Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/mpsuesser/pi-effect-harnessnpx agentmods add skills/mpsuesser/pi-effect-harness/effect-rpc-serverWrote 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.
[](https://agentmods.dev/skills/mpsuesser/pi-effect-harness/effect-rpc-server)<a href="https://agentmods.dev/skills/mpsuesser/pi-effect-harness/effect-rpc-server"><img src="https://agentmods.dev/badge/skills/mpsuesser/pi-effect-harness/effect-rpc-server.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00100 | $0.09354 |
| Opus 5 | $0.00050 | $0.04677 |
| Sonnet 5 | $0.00020 | $0.01871 |
| Haiku 4.5 | $0.00010 | $0.00935 |
Grade A, and why
effect-rpc-server scanned grade A with 1 finding 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 7d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
2. **Forgetting `protocol: 'http'` on `layerHttp`.** The default is `'websocket'` — your `POST /rpc` curl returns 404 and only a `GET` upgrade route exists. Also note `layerHttp` takes `{ group, path, ... }` as one optio How it starts
The opening of the file, as written. The whole thing — 752 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 serving RPC groups with RpcServer from effect/unstable/rpc.
Everything ships from the effect package under effect/unstable/rpc — there is no @effect/rpc package in v4. This skill covers the server side: implementing handlers, transports, serialization, middleware, and lifecycle. For defining Rpc/RpcGroup contracts see the effect-rpc-api skill; for building clients see the effect-rpc-client skill; for cluster entities see the effect-rpc-cluster skill; for HttpRouter/HttpServer fundamentals see the effect-http-server skill.
Effect Source Reference
The Effect v4 source is at ~/.cache/effect-v4/. Read it directly when in doubt — these modules change between betas.
Key files:
packages/effect/src/unstable/rpc/RpcServer.ts—make,makeNoSerialization,layer,layerHttp, everylayerProtocol*/makeProtocol*,toHttpEffect*, theProtocolservicepackages/effect/src/unstable/rpc/RpcGroup.ts—toLayer,toLayerHandler,toHandlers,accessHandler,of, handler type derivationpackages/effect/src/unstable/rpc/Rpc.ts—ServerClient,Handler,ToHandlerFn,ResultFrom,fork,uninterruptible,ServicesServerpackages/effect/src/unstable/rpc/RpcMiddleware.ts—Serviceconstructor, server middleware function shape,layerClientpackages/effect/src/unstable/rpc/RpcSerialization.ts—json,ndjson,jsonRpc,ndJsonRpc,msgPackparsers and their layerspackages/effect/src/unstable/rpc/RpcMessage.ts— the wire vocabulary (Request,Ack,Interrupt,Eof,Chunk,Exit,Defect,ClientEnd)packages/effect/src/unstable/rpc/RpcWorker.ts—InitialMessagefor worker transportspackages/effect/src/unstable/rpc/RpcTest.ts— in-process test clientpackages/effect/src/unstable/rpc/RpcSchema.ts—ClientAbortcause annotation, stream schema markerspackages/platform-node/test/RpcServer.test.ts+test/fixtures/rpc-{schemas,e2e}.ts— the best end-to-end reference for real wiring across http/ws/tcp transports and every serializationpackages/platform-browser/test/fixtures/rpc-worker.ts— minimal worker-side server entrypoint
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.
- 7d ago First seen · 752 lines · 100 tokens per session scan A a9ababd9f999
effect-rpc-server is a skill published in the GitHub repository mpsuesser/pi-effect-harness (24 stars, last pushed 2mo ago), licensed MIT. It adds 100 tokens to every session and 9,354 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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