goa-ai CLAUDE.md

goa-ai CLAUDE.md is an instructions file for coding agents from goadesign/goa-ai. It costs 916 tokens per session, scanned A, original, MIT.

Repository instructions for generating an MCP interface from Goa services. MCP is a standard way for AI agents to access tools and resources.

In plain words
What is it for?
Use them when developing or generating the goadesign/goa-ai MCP plugin, especially when mapping service methods to MCP tools, resources, or prompts.
Why use it?
They define the expected files, paths, mappings, and errors, reducing accidental rewrites or incomplete generated output.

Instructions file

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 instructions/goadesign/goa-ai/claude-md
Clone the repo
git clone --depth 1 https://github.com/goadesign/goa-ai

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 goa-ai CLAUDE.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/goadesign/goa-ai/claude-md.svg)](https://agentmods.dev/instructions/goadesign/goa-ai/claude-md)
Your own site
<a href="https://agentmods.dev/instructions/goadesign/goa-ai/claude-md"><img src="https://agentmods.dev/badge/instructions/goadesign/goa-ai/claude-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 916 This file is loaded in full into every session.
When invoked 916 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 $0.00916 $0.00916
Opus 5 $0.00458 $0.00458
Sonnet 5 $0.00183 $0.00183
Haiku 4.5 $0.00092 $0.00092

Measured 4d ago against content hash 8874f611dc61, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

goa-ai CLAUDE.md 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 4d 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.

CLAUDE.md · 85 lines

How it starts

The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE Guide for MCP Plugin (Goa)

This file guides Claude when working on this repo. It captures intent, guardrails, and how to run generation. Read this first.

High-level goals

  • Treat MCP as a transport layered on top of Goa services.
  • Generate an MCP-facing surface by composing on Goa codegen (don’t fork).
  • Prefer small, deterministic transformations over big rewrites.
  • Keep the output paths/imports aligned with Goa conventions.

Core strategy (from prompts.txt)

  • Assume services that use the plugin are pure MCP by default.
    • If any service method is not mapped to an MCP construct (tool, resource, prompt), fail generation with a clear error.
    • Filter away original transport files we no longer need (HTTP, gRPC, plain JSON-RPC) while keeping the essentials:
      • Service interface, endpoints, types
      • Encode/decode bits needed to unmarshal/marshal MCP payloads/results (reusing json.RawMessage tricks)
  • Build an in-memory MCP service expression and let Goa generate service + JSON-RPC transport.
  • Reuse Goa’s encoding/decoding to map MCP payloads to original payload types and vice versa for results.
  • Apply minimal post-processing:
    • Move JSON-RPC files to gen/jsonrpc/mcp/<service>/...
    • Duplicate HTTP client paths to gen/http/mcp/<service>/client/paths.go
    • Update header imports/titles (modeled after Goa’s updateHeader).
  • Ensure both server and client (and their CLIs) expose only MCP endpoints.

File/dir conventions

  • Service layer: as Goa generates it (kept intact).
  • JSON-RPC transport for MCP: gen/jsonrpc/mcp/<service>/...
  • HTTP path files for MCP clients: gen/http/mcp/<service>/client/paths.go
  • Avoid contextual names like mcp_direct.go. Follow Goa naming patterns.

Path handling

  • Always use codegen/pathutil.go helpers (normalize, replaceFirst, join).
  • No ad-hoc ToSlash/FromSlash in generation logic.

Streaming

  • Do not author custom MCP streaming templates.
  • Rely on Goa JSON-RPC codegen for SSE/WebSocket when methods stream, then relocate/retitle.

Read the full file on GitHub · 85 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. 4d ago First seen · 85 lines · 916 tokens per session scan A 8874f611dc61

Subscribe to this mod's changes

goa-ai CLAUDE.md is an instructions file published in the GitHub repository goadesign/goa-ai (8 stars, last pushed today), licensed MIT. It adds 916 tokens to every session, about $0.0046 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 2026-08-31.