried in implementation, not declared in metadata.

The Solution

Effector adds a typed interface layer to AI agent tools. It's a sidecar manifest โ€” your tool keeps running exactly as before. Drop an effector.toml next to your tool:

Now your tool has:

  1. Type-safe interfaces โ€” input/output/context from 40 standard capability types
  2. Static composition checking โ€” verify tool chains before execution
  3. Cross-runtime portability โ€” compile to MCP, OpenAI, LangChain, or JSON
  4. Security auditing โ€” declared permissions vs actual behavior

How It Compares

FeatureRaw MCPLangChainCrewAIeffector
Type safetyNoneNoneNone40 standard types
CompositionManualRuntime onlyRigid rolesStatic verification
Cross-runtimeMCP onlyPython onlyPython onlyMCP, OpenAI, LangChain, JSON IR
DiscoveryBy nameBy nameBy nameBy input/output type
DependenciesVariesHeavyHeavyZero
Permission modelNoneNoneNoneDeclared + audited
Existing toolsN/ARewriteRewriteUnchanged (sidecar)

The Toolchain

effector is a cohesive ecosystem of focused tools, each doing one thing well:

ToolWhat it does
@effectorhq/coreShared kernel โ€” TOML parser, type checker, schema validator, compiler
create-effectorScaffold new capabilities in seconds with interactive prompts
@effectorhq/skill-lintValidate SKILL.md structure, frontmatter, and section coverage
@effectorhq/auditSecurity analysis โ€” permission mismatches, undeclared access, trust scores
@effectorhq/composeStatic pipeline builder โ€” verify type compatibility between tools
@effectorhq/graphInteractive dependency graph (D3 force layout, spectrum, dashboard)
@effectorhq/skill-evalQuality scoring (0-100) across 10 weighted dimensions
effector-studioVisual editor for building manifests with compile target preview

Architecture

effector.toml + SKILL.md  (your capability definition)
        โ”‚
        โ”œโ”€โ”€ validate  โ†’  schema validator + type checker
        โ”œโ”€โ”€ lint      โ†’  SKILL.md structure checks
        โ”œโ”€โ”€ audit     โ†’  permission + trust analysis
        โ”œโ”€โ”€ compose   โ†’  type-based pipeline verification
        โ”œโ”€โ”€ compile   โ†’  MCP / OpenAI / LangChain / JSON IR
        โ””โ”€โ”€ graph     โ†’  dependency visualization

All tools share @effectorhq/core as a kernel. Every module uses only Node.js built-ins โ€” zero external dependencies, zero supply chain risk.

Next Steps