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.
npx agentmods add instructions/ramm/fantastical-cli/agents-mdgit clone --depth 1 https://github.com/ramm/fantastical-cliWhat 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 | $0.03895 | $0.03895 |
| Opus 5 | $0.01947 | $0.01947 |
| Sonnet 5 | $0.00779 | $0.00779 |
| Haiku 4.5 | $0.00390 | $0.00390 |
Grade A, and why
fantastical-cli 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 yesterday.
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.
How it starts
The opening of the file, as written. The whole thing — 206 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md — Fantastical CLI + MCP Server
Project overview
A Python CLI tool (fantastical) providing composable access to Fantastical calendar data on macOS, with an MCP server for AI assistant integration. Installed via uv sync, run via uv run fantastical <command>.
Critical constraint: Fantastical does NOT sync to Calendar.app. Accounts added directly to Fantastical are invisible to Calendar.app and EventKit. All data access must go through Fantastical itself — JXA scripting or Apple Shortcuts with Fantastical's App Intents. Do NOT attempt EventKit, CalendarStore, or Calendar.app bridges.
Architecture
src/fantastical/
├── backend/
│ ├── jxa.py # osascript -l JavaScript subprocess runner
│ ├── fantastical.py # JXA scripts (calendars) + URL scheme (create)
│ ├── shortcuts.py # `shortcuts run` CLI wrapper (event queries, attendees, setup checks)
│ └── shortcut_gen.py # Programmatic .shortcut file generation + signing
├── api.py # Business logic — both CLI and MCP call this
├── cli.py # Click CLI — user-facing, formats output
└── server.py # FastMCP server — compact output, event/attendee caching
Layer rules
backend/touches macOS. Raw subprocess calls, JXA scripts, URL schemes. Returns parsed Python dicts. Never imported by server.py or cli.py directly — only through api.py.api.pyis the single source of truth. Combines backends, resolves dates ("today" -> ISO), handles "shortcuts not configured" gracefully. Returns clean dicts.cli.pycalls onlyapi.py. Formats for humans (tables) or machines (--json). Never calls backends directly.server.pycalls onlyapi.py. Returns compact tab-separated text for list/search tools (with in-memory event/attendee caching), JSON for create. Seeserver.pyfor per-tool response formats.
When adding a new capability: add backend function -> add api.py function -> add CLI command + MCP tool.
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.
- yesterday First seen · 206 lines · 3,895 tokens per session scan A 8795087b7f69
fantastical-cli AGENTS.md is an instructions file published in the GitHub repository ramm/fantastical-cli (4 stars, last pushed 6mo ago), licensed MIT. It adds 3,895 tokens to every session, about $0.0195 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.
Other instructions, from other repositories
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
buildNext
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
Instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
spec-kit AGENTS.md
Instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
langchain AGENTS.md
Instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.