effect-ts-everywhere

A coding rule for ClawQL projects that requires Effect-TS for production code whenever the work can use it. Effect-TS is a TypeScript library and programming style for structuring errors, dependencies, and workflows.

In plain words
What is it for?
It guides how to write database, network, file, configuration, crypto, orchestration, and multi-step workflow code, including when a small Promise wrapper is allowed.
Why use it?
It keeps domain code consistent instead of mixing ordinary functions and Effect-based code. It also limits Promise-based code to thin host-specific wrappers such as server handlers.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/danielsmithdevelopment/clawql/effect-ts-everywhere
Clone the repo
git clone --depth 1 https://github.com/danielsmithdevelopment/ClawQL

Made for: Cursor.

Per session 428 This file is loaded in full into every session.
When invoked 428 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00428 $0.00428
Opus 5 $0.00214 $0.00214
Sonnet 5 $0.00086 $0.00086
Haiku 4.5 $0.00043 $0.00043

Measured 2d ago against content hash 7efa7698ff95, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

effect-ts-everywhere scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/effect-ts-everywhere.mdc · 34 lines

What it actually says

Effect-TS everywhere (hard rule)

ClawQL production code that can be Effect-based must be Effect-based. There is no “pure sync is fine” exception and no standing exception for Promise domain APIs.

Must be Effect

  • Domain IO (fs, net, DB, crypto that participates in workflows)
  • Orchestration, policy gates, config reads used by domain code
  • URL/HTML builders, sync crypto helpers, env flag readers — expose as Effect (Effect.sync / Effect.succeed / service methods), not bare functions returning plain values as the primary API
  • Multi-step workflows — Effect.gen + Context.Tag / Layer

Only exception: forced host boundary

Express handlers, MCP server.tool callbacks, and similar hosts that literally require a Promise return may use a thin async façade whose entire body is Effect.runPromise / run*Effect / ManagedRuntime. No business logic in the façade.

Types-only modules (interfaces, type aliases) are not executable code and need no Effect wrapper.

Never ship

  • Bare async / Promise as the primary API of a domain module
  • Bare sync functions as the primary API when the same work can be Effect.sync / a Tag method
  • Docs that carve out “pure sync” or “legacy async at IO edges” as acceptable defaults
  • Growing Promise façades “for convenience” when callers can yield* or Effect.runPromise a service

Required shape

  • Prefer Context.Tag + Layer with methods returning Effect.Effect<A, E, R>
  • Absolute external IO (fs/fetch/SDK) only via Effect.tryPromise / *FromPromise inside Effect programs
  • Tests use Layers / Effect.provide — do not invent Promise-only domain APIs for tests

Reviewer checklist

Reject if a changed executable domain export is not Effect-based and is not a documented one-line forced-host façade.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 34 lines · 428 tokens per session scan A 7efa7698ff95

Subscribe to this mod's changes

effect-ts-everywhere is a cursor rule published in the GitHub repository danielsmithdevelopment/ClawQL (12 stars, last pushed 3d ago), licensed Apache-2.0. It adds 428 tokens to every session, about $0.0021 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.