Optional modelModel identifier. Accepted in two formats:
"gpt-4o") when provider is also set. Preferred."provider:model" combined string (e.g. "openai:gpt-4o").Optional providerProvider name (e.g. "openai", "anthropic", "ollama").
Auto-detected from environment API keys when omitted.
Optional instructionsFree-form system instructions prepended to the system prompt.
Optional nameDisplay name for the agent, injected into the system prompt.
Optional apiOverride the provider API key instead of reading from environment variables.
Optional baseOverride the provider base URL (useful for local proxies or Ollama). An empty or whitespace-only value is
unset: a same-provider setDefaultProvider() URL, then the provider's URL variable, apply as with none. A seat
of an agency with a blank value takes the agency-level baseUrl as a seat with none does.
Optional personalityHEXACO-inspired personality trait overrides (0–1 scale).
Encoded as a human-readable trait string appended to the system prompt.
The SOUL.md spellings honestyHumility / honesty_humility and
opennessToExperience are accepted for honesty and openness; when
both spellings are given, the canonical key wins.
Optional toolsTools available to the agent on every call.
Accepts:
ExternalToolRegistry (Record, Map, or iterable)ToolDefinitionForLLM[]Optional maxMaximum number of agentic steps (LLM calls) per invocation. Defaults to 5.
Optional maxUpper bound on completion tokens for each LLM call the agent makes.
Forwarded to the underlying generateText / streamText call on
every generate(), stream(), and session.send() invocation.
Caps tail spend when a model misbehaves and yaps past the intended output size. Omit to use the provider default — AnthropicProvider defaults to 16000 (set 2026-05-17; was 4096), OpenAIProvider defaults to 4096, GeminiProvider defaults to 8192. Set to ~2× the agent's typical response size so normal calls finish naturally and only runaway generations hit the cap.
// Cap a roleplay agent at 1024 — short turns, fast feedback.
const companion = agent({
provider: 'anthropic',
model: 'claude-sonnet-4-6',
instructions: 'Reply in character. 2-3 sentences.',
maxTokens: 1024,
});
// Tool-use agent emitting verbose JSON — go big so structured
// output doesn't truncate mid-token. Opus 4.7 supports 32000.
const codegen = agent({
provider: 'anthropic',
model: 'claude-opus-4-7',
tools: { GenerateCode, RunTests, JudgeOutput },
maxTokens: 16000,
});
Optional thinkingExtended-thinking switch forwarded to Claude models on every
generate() / stream() / session call this agent makes. Any positive
budgetTokens turns adaptive thinking on (the number itself is not
sent). false turns thinking off with the model's own off shape; Opus
5.5, Fable and Mythos always think. Omitted keeps the model's default:
thinking on for Opus 5 and later, Sonnet 5 and later, Fable and Mythos,
off for older models. Other providers ignore it.
const codegen = agent({
provider: 'anthropic',
model: 'claude-opus-5',
tools: { GenerateCode, RunTests, JudgeOutput },
maxTokens: 24000,
thinking: { budgetTokens: 8000 },
});
Optional effortReasoning-effort control forwarded to every generate/stream/session call.
On effort-capable Claude models (Opus 4.5+, Sonnet 4.6, Fable/Mythos 5) the
provider sends output_config.effort (low|medium|high|xhigh|max). On
OpenAI reasoning models (o-series, GPT-5.x) the provider sends
reasoning_effort (chat) / reasoning.effort (Responses), with max
clamping to xhigh — OpenAI's ceiling — and a model-aware guard capping
xhigh → high on ids not probe-verified for xhigh (gpt-5.5/5.6 families
are verified). Independent of thinking; ignored on unsupported
models/values. Works per-agent in agency() rosters — each sub-agent may
pin its own depth.
Optional customProvider-specific TOP-LEVEL request-payload parameters forwarded verbatim
on every generate/stream/session call via
ModelCompletionOptions.customModelParams. Providers spread these onto
the outgoing request body — the escape hatch for params the typed options
don't model, e.g. OpenRouter provider-routing preferences:
customModelParams: { provider: { sort: 'throughput' } }
Optional memoryMemory configuration. agent() reads it only with runtime: 'gmi', where true
or a MemoryConfig turns on cognitive memory for the agent's sessions (its
embedding and consolidation fields are read) and false keeps it off, also
under cognition: 'full'. A session's message history is set by history, not
by this field.
Optional ragRetrieval-Augmented Generation configuration.
Optional discoveryRuntime capability discovery configuration.
Optional guardrailsGuardrail policy identifiers or structured config. agency() evaluates
none of them (see GuardrailsConfig), and agent() does not apply
them.
string[] — shorthand; agency() reads it as the output list.GuardrailsConfig — separate input and output lists.Optional securitySecurity tier. Accepted and not enforced (see SecurityTier).
Optional permissionsTool and resource permission fields. Accepted and not enforced (see PermissionsConfig).
Optional hitlHuman-in-the-loop approval configuration.
Optional emergentEmergent agent synthesis configuration.
Optional voiceVoice interface configuration.
Optional avatarAvatar visual presentation configuration.
Optional channelsChannel adapter configurations keyed by channel name. Values are channel-specific option objects passed through opaquely.
Optional outputOutput schema for structured generation.
Accepts a Zod schema at runtime; typed as unknown here to avoid a
hard dependency on the zod package in the types layer.
Optional provenanceProvenance and audit-trail configuration.
Optional observabilityObservability and telemetry configuration.
Optional onEvent callbacks fired at various lifecycle points during the run. agency() fires them for its run. A gmi() agent
fires them only for the teams it launches with launch_agency (agencies.launch), each named
launch:<agencyId>, and for those launches' failures; its own turns fire none, and neither does agent() without
runtime: 'gmi'.
Optional controlsResource limits (tokens, cost, time). agency() and the full runtime
enforce every field against the entire run. The lightweight agent()
helper forwards two of them per call: maxTotalTokens caps each LLM
call's completion output (mapped to maxTokens when no explicit
maxTokens is set, NOT the prompt+completion run total) and
maxDurationMs bounds each LLM request (mapped to requestTimeout).
The remaining fields stay agency()-only.
Optional dependsNames of other agents in the agency that must complete before this agent runs.
Used with strategy: 'graph' to build an explicit dependency DAG.
Agents with no dependsOn, or an empty one, are roots and run first. agency() throws
AgencyConfigError, naming the agent, for a value that is not an array of names.
`dependsOn: ['researcher']` — this agent waits for `researcher` to finish.
Optional cognitiveCognitive mechanisms config: the eight memory mechanisms of
CognitiveMemoryManager (reconsolidation, retrieval-induced forgetting,
involuntary recall, feeling of knowing, temporal gist, schema encoding,
source-confidence decay and emotion regulation). Pass {} for the
defaults, or override fields per mechanism.
The mechanisms run inside a CognitiveMemoryManager initialized with this
config (CognitiveMemoryConfig.cognitiveMechanisms). agent() without
runtime: 'gmi' and agency() construct no memory manager, so they log a
warning and leave this field unused; agent({ runtime: 'gmi' }) with memory
on passes it to the agent's memory manager. On the full runtime, a
gmiManagerConfig.cognitiveMemoryFactory builds the manager for each GMI.
Optional verifyVerify citations after generate() and default-runtime session calls.
When set, generate() produces the answer, then fetches sources for the
user's input with the configured retriever and scores each atomic claim
of the answer against them via CitationVerifier. The resulting
VerifiedResponse is attached to the result's grounding field — no
separate verifier.verify(text, sources) call needed. On the default
runtime, session.send() also checks its reply and session.stream()
exposes a grounding promise that runs after its text completes.
Direct stream() and GMI session calls do not verify.
When the retriever returns no sources,
or retrieval or the verifier fails, grounding stays unset and the
answer is returned as generated.
Pass a config object with the embedding function and the source retriever the verifier should use:
const docsAgent = agent({
provider: 'openai',
model: 'gpt-4o',
verifyCitations: {
embedFn: async (texts) => (await embeddingManager.generateEmbeddings({ texts })).embeddings,
retrieve: (query) => retriever.search(query),
},
});
const result = await docsAgent.generate('How do I configure a guardrail?');
console.log(result.text);
console.log(result.grounding?.overallGrounded);
for (const claim of result.grounding?.claims ?? []) {
if (claim.verdict !== 'supported') console.warn(claim.text);
}
Optional runtimeWhich engine serves the seat. 'legacy' (the default) calls the model through
generateText and streamText; 'gmi' serves each of the seat's calls with a
Generalized Mind Instance (docs/GMI.md, "GMIs from agent()"). agency() throws
AgencyConfigError, naming the seat, for any other value; null is unset, so the
agency's runtime applies.
Optional cognitionGMI profile when runtime is 'gmi', validated each time a run builds the
seat. The strategies call a seat's generate() and stream(), which run the
'light' profile whatever this option names.
Optional fromNames of pool entries this seat may sit on, in preference order. Default: every entry, in pool order.
Optional vendorFor a fixed seat: who trained its model, when that cannot be read from its provider and model id.
Optional fallbackA fixed seat's own failover chain. Replaces the default for this seat. Rejected on a pooled seat.
Optional onCalled when a fixed seat's call moves to a hop of its chain. Rejected on a pooled seat.
A roster seat of
agency()written as a config. The agency builds the seat withagent(), so the two options that pick an agent's engine are read on a seat asagent()reads them. In an agency with amodelPool, a seat that names neitherprovidernormodelis filled from the pool on every call, from the entriesfromnames.Example