finnhub-mcp: Instructions file for Claude Code

CLAUDE.md

finnhub-mcp CLAUDE.md is an instructions file for Claude Code from SalZaki/finnhub-mcp. It costs 5,238 tokens per session, scanned A, original, MIT.

A set of instructions for AI coding agents working on finnhub-mcp, a C# server that provides financial data from Finnhub through compatible assistants.

In plain words
What is it for?
It helps agents build and test the server, run it over HTTP or standard input and output, and follow its project structure.
Why use it?
It gives agents the repository’s build, test, formatting, running, and architecture rules in one place.

Instructions file for Claude Code

Written for Claude Code: the file is CLAUDE.md. Also seen: reads .claude/ paths; mentions CLAUDE.md; mentions Claude Code.

This is SalZaki/finnhub-mcp's own configuration. It tells Claude Code how to work on finnhub-mcp itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything finnhub-mcp configures →

Reuse

Borrowing it

Nothing to install: this file belongs to SalZaki/finnhub-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/SalZaki/finnhub-mcp/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/SalZaki/finnhub-mcp

Made for: Claude Code.

Wrote this? Show the measurements

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Per session 5,238 This file is loaded in full into every session.
When invoked 5,238 The same file — it is already loaded in full.
Security scan A 1 finding. 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 $0.05238 $0.05238
Opus 5 $0.02619 $0.02619
Sonnet 5 $0.01048 $0.01048
Haiku 4.5 $0.00524 $0.00524

Measured 11d ago against content hash 7f56b78f4374, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

finnhub-mcp CLAUDE.md 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 11d 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.

9. **MANDATORY: live-smoke against real Finnhub** with the running server before marking the PR ready. `dotnet run` locally, hit each new tool via curl or Claude Code, confirm the response shape. Mocks alone don't catch
CLAUDE.md · 240 lines

How it starts

The opening of the file, as written. The whole thing — 240 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

Guidance for AI coding agents Claude Code, Cursor, etc. working in this repository.

Project overview

finnhub-mcp is a Model Context Protocol (MCP) server, built on the official ModelContextProtocol C# SDK, that exposes Finnhub's financial-data APIs to MCP-compatible clients (Claude Desktop, IDE assistants, agents). The server supports HTTP and STDIO transports and follows Clean Architecture across three projects.

Build, test, format

dotnet build                                  # build all projects
dotnet test                                   # run all xUnit test projects
dotnet test --settings coverlet.runsettings   # tests with coverage
dotnet format                                 # apply formatting + analyzers
dotnet watch --project src/FinnHub.MCP.Server # hot reload (HTTP transport)

TreatWarningsAsErrors is enabled in Directory.Build.props - any analyzer or compiler warning fails the build. Don't suppress warnings; fix them.

Running locally

dotnet run --project src/FinnHub.MCP.Server                  # HTTP on :8080
dotnet run --project src/FinnHub.MCP.Server -- --stdio       # STDIO transport

The Finnhub API key is read from the FINNHUB_API_KEY environment variable, or from dotnet user-secrets (FinnHub:ApiKey) in Development. A legacy .env (loaded by DotNetEnv in Development) is still honoured as a fallback, but it is git-ignored and a pre-commit hook blocks it from being staged. Never hardcode the key or commit .env.

Project layout

src/
├── FinnHub.MCP.Server/                # ASP.NET Core host, MCP transport, Tools, Resources
├── FinnHub.MCP.Server.Application/    # Domain models, queries, services, exceptions
└── FinnHub.MCP.Server.Infrastructure/ # Finnhub HTTP client, DTOs, JSON context, DI
tests/
├── FinnHub.MCP.Server.Application.Tests.Unit/
├── FinnHub.MCP.Server.Infrastructure.Tests.Unit/
└── FinnHub.MCP.Server.Tests.Unit/

Dependency direction: ServerApplicationInfrastructure. The Application project must not reference Server or Infrastructure.

Read the full file on GitHub · 240 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. 11d ago First seen · 240 lines · 5,238 tokens per session scan A 7f56b78f4374

Subscribe to this mod's changes

finnhub-mcp CLAUDE.md is an instructions file published in the GitHub repository SalZaki/finnhub-mcp (5 stars, last pushed 3d ago), licensed MIT. It adds 5,238 tokens to every session, about $0.0262 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 2026-08-31.

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