What is financial-data CLAUDE.md?

Project instructions for a FastAPI service that provides stock-market information through REST APIs. It describes the code structure, development commands, dependencies, and use of Yahoo Finance data.

Use it when developing, debugging, or running this project, especially its API endpoints, data models, utilities, and market-data integration.

It gives coding agents the repository-specific context needed to modify or run the financial-data service correctly.

How aostock/financial-data configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to aostock/financial-data. 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/aostock/financial-data/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/aostock/financial-data

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/aostock/financial-data/claude-md/github.svg)](https://agentmods.dev/instructions/aostock/financial-data/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/aostock/financial-data/claude-md"><img src="https://agentmods.dev/badge/instructions/aostock/financial-data/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/aostock/financial-data/claude-md"><img src="https://agentmods.dev/badge/instructions/aostock/financial-data/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 495 This file is loaded in full into every session.

When invoked 495 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.

Model	Per session	Once invoked
Fable 5.1	$0.00495	$0.00495
Opus 5.5	$0.00198	$0.00198
Sonnet 5.5	$0.00099	$0.00099
Haiku 4.5	$0.00049	$0.00049

Measured 2mo ago against content hash ac65a0b33eae, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

financial-data 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 2mo 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 · 56 lines

How it starts

The opening of the file, as written. The whole thing — 56 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

This is a FastAPI-based financial data service that provides stock market information through RESTful APIs. The service uses Yahoo Finance (yfinance) as the primary data source to retrieve stock information, prices, news, financial statements, and other related data.

Code Architecture

Main Application: main.py - Contains all the API endpoints and FastAPI application setup
API Layer: src/api/ - Contains the business logic for fetching and processing financial data
Models: src/models/ - Pydantic models that define the structure of API responses
Common Utilities: src/common/ - Utility functions for caching, data conversion, and FastAPI response handling
Data Source: Uses Yahoo Finance (yfinance) library to fetch real-time financial data

Common Development Commands

Running the Application

source .venv/bin/activate
fastapi dev main.py

Dependencies

Dependencies are managed using uv (as indicated by pyproject.toml and uv.lock):

Python version: >=3.12
Main dependencies: fastapi, yfinance, financetoolkit, dotenv

API Structure

The API provides endpoints for:

Ticker information (/api/v1/ticker/info)
Stock prices (/api/v1/ticker/prices)
News (/api/v1/ticker/news)
Financial statements (income statement, balance sheet, cash flow)
Insider transactions and holdings
Financial metrics and calculations
Ticker lookup/search functionality

Key Components

Response Handling: All API responses follow a consistent format using BaseResponse model with code, data, and message fields
Data Conversion: Utilities to convert between camelCase and snake_case naming conventions
Caching: Built-in caching mechanism to improve performance and reduce API calls
Error Handling: Centralized exception handling for consistent error responses
Data Models: Comprehensive Pydantic models for all financial data types

Read the full file on GitHub · 56 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.

2mo ago First seen · 56 lines · 495 tokens per session scan A ac65a0b33eae

Subscribe to this mod's changes

financial-data CLAUDE.md is an instructions file published in the GitHub repository aostock/financial-data (2 stars, last pushed 1y ago), licensed Apache-2.0. It adds 495 tokens to every session, about $0.0020 per session on Opus 5.5. 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.

Backend and APIs Finance and fintech fastapi mcp-server yfinance

financial-data CLAUDE.md next to 6 instructions from other repositories
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financial-data: Instructions file for Claude Code