# Urbit OS

- [What is Urbit OS?](https://docs.urbit.org/urbit-os/what-is-urbit-os.md): Introduction to Urbit OS, a functional, deterministic personal server operating system. Includes documentation for the Arvo kernel, its modules, and the standard distribution in the %base desk.
- [Base](https://docs.urbit.org/urbit-os/base.md): Documentation for the %base desk, the Urbit OS standard distribution containing the kernel, Arvo, Hoon standard library, system apps like %hood, and affordances for writing threads.
- [Hood](https://docs.urbit.org/urbit-os/base/hood.md): API reference for %hood, a Gall agent that interfaces with Urbit OS. Includes documentation for its modules Drum (CLI management), Helm (system control), and Kiln (desk updates and filesystem).
- [Threads](https://docs.urbit.org/urbit-os/base/threads.md): Guide to writing threads, transient monadic functions for complex IO operations, managed by the %spider agent or the Khan vane, with tutorials, examples, and API reference.
- [Basics Tutorial](https://docs.urbit.org/urbit-os/base/threads/basics.md): Tutorial covering thread fundamentals including strands, monadic composition with form and pure, bind operations, input/output handling, and practical examples for writing threads.
- [Bind](https://docs.urbit.org/urbit-os/base/threads/basics/bind.md): Guide to monadic bind operations for strand composition using the ;< micgal rune, chaining strands sequentially, error handling, and strandio library functions for complex thread operations.
- [Fundamentals](https://docs.urbit.org/urbit-os/base/threads/basics/fundamentals.md): Thread fundamentals. Transient agent functionality, strand composition, thread definition, the +form and +pure arms, threads' location in /ted directory, and creating basic threads.
- [Input](https://docs.urbit.org/urbit-os/base/threads/basics/input.md): Guide to strand input including $bowl structure with ship, timing, and subscription data, input types (pokes, signs, agent communication), and accessing input data within thread execution.
- [Output](https://docs.urbit.org/urbit-os/base/threads/basics/output.md): Guide to strand output including cards and response codes (%wait, %skip, %cont, %fail, %done), flow control mechanisms, error handling, and completion patterns in thread execution.
- [Summary](https://docs.urbit.org/urbit-os/base/threads/basics/summary.md): Summary and recap of thread concepts including %spider agent management, strand composition, +form/+pure/+bind operations, input/output patterns, and strandio utility functions.
- [HTTP API Guide](https://docs.urbit.org/urbit-os/base/threads/http-api.md): Guide to running threads via HTTP API - URL structure, mark conversion, JSON handling, and authenticated requests through Eyre.
- [Spider API Reference](https://docs.urbit.org/urbit-os/base/threads/api.md): Spider API reference for starting, stopping, and interacting with threads. Pokes, subscriptions, and thread lifecycle management.
- [Strandio Reference](https://docs.urbit.org/urbit-os/base/threads/strandio.md): Reference for Strandio library functions - HTTP requests, pokes, subscriptions, scries, timers, and more for thread programming.
- [Examples](https://docs.urbit.org/urbit-os/base/threads/examples.md): Collection of practical thread examples including Gall agent integration, JSON fetching, child thread management, main-loop patterns, agent communication, scrying, and fact handling.
- [Child Thread](https://docs.urbit.org/urbit-os/base/threads/examples/child-thread.md): Thread examples showing how parent threads can start/stop child threads, and get their results.
- [Fetch JSON](https://docs.urbit.org/urbit-os/base/threads/examples/get-json.md): Practical example of fetching and parsing JSON data in threads using strandio's +fetch-json function, demonstrated with a Bitcoin price fetcher that queries external APIs and processes responses.
- [Gall](https://docs.urbit.org/urbit-os/base/threads/examples/gall.md): Examples of Gall agent integration with threads covering thread lifecycle management, starting threads, handling results, subscription patterns, cancellation, and inter-thread communication.
- [Poke Thread](https://docs.urbit.org/urbit-os/base/threads/examples/gall/poke-thread.md): Gall agent example demonstrating how to poke running threads.
- [Start Thread](https://docs.urbit.org/urbit-os/base/threads/examples/gall/start-thread.md): Gall agent examples for starting threads - inline vs file threads, Khan vs Spider APIs, thread IDs and subscription patterns.
- [Stop Thread](https://docs.urbit.org/urbit-os/base/threads/examples/gall/stop-thread.md): Gall agent example demonstrating how to stop running threads - Spider-stop pokes and thread lifecycle management.
- [Take Facts](https://docs.urbit.org/urbit-os/base/threads/examples/gall/take-facts.md): Gall agent example for receiving facts from running threads - subscription patterns and fact handling while threads execute.
- [Take Result](https://docs.urbit.org/urbit-os/base/threads/examples/gall/take-result.md): Gall agent examples showing how to handle thread results - success/failure cases for Khan and Spider thread execution.
- [Main-loop](https://docs.urbit.org/urbit-os/base/threads/examples/main-loop.md): Advanced thread examples using main-loop for continuous processing, multiple function patterns, and subscription handling.
- [Poke Agent](https://docs.urbit.org/urbit-os/base/threads/examples/poke-agent.md): Example thread demonstrating how to poke agents - sending a |hi command to a ship via the hood agent.
- [Scry](https://docs.urbit.org/urbit-os/base/threads/examples/scry.md): Thread example showing how to scry ames for ship IP addresses and ports - practical scrying with formatted output.
- [Take Fact](https://docs.urbit.org/urbit-os/base/threads/examples/take-fact.md): Thread example demonstrating subscription and fact handling - watching agents, taking facts, and processing subscription data.
- [Kernel](https://docs.urbit.org/urbit-os/kernel.md): API documentation and guides for the Urbit OS kernel and its modules Ames, Behn, Clay, Dill, Eyre, Gall, Iris, Jael, Khan, and Lick.
- [Arvo](https://docs.urbit.org/urbit-os/kernel/arvo.md): High-level technical introduction to Arvo, Urbit's functional operating system. Covers event handling, deterministic execution, and ACID database properties.
- [Cryptography](https://docs.urbit.org/urbit-os/kernel/arvo/cryptography.md): Arvo cryptography overview - Azimuth keys, networking keys, and cryptographic components across the system.
- [Move Trace](https://docs.urbit.org/urbit-os/kernel/arvo/move-trace.md): Arvo move trace tutorial - debugging kernel operations, tracing moves, and understanding system message flow.
- [Scries](https://docs.urbit.org/urbit-os/kernel/arvo/scry.md): Arvo scry guide - read-only requests to the global namespace, endpoint mechanics, and data retrieval patterns.
- [Subscriptions](https://docs.urbit.org/urbit-os/kernel/arvo/subscriptions.md): Arvo subscriptions guide - reactive data flow, subscription types, Clay/Gall/Jael subscriptions, and stream mechanics.
- [Ames](https://docs.urbit.org/urbit-os/kernel/ames.md): Technical documentation for Ames, Urbit's encrypted peer-to-peer networking protocol and the Arvo vane that implements it. Includes packet format, flows, congestion control, and cryptography.
- [Ames API Reference](https://docs.urbit.org/urbit-os/kernel/ames/tasks.md): Ames API reference - networking tasks for messaging, packet handling, remote scries, and ship communication.
- [Ames Cryptography](https://docs.urbit.org/urbit-os/kernel/ames/cryptography.md): Ames cryptography reference - AES encryption, Curve25519 key exchange, packet signing, and comet self-attestation.
- [Ames Data Types](https://docs.urbit.org/urbit-os/kernel/ames/data-types.md): Ames data type reference - networking structures for packets, lanes, ships, addresses, and message flow state.
- [Ames Scry Reference](https://docs.urbit.org/urbit-os/kernel/ames/scry.md): Ames scry reference - network queries for peers, routes, message flows, bones, and ship connectivity information.
- [Behn](https://docs.urbit.org/urbit-os/kernel/behn.md): Documentation for Behn, Arvo's timer module for scheduling and managing timers.
- [Behn API Reference](https://docs.urbit.org/urbit-os/kernel/behn/tasks.md): Behn API reference - timer tasks for setting and cancelling timers, scheduling events, and time management.
- [Behn Examples](https://docs.urbit.org/urbit-os/kernel/behn/examples.md): Behn timer examples - setting timers with wait tasks, handling wake gifts, and timing operations.
- [Behn Scry Reference](https://docs.urbit.org/urbit-os/kernel/behn/scry.md): Behn scry reference - timer queries for debugging timers, next timer, and scheduled timer information.
- [Clay](https://docs.urbit.org/urbit-os/kernel/clay.md): Documentation for Clay, Arvo's version-controlled, referentially-transparent, and global filesystem, including architecture, data types, marks, and usage patterns.
- [Clay API Reference](https://docs.urbit.org/urbit-os/kernel/clay/tasks.md): Clay API reference - filesystem tasks for reading, writing, tracking changes, and managing desks.
- [Clay Architecture](https://docs.urbit.org/urbit-os/kernel/clay/architecture.md): Clay filesystem architecture - distributed revision control, typed data, persistence, and versioned filesystem design.
- [Clay Data Types](https://docs.urbit.org/urbit-os/kernel/clay/data-types.md): Clay data type reference - filesystem structures for files, desks, revisions, merges, and version control.
- [Clay Examples](https://docs.urbit.org/urbit-os/kernel/clay/examples.md): Clay filesystem examples - reading files, tracking changes, managing desks, merging, and filesystem operations.
- [Clay Scry Reference](https://docs.urbit.org/urbit-os/kernel/clay/scry.md): Clay scry reference - filesystem queries by care for reading files, directories, hashes, and metadata.
- [Filesystem Hierarchy](https://docs.urbit.org/urbit-os/kernel/clay/filesystem.md): Clay filesystem hierarchy - desk organization, folder structure, app/gen/lib/sur/sys directories and conventions.
- [Marks](https://docs.urbit.org/urbit-os/kernel/clay/marks.md): Guide to using marks, Clay's conversion functions.
- [Mark Examples](https://docs.urbit.org/urbit-os/kernel/clay/marks/examples.md): Clay mark examples - CSV mark implementation with parsing, validation, and conversion code samples.
- [Using Marks](https://docs.urbit.org/urbit-os/kernel/clay/marks/using-marks.md): Clay marks usage - using mark cores and conversion gates for data transformation and type-safe operations.
- [Writing Marks](https://docs.urbit.org/urbit-os/kernel/clay/marks/writing-marks.md): Clay marks guide - writing mark files for data type conversion, validation, parsing, and format handling.
- [Using Clay](https://docs.urbit.org/urbit-os/kernel/clay/using.md): Clay usage guide - reading, subscribing, Unix sync, merge strategies, and filesystem best practices.
- [Dill](https://docs.urbit.org/urbit-os/kernel/dill.md): Guide to Dill, Arvo's terminal driver vane.
- [Dill API Reference](https://docs.urbit.org/urbit-os/kernel/dill/tasks.md): Dill API reference - terminal tasks for session management, input/output, and system printing.
- [Dill Data Types](https://docs.urbit.org/urbit-os/kernel/dill/data-types.md): Dill data type reference - terminal structures for dimensions, sessions, input, and output handling.
- [Dill Scry Reference](https://docs.urbit.org/urbit-os/kernel/dill/scry.md): Dill scry reference - terminal queries for sessions and system state information.
- [Eyre](https://docs.urbit.org/urbit-os/kernel/eyre.md): Guide to Eyre, Arvo's HTTP server vane.
- [EAuth](https://docs.urbit.org/urbit-os/kernel/eyre/eauth.md): Eyre authentication guide - web login, session management, cookies, and secure authentication mechanisms.
- [Eyre Data Types](https://docs.urbit.org/urbit-os/kernel/eyre/data-types.md): Eyre data type reference - web server structures for HTTP requests, responses, sessions, and server state.
- [Eyre External API](https://docs.urbit.org/urbit-os/kernel/eyre/external-api-ref.md): Eyre external API reference - HTTP endpoints, channel communication, authentication, and web interface integration.
- [Eyre Internal API](https://docs.urbit.org/urbit-os/kernel/eyre/tasks.md): Eyre API reference - web server tasks for HTTP handling, binding URLs, serving content, and session management.
- [Eyre Scry Reference](https://docs.urbit.org/urbit-os/kernel/eyre/scry.md): Eyre scry reference - web server queries for connections, bindings, authentication, and HTTP server state.
- [Low-Level Eyre Guide](https://docs.urbit.org/urbit-os/kernel/eyre/guide.md): Eyre web server guide - HTTP request handling, URL binding, authentication, channels, and web application development.
- [Noun channels](https://docs.urbit.org/urbit-os/kernel/eyre/noun-channels.md): Eyre noun channels guide - direct noun communication over HTTP for efficient data exchange with applications.
- [Gall](https://docs.urbit.org/urbit-os/kernel/gall.md): Documentation for Gall, Arvo's application framework for Urbit userspace apps.
- [Gall API Reference](https://docs.urbit.org/urbit-os/kernel/gall/gall-api.md): Gall API reference - agent notes and cards for communication, requests, arvo tasks, and inter-agent messaging.
- [Gall Data Types](https://docs.urbit.org/urbit-os/kernel/gall/data-types.md): Gall data type reference - agent structures for subscriptions, bowls, cards, signs, and agent lifecycle management.
- [Gall Scry Reference](https://docs.urbit.org/urbit-os/kernel/gall/scry.md): Gall scry reference - agent queries and vane-level endpoints for agent state, subscriptions, and metadata.
- [Iris](https://docs.urbit.org/urbit-os/kernel/iris.md): Documentation for Iris, Arvo's HTTP client module for making HTTP requests.
- [Iris API Reference](https://docs.urbit.org/urbit-os/kernel/iris/tasks.md): Iris API reference - HTTP client tasks for making requests, canceling requests, and receiving HTTP responses.
- [Iris Data Types](https://docs.urbit.org/urbit-os/kernel/iris/data-types.md): Iris data type reference - HTTP client structures for responses, MIME data, and outbound request configuration.
- [Iris Example](https://docs.urbit.org/urbit-os/kernel/iris/example.md): Iris HTTP client example - fetching remote resources with GET requests, handling responses, and processing HTTP data.
- [Jael](https://docs.urbit.org/urbit-os/kernel/jael.md): Guide to Jael, Arvo's vane for networking key infrastructure.
- [Jael API Reference](https://docs.urbit.org/urbit-os/kernel/jael/tasks.md): Jael API reference - PKI tasks and gifts for key management, subscriptions, domains, and ship identity operations.
- [Jael Data Types](https://docs.urbit.org/urbit-os/kernel/jael/data-types.md): Jael data type reference - PKI structures for keys, points, diffs, blocks, seeds, and Azimuth ship identity data.
- [Jael Examples](https://docs.urbit.org/urbit-os/kernel/jael/examples.md): Practical examples of Jael PKI tasks - subscribing to key updates, managing domains, web login codes, and key subscriptions.
- [Jael Scry Reference](https://docs.urbit.org/urbit-os/kernel/jael/scry.md): Jael scry reference - PKI queries for keys, lifes, rifts, domains, subscriptions, and ship identity information.
- [Khan](https://docs.urbit.org/urbit-os/kernel/khan.md): Guide to Khan, Arvo's thread-runner vane.
- [Khan API Reference](https://docs.urbit.org/urbit-os/kernel/khan/tasks.md): Khan API reference - thread runner tasks for executing threads, handling results, and thread lifecycle management.
- [Khan Data Types](https://docs.urbit.org/urbit-os/kernel/khan/types.md): Khan data type reference - thread runner structures for results, errors, and thread execution state.
- [Khan Example](https://docs.urbit.org/urbit-os/kernel/khan/example.md): Khan thread runner example - running threads from Gall agents with success/failure handling and result processing.
- [Lick](https://docs.urbit.org/urbit-os/kernel/lick.md): Guide to Lick, Arvo's IPC vane.
- [Lick API Reference](https://docs.urbit.org/urbit-os/kernel/lick/tasks.md): Lick API reference - IPC tasks for socket creation, data transmission, and inter-process communication.
- [Lick Guide](https://docs.urbit.org/urbit-os/kernel/lick/guide.md): Lick IPC guide - building applications that communicate with external programs through Unix sockets.
- [Lick Examples](https://docs.urbit.org/urbit-os/kernel/lick/examples.md): Lick IPC examples - inter-process communication with external programs, socket management, and data exchange.
- [Lick Scry Reference](https://docs.urbit.org/urbit-os/kernel/lick/scry.md): Lick scry reference - IPC queries for debugging socket connections and port status.


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