borsdata-mcp-server: Instructions file for Claude Code

CLAUDE.md

borsdata-mcp-server CLAUDE.md is an instructions file for Claude Code from carlwestman/borsdata-mcp-server. It costs 1,376 tokens per session, scanned A, original, MIT.

A set of project instructions for Claude Code, an AI coding assistant, while working on a TypeScript server that exposes Borsdata financial data through MCP, a standard way for AI tools to use external tools.

In plain words
What is it for?
Use it when building, running, testing, linting, or changing the Borsdata MCP server. It also explains where the API client, rate limiter, data types, and tool registrations are located.
Why use it?
It gives the assistant the project layout, commands, architecture, required API key, and testing conventions so it can work within the repository correctly.

Instructions file for Claude Code

Written for Claude Code: the file is CLAUDE.md. Also seen: mentions CLAUDE.md; mentions Claude Code.

This is carlwestman/borsdata-mcp-server's own configuration. It tells Claude Code how to work on borsdata-mcp-server 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 borsdata-mcp-server configures →

Reuse

Borrowing it

Nothing to install: this file belongs to carlwestman/borsdata-mcp-server. 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/carlwestman/borsdata-mcp-server/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/carlwestman/borsdata-mcp-server

Made for: Claude Code.

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README.md
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Per session 1,376 This file is loaded in full into every session.
When invoked 1,376 The same file — it is already loaded in full.
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 $0.01376 $0.01376
Opus 5 $0.00688 $0.00688
Sonnet 5 $0.00275 $0.00275
Haiku 4.5 $0.00138 $0.00138

Measured 6d ago against content hash d8723d796c69, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

borsdata-mcp-server 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 6d 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 · 132 lines

How it starts

The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

Project Overview

MCP (Model Context Protocol) server that exposes the Borsdata financial data API as tools for Claude. Built with TypeScript using @modelcontextprotocol/sdk (McpServer + StdioServerTransport).

Build & Run

npm install           # Install dependencies
npm run build         # Compile TypeScript to dist/
npm run dev           # Run with tsx (development)
npm start             # Run compiled dist/index.js
npm test              # Run tests (vitest)
npm run lint          # Lint (eslint)

Requires BORSDATA_API_KEY environment variable.

Architecture

src/
  index.ts              # Server entry point — creates McpServer, registers tools + resources, connects stdio
  api/
    client.ts           # BorsdataClient — typed HTTP wrapper for all Borsdata API endpoints
    rate-limiter.ts     # Sliding window rate limiter (100 calls / 10 seconds)
    types.ts            # TypeScript interfaces for all API response shapes
  tools/                # One file per domain, each exports a register function
    instruments.ts      # search_instruments, search_global_instruments, list_instruments, list_global_instruments, get_instrument_descriptions
    stock-prices.ts     # get_stock_prices, get_stock_prices_batch, get_latest_prices, get_latest_prices_global, get_prices_by_date, get_prices_by_date_global
    reports.ts          # get_reports, get_all_reports, get_reports_batch
    kpi-screener.ts     # get_kpi, get_kpi_all, get_kpi_updated
    kpi-history.ts      # get_kpi_history, get_kpi_history_batch, get_kpi_summary
    holdings.ts         # get_insider_holdings, get_short_positions, get_buybacks (Pro+)
    calendar.ts         # get_report_calendar, get_dividend_calendar
    meta.ts             # list_branches, list_countries, list_markets, list_sectors
    stock-splits.ts     # get_stock_splits
  resources/            # MCP Resources — knowledge base for Claude to look up opaque IDs
    index.ts            # Registers all resources
    api-guide.ts        # Static: API overview, workflows, parameter reference
    kpi-metadata.ts     # Dynamic (cached): KPI ID → name lookup table from API
    report-metadata.ts  # Dynamic (cached): report field name mappings from API
  utils/
    errors.ts           # BorsdataError class + toolError() helper for structured error responses

Read the full file on GitHub · 132 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. 6d ago First seen · 132 lines · 1,376 tokens per session scan A d8723d796c69

Subscribe to this mod's changes

borsdata-mcp-server CLAUDE.md is an instructions file published in the GitHub repository carlwestman/borsdata-mcp-server (0 stars, last pushed 5mo ago), licensed MIT. It adds 1,376 tokens to every session, about $0.0069 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.

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