agentmods.dev

frankfurter: Instructions file for Codex

AGENTS.md

frankfurter AGENTS.md is an instructions file for Codex, OpenCode from lineofflight/frankfurter. It costs 1,434 tokens per session, scanned A, original, MIT.

A project guide for Frankfurter, an open-source Ruby API that provides reference currency exchange rates. It describes the repository structure, collaboration rules, and the requirement to work in a separate Git worktree.

In plain words
What is it for?
Use it when preparing a development worktree, learning the repository architecture, and following its collaboration and coding conventions.
Why use it?
It helps coding agents avoid interfering with other contributors and understand the project before making changes.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md.

This is lineofflight/frankfurter's own configuration. It tells Codex and OpenCode how to work on frankfurter 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 frankfurter configures →

not rated 2.1krepo +18 changed 1mo ago A scan 1,434 tokens original MIT
View source ↗ lineofflight/frankfurter frankfurter.dev
About the project

Frankfurter is an open-source API that provides daily currency exchange rates collected from institutional sources. Developers use it to retrieve currency data, convert amounts, or run their own instance with Docker. The catalogue entries are add-ons for working with the API.

lineofflight/frankfurter · 2,069 stars · on GitHub · frankfurter.dev

Reuse

Borrowing it

Nothing to install: this file belongs to lineofflight/frankfurter. 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/lineofflight/frankfurter/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/lineofflight/frankfurter

Made for: Codex, OpenCode.

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 frankfurter AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/lineofflight/frankfurter/agents-md/github.svg)](https://agentmods.dev/instructions/lineofflight/frankfurter/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/lineofflight/frankfurter/agents-md"><img src="https://agentmods.dev/badge/instructions/lineofflight/frankfurter/agents-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.

agentmods 80×15 button for frankfurter AGENTS.md

Your own site · 80×15
<a href="https://agentmods.dev/instructions/lineofflight/frankfurter/agents-md"><img src="https://agentmods.dev/badge/instructions/lineofflight/frankfurter/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 1,434 This file is loaded in full into every session.
When invoked 1,434 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 $0.01434 $0.01434
Opus 5.5 $0.00574 $0.00574
Sonnet 5.5 $0.00287 $0.00287
Haiku 4.5 $0.00143 $0.00143

Measured 1mo ago against content hash f8c5d00431d4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

frankfurter AGENTS.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 1mo 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.

AGENTS.md · 79 lines

How it starts

The opening of the file, as written. The whole thing — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Frankfurter

Frankfurter is a currency data API tracking reference exchange rates from institutional sources. Built with Roda, SQLite (via Sequel), Puma, Rufus scheduler, and Cloudflare.

Commands

# Test and lint
APP_ENV=test bundle exec rake         # Lint and test suite
APP_ENV=test bundle exec rake rubocop # Linter only
APP_ENV=test bundle exec rake spec    # Test suite only (rerun once if SQLite3::BusyException occurs)

# Database & Blends
bundle exec rake db:setup             # Migrations + seed providers
bundle exec rake backfill             # Backfill all providers (or backfill[key])
bundle exec rake blend:rebuild        # Full rebuild of materialized blend tables
bundle exec rake blend:parity         # Verify table vs live blend query parity
bundle exec rake rollups:rebuild      # Rebuild weekly and monthly rollups

# Local server
bundle exec puma -C config/puma.rb    # Web server on :8080
bundle exec foreman start             # Web + scheduler (mirrors prod)

Separate SQLite databases per environment (APP_ENV). Minitest suite with VCR/WebMock and transactional rollback.

Architecture & Blending

  • Pipeline: Native provider rates, less one-day spikes (RateSpike), rebase to USD pivot (BaseConversion), outlier-screened (Consensus), recency-decay weighted (WeightedAverage), and peg-anchored (PegAnchor).
  • Materialized Blends: Sparse tables (blended_rates, blended_weekly_rates, blended_monthly_rates) store precomputed USD blends. Plain V2 queries hit these tables directly; missing buckets or filtered queries fall back to live computation.
  • APIs: Legacy V1 (ECB-only) and V2 (multi-provider/blended) mounted in lib/app.rb. OpenAPI specs at lib/public/v1/openapi.json and lib/public/v2/openapi.json.
  • Provider Ingestion: Scheduled in bin/schedule via cron expressions in db/seeds/providers/*.json. Adapters (lib/provider/adapters/) handle pure fetch and parse. Use midpoint(buy, sell) for bid/ask sources to avoid float noise.
  • Currency Patches: Historical currencies and name overrides are configured in db/seeds/currency_patches.json and loaded via lib/currency_patches.rb.

Read the full file on GitHub · 79 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. 1mo ago Changed · -7 lines · +152 tokens per session f8c5d00431d4
  2. 1mo ago Changed · +10 lines · +347 tokens per session ef155290a966
  3. 1mo ago Changed · -342 lines · -4,432 tokens per session 243c08c7ef0e
  4. 1mo ago Changed · +51 lines · +598 tokens per session 6dc93f74c4dd
  5. 1mo ago Changed · +23 lines · +254 tokens per session 29bc3e669f92
  6. 1mo ago Changed · -4 lines · -60 tokens per session b578dca0b069
  7. 1mo ago Changed · +14 lines · +183 tokens per session 6a7cc50147e9
  8. 2mo ago First seen · 334 lines · 4,392 tokens per session scan A fa3526e8e40a

Subscribe to this mod's changes

frankfurter AGENTS.md is an instructions file published in the GitHub repository lineofflight/frankfurter (2,069 stars, last pushed 2d ago), licensed MIT. It adds 1,434 tokens to every session, about $0.0057 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 2026-08-30.

Rubyapicurrencycurrency-apicurrency-convertermoney
Related

frankfurter AGENTS.md compared with instructions from other repositories

frankfurter AGENTS.md next to 6 instructions from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
frankfurter AGENTS.mdlineofflight/frankfurterInstructions file2.1k2d agoMITA1,434Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA9,719GitHub Copilot
next.js AGENTS.mdvercel/next.jsInstructions file143kyesterdayMITA7,461Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchainInstructions file149kyesterdayMITA4,680Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA5,516GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscodeInstructions file195kyesterdayMITA3,093GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harnessInstructions file274k2d agoMITA4,313Codex, OpenCode