deepseek-harness/docs/cordis-catalog/events-and-services.md

Cordis Events & Services Catalog

An index reference to the wiring a plugin author works against: every cordis event you can listen to (exact signature + dispatch mode) and every ctx.<key> service you can call (exact public interface). It complements core-data-structures/, which catalogs the data structures these signatures move around — this page is the verbs, that page is the nouns.

This file is GENERATED from source (scripts/gen-cordis-catalog.ts) and verified fresh by pnpm run verify-cordis-catalog (part of doc-sync) — do not edit it by hand. Signature blocks use a ts cordis-catalog fence (skipped by doc-typecheck, since a bare signature is not standalone-compilable). Type names in a signature link to the page that documents them.

The harness tier below (the @deepseek-ai/dsh-* packages) is the vocabulary this repo owns. The inherited tier at the end is the cordis-core + loader/hmr/timer surface a plugin also sees — pinned vendor source, summarized tersely.

Events

Dispatch modes: emit (fire-and-forget), waterfall (each listener gets next() and may transform or veto — see waterfall semantics), parallel (awaited fan-out, no veto). The harness declares 22 events across 5 scopes.

agent/*

agent/created — emit

An agent was registered in the AgentRegistry and is ready to receive messages.

'agent/created'(agent: Agent): void

Types: Agent

Source: packages/core/agent/src/types.ts:136

agent/disposed — emit

An agent was disposed and removed from the registry; its fiber and any in-flight turn have been torn down.

'agent/disposed'(agent: Agent): void

Types: Agent

Source: packages/core/agent/src/types.ts:142

agent/error — emit

A step or turn errored. The loop reports a failure here (plus the logger) even when the error has no in-turn position for a session error event.

'agent/error'(agent: Agent, turn: number, step: number, error: Error): void

Types: Agent

Source: packages/core/agent/src/types.ts:219

agent/queued — emit

A message entered the agent's inbox (queued or steering). source is the resolved source (defaults applied), not the caller's raw options.

'agent/queued'(agent: Agent, content: ContentBlock[], info: { source: MessageSource; steering: boolean }): void

Types: Agent · ContentBlock · MessageSource

Source: packages/core/agent/src/types.ts:155

agent/request — waterfall

Waterfall: mutate the fully-assembled GenerateOptions before the model call (hooks, compaction, model switching, tool filtering, …). Call next() to delegate, or return without it to short-circuit.

'agent/request'(agent: Agent, turn: number, step: number, options: GenerateOptions, next: () => Promise<GenerateOptions>): Promise<GenerateOptions>

Types: Agent · GenerateOptions

Source: packages/core/agent/src/types.ts:188

agent/status — emit

Agent status changed (idle ⇄ running, or → disposed). Drive lifecycle off this transition, never off a status you just requested — send() does not flip status to running before it returns.

'agent/status'(agent: Agent, status: AgentStatus): void

Types: Agent

Source: packages/core/agent/src/types.ts:149

agent/steering — emit

Steering content was injected into a running turn.

'agent/steering'(agent: Agent, turn: number, content: ContentBlock[], source: MessageSource): void

Types: Agent · ContentBlock · MessageSource

Source: packages/core/agent/src/types.ts:213

agent/step-end — emit

A step ended.

'agent/step-end'(agent: Agent, turn: number, step: number): void

Types: Agent

Source: packages/core/agent/src/types.ts:179

agent/step-result — waterfall

Waterfall: post-process the assembled assistant Message before tool dispatch (validation, content rewriting, …).

'agent/step-result'(agent: Agent, turn: number, step: number, message: Message, next: () => Promise<Message>): Promise<Message>

Types: Agent · Message

Source: packages/core/agent/src/types.ts:194

agent/step-start — emit

A step (one model call plus its tool dispatch) began. step is 1-based within the turn; a turn runs one or more steps.

'agent/step-start'(agent: Agent, turn: number, step: number): void

Types: Agent

Source: packages/core/agent/src/types.ts:174

agent/stream-chunk — emit

A raw StreamChunk arrived from the model (token-level UI/log feed).

'agent/stream-chunk'(agent: Agent, turn: number, step: number, chunk: StreamChunk): void

Types: Agent · StreamChunk

Source: packages/core/agent/src/types.ts:208

agent/turn-continuation — waterfall

Waterfall: override the turn-continuation decision. The default (computed by the loop) is hadToolCalls || steeringInjected. Listeners can force-continue (/goal, /loop) or force-stop (budget guards).

'agent/turn-continuation'(agent: Agent, turn: number, defaultDecision: boolean, next: () => Promise<boolean>): Promise<boolean>

Types: Agent

Source: packages/core/agent/src/types.ts:201

agent/turn-end — emit

A turn ended. reason distinguishes a clean stop from a truncated or aborted one (completed | aborted | error | disposed | max-tokens).

'agent/turn-end'(agent: Agent, turn: number, reason: TurnEndReason): void

Types: Agent · TurnEndReason

Source: packages/core/agent/src/types.ts:168

agent/turn-start — emit

A turn began. turn is the 1-based turn number within the session.

'agent/turn-start'(agent: Agent, turn: number): void

Types: Agent

Source: packages/core/agent/src/types.ts:162

llm/*

llm/stream — waterfall

Waterfall around every streaming model call (retry, caching, routing). Bound to the LlmService; call next() to reach the resolved adapter's stream, or yield your own chunks to short-circuit.

'llm/stream'(this: LlmService, options: GenerateOptions, next: () => AsyncIterable<StreamChunk>): AsyncIterable<StreamChunk>

Types: GenerateOptions · StreamChunk

Source: packages/llm/llm/src/index.ts:31

session/*

session/created — emit

A session was created in the store.

'session/created'(session: Session): void

Source: packages/core/session/src/index.ts:30

session/event — emit

An event was appended to a session log (sync, fire-and-forget). This is the per-append feed a UI or invariant plugin tails.

'session/event'(session: Session, event: SessionEvent): void

Types: SessionEvent

Source: packages/core/session/src/index.ts:36

session/flush — parallel

Awaited durability checkpoint. The agent loop awaits ctx.parallel('session/flush', session) at every turn end; persistence plugins (JSONL, SQLite) drain their write-behind buffers here and on fiber dispose. Awaited (parallel), not a waterfall: every listener runs and the loop waits for all of them, but none can veto.

'session/flush'(session: Session): Promise<void> | void

Source: packages/core/session/src/index.ts:45

system-prompt/*

system-prompt/assemble — waterfall

Waterfall around prompt assembly — mutate or extend the PromptAssembly (sections + tool schemas) before it is rendered. Bound to the SystemPrompt service; call next() to delegate.

'system-prompt/assemble'(this: SystemPrompt, assembly: PromptAssembly, next: () => Promise<PromptAssembly>): Promise<PromptAssembly>

Source: packages/core/system-prompt/src/index.ts:24

system-prompt/change — emit

A section or tool provider was registered or unregistered (the assembly inputs changed).

'system-prompt/change'(): void

Source: packages/core/system-prompt/src/index.ts:30

tools/*

tools/change — emit

A tool was registered or unregistered (the available tool set changed).

'tools/change'(): void

Source: packages/core/tools/src/index.ts:48

tools/execute — waterfall

Waterfall around every tool execution — the single seam where sandbox, permission, hook, and plan-mode plugins wrap or veto a call. Listeners receive (exec, next): call next() to proceed (possibly around your own logic), or return a ToolExecutionResult without calling next() to short-circuit (veto).

'tools/execute'(this: ToolRegistry, exec: ToolExecution, next: () => Promise<ToolExecutionResult>): Promise<ToolExecutionResult>

Types: ToolExecution · ToolExecutionResult

Source: packages/core/tools/src/index.ts:43

Services

The 10 ctx.<key> services the harness provides. An abstract seam (e.g. ctx.bash) is implemented by a separate package; the interface is what consumers code against.

ctx.agentLoop — AgentLoop

The agent-loop plugin (ctx.agentLoop): creates ReactLoopAgents, runs their loops, and registers them in ctx.agents. Also implements the AgentFactory seam, so plugins create/resume agents through ctx.agents (the interface) without depending on this concrete package.

The loop itself is deliberately thin — every behavior beyond "call the model, run the tools, repeat" belongs to plugins listening on the event taxonomy declared in @deepseek-ai/dsh-agent.

create(id: AgentId, options: AgentOptions = {}): ReactLoopAgent
createAgent(options: CreateAgentOptions): AgentHandle
async resume(options: ResumeAgentOptions): Promise<AgentHandle>

Source: packages/core/agent-loop/src/index.ts:63

ctx.agents — AgentRegistry

Agent registry (ctx.agents): tracks live agents so UI, hook, and orchestrator plugins can find them without depending on the concrete loop package. Agent creation is provided by whichever plugin implements the AgentFactory (phase 1: @deepseek-ai/dsh-agent-loop), registered via setFactory.

setFactory(factory: AgentFactory): () => void
create(options: CreateAgentOptions): AgentHandle
async resume(options: ResumeAgentOptions): Promise<AgentHandle>
register(agent: Agent): () => void
get(id: AgentId): Agent | undefined
list(): Agent[]

Types: Agent

Source: packages/core/agent/src/index.ts:105

ctx.bash — BashExecutor (abstract seam)

Abstract bash execution service. Subclass, implement the abstract methods, and load the subclass as a plugin — it registers as ctx.bash (one implementation per context; loading a second throws, which is cordis' standard duplicate-service behavior).

Semantics every implementation must honor:

• run REJECTS only for infrastructure failures (unusable workdir, missing shell, pre-aborted signal). Nonzero exits, timeout kills, and abort kills RESOLVE with a descriptive BashRunResult — reporting a failed command is the tool layer's job, not an exception.
• start returns immediately; no timeout applies to background tasks (callers stop them via kill or the spec's AbortSignal). Completion must fire the onTaskDone listeners exactly once per task, and must NOT fire after the service is disposed.
• readOutput is incremental: consecutive reads never re-deliver output. Implementations bound their buffers; reads that lost data flag lossy and point at full-stream spill files when available.
• Disposal kills every running task and awaits their exit (no orphan processes survive fiber.dispose()).

abstract resolve(request: BashExecRequest): BashExecSpec
abstract run(spec: BashExecSpec): Promise<BashRunResult>
abstract start(spec: BashExecSpec): BashTask
abstract get(id: BashTaskId): BashTask | undefined
abstract ownerOf(id: BashTaskId): OwnerToken | undefined
abstract list(): BashTask[]
abstract readOutput(id: BashTaskId): BashTaskRead
abstract kill(id: BashTaskId): boolean
onTaskDone(listener: BashTaskListener): () => void

Types: BashExecRequest · BashExecSpec · BashRunResult · BashTask · BashTaskRead

Source: packages/bash/bash/src/index.ts:59

ctx.fileContext — FileContext

The file-context policy service. Injects fs, registers as ctx.fileContext, and is the only read/write/edit path the model-facing tools use.

owner(exec?: FileContextExec): object | undefined
async resolve(path: string): Promise<FsTarget>
async read(target: FsTarget, request: FileReadRequest, exec?: FileContextExec, signal?: AbortSignal): Promise<FileReadOutcome>
async write(target: FsTarget, content: string, exec?: FileContextExec, signal?: AbortSignal): Promise<FsWriteOutcome>
async edit(target: FsTarget, edit: FsEditRequest, exec?: FileContextExec, signal?: AbortSignal): Promise<FsEditOutcome>

Types: FsEditOutcome · FsEditRequest · FsTarget · FsWriteOutcome

Source: packages/fs/file-context/src/index.ts:65

ctx.fs — FileSystem (abstract seam)

Abstract filesystem provider service. Subclass, implement the six text-storage primitives, and load the subclass as a plugin — it registers as ctx.fs (one implementation per context; loading a second throws, cordis' standard duplicate-service behavior).

Semantics every backend must honor:

• resolve returns a stable FsTarget; the same underlying file reached by different input paths must yield the same targetKey so stale guards and target lookup agree across paths (e.g. through symlinks).
• stat returns FsInfo metadata (never content) or undefined when the target is absent.
• readText/streamText read the whole regular text file (the stream for large files); both own regular-file checks, UTF-8 decoding, binary/NUL rejection, and FS_NOT_TEXT.
• writeText is atomic temp-file + rename honoring the FsWriteExpectation.
• editText verifies expected.version BEFORE literal matching (so a stale edit reports FS_STALE_VERSION, not FS_EDIT_NOT_FOUND/ FS_AMBIGUOUS_EDIT against newer content), then applies literal replacement and writes atomically — all inside one mutation critical section.

abstract resolve(path: string): Promise<FsTarget>
abstract stat(target: FsTarget, signal?: AbortSignal): Promise<FsInfo | undefined>
abstract readText(target: FsTarget, signal?: AbortSignal): Promise<string>
abstract streamText(target: FsTarget, signal?: AbortSignal): Promise<AsyncIterable<string>>
abstract writeText(target: FsTarget, content: string, expected: FsWriteExpectation, signal?: AbortSignal): Promise<FsWriteOutcome>
abstract editText(target: FsTarget, edit: FsEditRequest, expected: { version: FsVersion }, signal?: AbortSignal): Promise<FsEditOutcome>

Types: FsEditOutcome · FsEditRequest · FsTarget · FsVersion · FsWriteOutcome

Source: packages/fs/fs/src/index.ts:90

ctx.llm — LlmService

The abstract llm service: an adapter registry plus a streaming model-call surface, interceptable via the llm/stream waterfall.

registerAdapter(models: string[], adapter: LlmAdapter): () => void
models(): string[]
stream(options: GenerateOptions): AsyncIterable<StreamChunk>

Types: GenerateOptions · StreamChunk

Source: packages/llm/llm/src/index.ts:69

ctx.sessionPersistence — SessionPersistence (abstract seam)

Abstract durable session-persistence service. Subclass, implement the abstract methods, and load the subclass as a plugin — it registers as ctx.sessionPersistence (one implementation per context; loading a second throws, cordis' standard duplicate-service behavior).

Contracts every implementation MUST honor (a DB backend asserts them inside a transaction; a file backend appends at EOF):

• Append-only; a crashed turn is closed, not truncated. Committed events — those at or below a flushed turn/end — are never rewritten. A crash can leave an unclosed final turn whose events are real (and possibly large); load preserves them and closes the orphaned turn with synthetic boundary events (see load). Only a never-fully-written torn tail fragment is discarded.
• Contiguous seq. A persisted log is contiguous: events[i].seq === i. load rejects a parse error or a seq gap in the COMMITTED region (unloadable); append's first event seq MUST equal the backend's stored next-seq (after load has balanced any interrupted turn).
• JSON-serializable data. SessionEventMap is merge-extensible and event.data is typed only as SessionEventMap[K], so append REJECTS non-JSON-serializable data with an error naming the offending event type. A backend snapshots (serializes/clones) each event when it buffers, since session.events hands out the live mutable object.
• Durability. append returns only once the batch is durable (the file backend fsyncs; a DB commits). create MAY defer the physical write until the first append (lazy materialization).

abstract create(meta: SessionHeader): Promise<void>
abstract append(id: SessionId, events: readonly SessionEvent[]): Promise<void>
abstract load(id: SessionId): Promise<{ meta: SessionHeader; events: SessionEvent[] }>
abstract list(): Promise<SessionHeader[]>

Types: SessionEvent

Source: packages/session-persistence/session-persistence/src/index.ts:98

ctx.sessions — SessionStore

In-memory session store (ctx.sessions).

Persistence is intentionally not implemented here — persistence plugins subscribe to session/event and flush on session/flush / dispose.

create(id?: SessionId, options?: CreateSessionOptions): Session
prepare(id?: SessionId, options?: CreateSessionOptions): Session
enter(session: Session): () => void
announce(session: Session): void
get(id: SessionId): Session | undefined
list(): Session[]

Source: packages/core/session/src/index.ts:229

ctx.systemPrompt — SystemPrompt

Registry service (ctx.systemPrompt): plugins contribute ordered text sections and tool-schema providers; the agent loop calls assemble() once per step.

section(section: PromptSection): () => void
tools(provider: () => ToolSchema[]): () => void
assemble(): Promise<PromptAssembly>

Source: packages/core/system-prompt/src/index.ts:71

ctx.tools — ToolRegistry

Tool registry (ctx.tools): tool plugins register definitions; the agent loop executes calls through the tools/execute waterfall. The registry contributes its schemas into the system-prompt assembly.

register(definition: ToolDefinition): () => void
get(name: string): ToolDefinition | undefined
schemas(): ToolSchema[]
async execute(exec: ToolExecution): Promise<ToolExecutionResult>

Types: ToolDefinition · ToolExecution · ToolExecutionResult

Source: packages/core/tools/src/index.ts:277

Inherited tier (cordis core + loader/hmr/timer)

The framework surface every plugin inherits, beyond the harness vocabulary above. This is pinned vendor source (vendoring policy); it is summarized here so the catalog is a complete picture of what ctx and the event bus offer, without elevating framework internals to the harness tier's prominence.

Inherited events

• internal/plugin — A plugin fiber was created. (vendor/cordis/src/events.ts:197)
• internal/status — A fiber changed lifecycle state. (vendor/cordis/src/events.ts:198)
• internal/service — Interception hook for a service binding (no core producer). (vendor/cordis/src/events.ts:199)
• internal/update — Waterfall: a fiber config update is being applied. (vendor/cordis/src/events.ts:200)
• internal/get — Waterfall: a service is being read from the store. (vendor/cordis/src/events.ts:201)
• internal/set — Waterfall: a service is being written to the store. (vendor/cordis/src/events.ts:202)
• internal/listener — A listener was registered. (vendor/cordis/src/events.ts:203)
• internal/dispatch — An event is being dispatched to listeners. (vendor/cordis/src/events.ts:204)
• hmr/change — A watched source file changed on disk. (vendor/hmr/src/index.ts:20)
• hmr/reload — Plugins are being reloaded after a change. (vendor/hmr/src/index.ts:21)
• exit — The process is exiting on a signal. (vendor/loader/src/index.ts:23)
• loader/config-update — The loader config tree changed. (vendor/loader/src/index.ts:24)
• loader/entry-init — A config entry is being initialized. (vendor/loader/src/index.ts:25)
• loader/partial-dispose — An entry is being partially disposed on reload. (vendor/loader/src/index.ts:26)
• loader/patch-context — A context is being patched during a reload. (vendor/loader/src/index.ts:27)

Inherited ctx members

• ctx.on / ctx.once — Register an event listener (disposable). (vendor/cordis/src/events.ts:29)
• ctx.emit / ctx.parallel / ctx.serial / ctx.bail / ctx.waterfall — Dispatch an event (sync / awaited / first-non-nullish / veto-chain). (vendor/cordis/src/events.ts:29)
• ctx.plugin / ctx.inject — Load a plugin / declare required services. (vendor/cordis/src/registry.ts:144)
• ctx.effect — Register a disposable side effect tied to the fiber. (vendor/cordis/src/fiber.ts:9)
• ctx.get / ctx.set / ctx.provide / ctx.accessor / ctx.mixin — Low-level service-store access and binding. (vendor/cordis/src/reflect.ts:7)
• ctx.extend / ctx.isolate / ctx.intercept — Derive a child context (scoped services / isolation / interception). (vendor/cordis/src/context.ts:35)
• ctx.root / ctx.scope / ctx.fiber / ctx.registry / ctx.reflect / ctx.events / ctx.logger — Ambient handles onto the running context graph. (vendor/cordis/src/context.ts:16)
• ctx.timer (+ interval / timeout / throttle / debounce / setTimeout / setInterval) — Disposable timer helpers. The timer key is provided at runtime; the six helpers are mixed onto ctx directly (declared via Pick). (vendor/timer/src/index.ts:4)
• ctx.loader — The config Loader that booted the app (present under the loader). (vendor/loader/src/index.ts:30)
• ctx.hmr — The hot-module-reload watcher (present under the hmr plugin). (vendor/hmr/src/index.ts:15)