Platform advisor roster entry: a model the session's primary thread may consult mid-turn. At most one per roster; the entry occupies the roster name anthropic.advisor.

model: string

A Claude model id. The model must be permitted as an advisor for this agent's model — see the sessions/threads/advisor spec.

minLength1

maxLength256

type: "advisor"

BetaManagedAgentsAgentMessagePreview { id, type }

id: string

The id the buffered agent.message will carry if it is emitted. Matches the event_id on this preview's event_delta events.

type: "agent.message"

BetaManagedAgentsAgentParams { id, type, version }

Specification for an Agent. Provide a specific version or use the short-form agent="agent_id" for the most recent version

id: string

The agent ID.

minLength1

maxLength128

type: "agent"

version?: number

The specific agent version to use. Omit to use the latest version. Must be at least 1 if specified.

formatint32

BetaManagedAgentsAgentThinkingPreview { id, type }

id: string

The id the buffered agent.thinking will carry if it is emitted. Start-only — no event_delta events follow.

type: "agent.thinking"

BetaManagedAgentsAgentWithOverridesParams { id, type, mcp_servers, 5 more }

Reference to an agent plus optional configuration overrides. Each provided field replaces the agent's value for the caller's use; the agent resource is unchanged.

BetaManagedAgentsBranchCheckout { name, type }

name: string

Branch name to check out.

minLength1

maxLength255

type: "branch"

BetaManagedAgentsBudgetLimit { max_list_cost, type }

A hard spend ceiling. The session stops issuing new model requests once the tracked list cost reaches max_list_cost.

max_list_cost: BetaMonetaryAmount { amount, currency }

A monetary amount in a specific currency.

amount: string

Amount in minor units of the currency, as an integer decimal string with no leading zeros: "2500" is $25.00 and "50" is fifty cents. A string rather than a number so no float rounding is ever applied.

currency: BetaCurrency

Uppercase ISO-4217 currency code. USD is the only currency currently supported; the accepted set is closed and grows only when a new currency is priced.

type: "limit"

BetaManagedAgentsCacheCreationUsage { ephemeral_1h_input_tokens, ephemeral_5m_input_tokens }

Prompt-cache creation token usage broken down by cache lifetime.

ephemeral_1h_input_tokens?: number

Tokens used to create 1-hour ephemeral cache entries.

formatint32

ephemeral_5m_input_tokens?: number

Tokens used to create 5-minute ephemeral cache entries.

formatint32

BetaManagedAgentsCommitCheckout { sha, type }

sha: string

Full commit SHA to check out.

minLength7

maxLength64

type: "commit"

BetaManagedAgentsDeletedSession { id, type }

Confirmation that a session has been permanently deleted.

id: string

type: "session_deleted"

BetaManagedAgentsDeltaContent { content, type, index }

content: BetaManagedAgentsTextBlock { text, type }

Regular text content.

text: string

The text content.

minLength1

type: "text"

type: "content_delta"

index?: number

Which entry in the previewed event's content array this fragment lands in. Insert content as that entry when the index is new; append to the existing entry otherwise.

formatuint32

BetaManagedAgentsDeltaEvent { delta, event_id, type }

An incremental update to an event that is still being streamed. Deltas are best-effort and may stop early; when the buffered event with id == event_id is produced it carries the complete content. A model request that ends early (an error or interrupt) produces no buffered event — its terminal span.model_request_end closes the preview. Only sent on stream connections that opt in via event_deltas; never appears in event history.

delta: BetaManagedAgentsDeltaContent { content, type, index }

One fragment of the previewed event. The delta type is named for the previewed event's field it streams into: agent.message events stream content_delta fragments, each a partial element of the content array.

content: BetaManagedAgentsTextBlock { text, type }

Regular text content.

text: string

The text content.

minLength1

type: "text"

type: "content_delta"

index?: number

Which entry in the previewed event's content array this fragment lands in. Insert content as that entry when the index is new; append to the existing entry otherwise.

formatuint32

event_id: string

The id of the event being previewed. Matches event.id on the corresponding event_start and the buffered event that reconciles the preview.

type: "event_delta"

BetaManagedAgentsDeltaType = "agent.message" | "agent.thinking"

EventDeltaType enum

One of the following:

"agent.message"

"agent.thinking"

BetaManagedAgentsFileResourceParams { file_id, type, mount_path }

Mount a file uploaded via the Files API into the session.

file_id: string

ID of a previously uploaded file.

minLength1

maxLength128

type: "file"

mount_path?: string | null

Mount path in the container. Defaults to /mnt/session/uploads/<file_id>.

minLength1

maxLength4096

BetaManagedAgentsGitHubRepositoryResourceParams { authorization_token, type, url, 2 more }

Mount a GitHub repository into the session's container.

BetaManagedAgentsMemoryStoreResourceParam { memory_store_id, type, access, instructions }

Parameters for attaching a memory store to an agent session.

memory_store_id: string

The memory store ID (memstore_...). Must belong to the caller's organization and workspace.

type: "memory_store"

access?: "read_write" | "read_only" | null

Access mode for an attached memory store.

One of the following:

"read_write"

"read_only"

instructions?: string | null

Per-attachment guidance for the agent on how to use this store. Rendered into the memory section of the system prompt. Max 4096 chars.

maxLength4096

BetaManagedAgentsMultiagent { agents, type }

Resolved coordinator topology with a concrete agent roster.

BetaManagedAgentsMultiagentParams { agents, type }

A coordinator topology: the session's primary thread orchestrates work by spawning session threads, each running an agent drawn from the agents roster.

BetaManagedAgentsMultiagentRosterEntryParams = string | BetaManagedAgentsAgentParams { id, type, version } | BetaManagedAgentsMultiagentSelfParams { type } | BetaManagedAgentsAdvisorParams { model, type }

An entry in a multiagent roster: an agent ID string, a versioned agent reference, or self.

One of the following:

BetaManagedAgentsOutcomeEvaluationResource { completed_at, description, explanation, 4 more }

Evaluation state for a single outcome defined via a define_outcome event.

completed_at: string | null

A timestamp in RFC 3339 format

formatdate-time

description: string

What the agent should produce.

explanation: string | null

Grader's verdict text from the most recent evaluation. For satisfied, explains why criteria are met; for needs_revision (intermediate), what's missing; for failed, why unrecoverable.

iteration: number

0-indexed revision cycle the outcome is currently on.

formatint32

outcome_id: string

Server-generated outc_ ID for this outcome.

result: string

Current evaluation state. pending before the agent begins work; running while producing or revising; evaluating while the grader scores; satisfied/max_iterations_reached/failed/interrupted are terminal.

type: "outcome_evaluation"

BetaManagedAgentsServerToolUsage { web_fetch_requests, web_search_requests }

Cumulative count of server-executed tool invocations, broken down by tool.

web_fetch_requests?: number

Number of server-executed web fetch requests.

formatint32

web_search_requests?: number

Number of server-executed web search requests.

formatint32

BetaManagedAgentsSession { id, agent, archived_at, 14 more }

A Managed Agents session.

BetaManagedAgentsSessionAgent { id, description, mcp_servers, 8 more }

Resolved agent definition for a session. Snapshot of the agent at session creation time.

BetaManagedAgentsSessionAgentUpdate { mcp_servers, tools }

Mid-session agent configuration update. Only tools and mcp_servers are updatable. Full replacement: the provided array becomes the new value. To preserve existing entries, GET the session, modify the array, and POST it back.

BetaManagedAgentsSessionMultiagentCoordinator { agents, type }

Resolved coordinator topology with full agent definitions for each roster member.

BetaManagedAgentsSessionStats { active_seconds, duration_seconds }

Timing statistics for a session.

active_seconds?: number

Cumulative time in seconds the session spent in running status. Excludes idle time.

formatdouble

duration_seconds?: number

Elapsed time since session creation in seconds. For terminated sessions, frozen at the final update.

formatdouble

BetaManagedAgentsSessionUpdatedEvent { id, processed_at, type, 4 more }

Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

BetaManagedAgentsSessionUsage { active_seconds, cache_creation, cache_read_input_tokens, 4 more }

Cumulative token usage for a session across all turns.

BetaManagedAgentsSessionUsageEvent { id, processed_at, type, 2 more }

Periodic snapshot of the session's cumulative usage and tracked list cost.

BetaManagedAgentsStartEvent { event, type }

Opens a preview of a buffered event. Carries the previewed event's type and id only. Followed by zero or more event_delta events with the same event id, normally concluded by the buffered event carrying that id. If the producing model request ends without that event (an error or interrupt mid-stream), its terminal span.model_request_end closes the preview. Only sent on stream connections that opt in via event_deltas; never appears in event history.

event: BetaManagedAgentsStartEventPreview

The previewed event's type and id. The event type determines which delta types the preview's event_delta events carry: agent.message events stream content_delta fragments; agent.thinking previews are start-only — no deltas follow, and the buffered agent.thinking with the same id concludes them.

One of the following:

BetaManagedAgentsAgentMessagePreview { id, type }

id: string

The id the buffered agent.message will carry if it is emitted. Matches the event_id on this preview's event_delta events.

type: "agent.message"

BetaManagedAgentsAgentThinkingPreview { id, type }

id: string

The id the buffered agent.thinking will carry if it is emitted. Start-only — no event_delta events follow.

type: "agent.thinking"

type: "event_start"

BetaManagedAgentsStartEventPreview = BetaManagedAgentsAgentMessagePreview { id, type } | BetaManagedAgentsAgentThinkingPreview { id, type }

One of the following:

BetaManagedAgentsAgentMessagePreview { id, type }

id: string

The id the buffered agent.message will carry if it is emitted. Matches the event_id on this preview's event_delta events.

type: "agent.message"

BetaManagedAgentsAgentThinkingPreview { id, type }

id: string

The id the buffered agent.thinking will carry if it is emitted. Start-only — no event_delta events follow.

type: "agent.thinking"

BetaManagedAgentsSystemContentBlock { text, type }

Regular text content.

text: string

The text content.

minLength1

type: "text"

BetaManagedAgentsSystemMessageEvent { id, content, type, processed_at }

A mid-conversation system message event. Carries system-role content that is appended to the session as a role: "system" turn.

id: string

Unique identifier for this event.

content: Array<BetaManagedAgentsSystemContentBlock { text, type }>

System content blocks. Text-only.

text: string

The text content.

minLength1

type: "text"

type: "system.message"

processed_at?: string | null

A timestamp in RFC 3339 format

formatdate-time

BetaManagedAgentsUserToolResultEvent { id, tool_use_id, type, 4 more }

Event sent by the client providing the result of an agent-toolset tool execution. Only valid on self_hosted environments, where sandbox-routed tools are executed by the client rather than the server.

SessionsResources

SessionsThreadsEvents

List Session Thread Events

client.beta.sessions.threads.events.list(, , ?): PageCursor<BetaManagedAgentsSessionEvent>

GET/v1/sessions/{session_id}/threads/{thread_id}/events

Stream Session Thread Events

client.beta.sessions.threads.events.stream(, , ?): BetaManagedAgentsStreamSessionThreadEvents | Stream<BetaManagedAgentsStreamSessionThreadEvents>

GET/v1/sessions/{session_id}/threads/{thread_id}/stream

Sessions

Create Session

List Sessions

Get Session

Update Session

Delete Session

Archive Session

Models

SessionsEvents

List Events

Send Events

Stream Events

SessionsResources

Add Session Resource

List Session Resources

Get Session Resource

Update Session Resource

Delete Session Resource

SessionsThreads

List Session Threads

Get Session Thread

Archive Session Thread

SessionsThreadsEvents

List Session Thread Events

Stream Session Thread Events