effect-rpc-client

effect-rpc-client is a skill for Claude Code, Codex from mpsuesser/pi-effect-harness. It costs 88 tokens per session (8,916 once invoked), scanned A, original, MIT.

A guide for using typed remote procedure call services from an Effect client. It covers how a client connects to another program over transports such as HTTP, WebSocket, TCP, workers, or an in-memory connection.

In plain words
What is it for?
Use it to build RPC clients, select a transport and data format, attach headers, consume streaming calls, reconnect, and handle client-side failures.
Why use it?
It reduces mismatches between client calls and server contracts and provides defined handling for headers, streams, interruptions, reconnections, and RPC errors.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to build RPC clients, select a transport and data format, attach headers, consume streaming calls, reconnect, and handle client-side failures.

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Install with agentmods
npx agentmods add skills/mpsuesser/pi-effect-harness/effect-rpc-client
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.

Any agent
npx skills add mpsuesser/pi-effect-harness --skill effect-rpc-client
Clone the repo
git clone --depth 1 https://github.com/mpsuesser/pi-effect-harness

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for effect-rpc-client

README.md
[![agentmods](https://agentmods.dev/badge/skills/mpsuesser/pi-effect-harness/effect-rpc-client.svg)](https://agentmods.dev/skills/mpsuesser/pi-effect-harness/effect-rpc-client)
Your own site
<a href="https://agentmods.dev/skills/mpsuesser/pi-effect-harness/effect-rpc-client"><img src="https://agentmods.dev/badge/skills/mpsuesser/pi-effect-harness/effect-rpc-client.svg" alt="Measured on agentmods" height="20"></a>
Per session 88 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 8,916 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00088 $0.08916
Opus 5 $0.00044 $0.04458
Sonnet 5 $0.00018 $0.01783
Haiku 4.5 $0.00009 $0.00892

Measured 8d ago against content hash 09e6886587e6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

effect-rpc-client 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 8d 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.

harnesses/effect/skills/effect-rpc-client/SKILL.md · 660 lines

How it starts

The opening of the file, as written. The whole thing — 660 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an Effect TypeScript expert specializing in consuming RPC services with RpcClient from effect/unstable/rpc.

This skill covers the client side only: building clients, transports, serialization, headers, streaming consumption, interruption, errors, and testing. Defining Rpc/RpcGroup contracts is the effect-rpc-api skill; serving them is the effect-rpc-server skill; cluster entity clients are the effect-rpc-cluster skill.

Effect Source Reference

The Effect v4 source is at ~/.cache/effect-v4/. Read it directly when in doubt — these modules are under unstable and change between betas.

Key files:

  • packages/effect/src/unstable/rpc/RpcClient.tsmake, makeNoSerialization, the Protocol service, layerProtocolHttp/layerProtocolSocket/layerProtocolWorker (+ makeProtocol*), CurrentHeaders, withHeaders, ConnectionHooks
  • packages/effect/src/unstable/rpc/RpcClientError.tsRpcClientError and RpcClientDefect
  • packages/effect/src/unstable/rpc/RpcSerialization.tsjson, ndjson, jsonRpc, ndJsonRpc, msgPack codecs, their layers, the Parser interface and includesFraming
  • packages/effect/src/unstable/rpc/RpcTest.tsmakeClient in-process test client
  • packages/effect/src/unstable/rpc/RpcWorker.tsInitialMessage, layerInitialMessage, initialMessage
  • packages/effect/src/unstable/rpc/RpcMessage.ts — wire vocabulary: Request, Ack, Interrupt, Chunk, Exit, Defect, Ping/Pong, ClientProtocolError, RequestId
  • packages/effect/src/unstable/socket/Socket.tsSocket service, layerWebSocket, WebSocketConstructor
  • packages/platform-node/test/RpcServer.test.ts + test/fixtures/rpc-e2e.ts + test/fixtures/rpc-schemas.ts — the best end-to-end reference: every transport × serialization combination, headers, streams, interrupts, defects
  • packages/platform-browser/test/RpcWorker.test.ts + test/fixtures/rpc-worker.ts — worker transport end to end

Core Model

A client is assembled from three replaceable layers plus your shared RpcGroup definition:

Read the full file on GitHub · 660 lines

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. 8d ago First seen · 660 lines · 88 tokens per session scan A 09e6886587e6

Subscribe to this mod's changes

effect-rpc-client is a skill published in the GitHub repository mpsuesser/pi-effect-harness (24 stars, last pushed 2mo ago), licensed MIT. It adds 88 tokens to every session and 8,916 once invoked, about $0.0004 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.