Glossary

A

A2A⁶ → Agent2Agent protocol. This site’s implementation answers documentation questions through search and read.
actor²⁰ → A running unit that processes events or performs work for a state machine. Declared Effect actors perform this repo’s side effects.
adapter¹⁹ → An implementation that connects an application-owned interface to a particular external technology or provider.
agent interfaces⁶ → The discovery documents and callable HTTP, MCP, A2A, and code-mode endpoints hosted by this site.
Alchemy → An infrastructure tool built with Effect. Its program declares cloud resources and can produce a plan before applying changes.
Alchemy Stack → One program that declares infrastructure and returns its outputs.

backpressure⁷ → A consumer’s demand limits how quickly its producer can progress. An unbounded queue can break that constraint.
binding²³ → A declared connection that gives a Cloudflare Worker a typed runtime value or access to a resource.

capability²¹ → One named action with a contract describing its accepted values and a server-side implementation that performs the work.
capability projection¹⁸ → Code that exposes a named action through a particular interface without adding separate business behavior.
cartridge³⁶ → A package for one job that includes its implementation and needed infrastructure. It must pass the project’s add-and-remove test.
cartridge test³⁶ → Add one package and one provision line, then remove them without breaking unrelated packages. The package owns its resources and connections.
client → Browser code that owns queries, named commands, and the local copy of server state.
code mode²¹ → Running one program that combines calls to declared actions inside a restricted environment.
composition root¹⁶ → Startup code that chooses and supplies the application’s service implementations.
ConfigProvider⁷ → The source of raw configuration inputs that Effect reads and validates.
configuration Layer⁷ → A description of how to build a service containing validated configuration values.
content-addressed output⁷ → Generated output identified by a hash of its content.
context⁹ → The collection of services supplied to running work in Effect.
contract²¹ → The shared name, input, output, failure, and metadata for an action. It contains no server-side implementation.

defect¹⁷ → An unexpected execution failure, separate from the failures that callers are expected to handle.

Effect¹⁷ → A TypeScript library for describing work with typed failures and required services. A runtime executes the description.
engine-neutral token⁷ → A segment of source text with a syntax role and font style, independent of Shiki’s types.
error accumulation⁹ → Collecting independent failures so one result reports all of them before generated files are written.
expected failure³⁶ → A declared failure carried in an Effect description’s E type parameter. Callers can handle it.

feature → A thin browser route and view that reads client state and calls named client commands.
fence³⁹ → Compiler checks, lint rules, and hooks that reject prohibited code and shortcuts. They do not prove every runtime behavior.
fence metadata¹⁴ → Options on the opening line of a Markdown code block. These options are separate from the project’s enforcement checks.
fiber⁷ → Independently running work in Effect. Its fork operation determines its lifetime and ownership.

handler²¹ → The server-side implementation called after input validation and any required approval.
highlighter port⁷ → An interface for turning source code into per-line syntax tokens.

idempotency⁷ → Repeating an operation creates no additional change beyond its first successful application.
interface²³ → A way to call a named action, such as the command line or HTTP API.
ISR⁵ → Incremental static regeneration: rebuilding a cached page after its revalidation interval while serving a previously generated page.

Layer¹³ → A description of how to build service implementations and supply what their construction needs.
Layer memoization¹³ → Sharing a constructed service within one build context by the identity of the Layer that builds it.

machine²⁰ → A definition of named states and the events that permit movement between them.
managed runtime⁸ → A runtime that retains constructed services between calls until it is disposed.
Markdown code fence¹⁴ → A code block delimited by backticks. Its opening line can carry a language and excerpt options.
MCP²⁷ → Model Context Protocol: a protocol through which an agent client discovers and calls tools.
memoization¹³ → Reusing a previously constructed result within a stated context. Service construction shares results by Layer identity within one build context.

no comments⁷ → Prose comments are banned. Explained tool directives, safety assertions, and type-only JavaScript JSDoc have stated exceptions.

observability⁷ → Understanding a running system through logs, metrics, and traces.

pin → An exact dependency version or source revision.
port¹⁹ → An application-owned interface named for the job the application needs.
projection¹⁸ → Code that turns a named action and its shared definition into a command, HTTP API, MCP tool, RPC interface, or code-mode interface.
provenance¹⁴ → The repository, commit, file, and original lines from which an excerpt comes.

read model → Derived data arranged for efficient reads. It does not become the authority for writes.
requirement¹⁷ → A service that a description of work still needs before it can run.
resource finalizer²⁰ → A cleanup operation registered with an owner or an acquire-use-release operation.
RPC → Remote procedure call: a client calls a named operation implemented on the server.
runtime boundary⁸ → The place where code outside Effect needs to execute a description of work.

Schema¹⁷ → A description of accepted values, their TypeScript types, and the rules for checking and converting them at runtime.
Scope²⁰ → An owner for registered cleanup operations. Closing it runs those operations.
scoped fiber⁷ → Independently running work owned by a cleanup scope. Closing that scope interrupts the work.
service¹⁶ → A named interface for one job. Callers request it by its identifier, and startup code supplies its implementation.
service tag¹⁶ → The identifier used to request a service, a named interface for one job, from Effect’s collection of available implementations.
source drift⁹ → A difference between selected pinned lines and the current source. It does not replace the pinned text.
state machine²⁰ → Named states and the events that permit movement between them.
stream backpressure⁷ → A stream consumer requests data as it can process it, limiting the producer’s progress.
surface²³ → In the motto “one capability, every surface”, a way to call a named action. Other prose uses “interface”.
system of record → The authoritative store for a fact. Derived copies can be rebuilt from it.

tautological tests²² → Tests whose expected answers repeat the implementation instead of stating an independent rule.
telemetry⁷ → The logs, measurements, and trace data recorded about a running system.
trace export⁷ → Sending recorded trace data to a collector. Sending, acceptance, and stored retrieval are separate observations.
trace span⁷ → A record of an operation’s timing and outcome.
tracing span⁷ → A record of an operation’s timing and outcome.
traversal concurrency⁷ → The number of collection items whose work can run at the same time.

Workers Cache⁵ → Cloudflare’s programmable cache for HTTP responses. Each location holds its own cached responses.