Create Session changedapi/beta/sessions/create
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181
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from line 181, old and new numbered
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from line 181
181181
182182 Replacement model. Accepts the model string, e.g. `claude-opus-5`, or a `model_config` object. Omit to use the agent's model.
183183
184 - `BetaManagedAgentsModel = "claude-opus-5-5" or "claude-fable-5-1" or "claude-sonnet-5" or 12 more or string`
184 - `BetaManagedAgentsModel = string or "claude-opus-5-5" or "claude-fable-5-1" or "claude-sonnet-5" or 12 more`
185185
186186 The model that will power your agent.
187187
188188 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
189189
190 - `string`
191
190192 - `"claude-opus-5-5" or "claude-fable-5-1" or "claude-sonnet-5" or 12 more`
191193
192194 The model that will power your agent.
from line 255
253255
254256 High-performance model for agents and coding
255257
256 - `string`
257
258258 - `BetaManagedAgentsModelConfigParams object`
259259
260260 An object that defines additional configuration control over model use
from line 329
329329
330330 - `speed: optional "standard" or "fast" or null`
331331
332 Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.
332 Inference speed mode. Defaults to `standard`.
333333
334334 - `"standard"`
335335
from line 411
411411
412412 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
413413
414 Permission policy for tool execution.
414 Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation.
415415
416416 - `BetaManagedAgentsAlwaysAllowPolicy object`
417417
from line 447
447447
448448 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
449449
450 Permission policy for tool execution.
450 Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation.
451451
452452 - `BetaManagedAgentsAlwaysAllowPolicy object`
453453
from line 477
477477
478478 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
479479
480 Permission policy for tool execution.
480 Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation.
481481
482482 - `BetaManagedAgentsAlwaysAllowPolicy object`
483483
from line 507
507507
508508 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
509509
510 Permission policy for tool execution.
510 Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation.
511511
512512 - `BetaManagedAgentsAlwaysAllowPolicy object`
513513
from line 537
537537
538538 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
539539
540 Permission policy for tool execution.
540 Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation.
541541
542542 - `BetaManagedAgentsAlwaysAllowPolicy object`
543543
from line 567
567567
568568 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
569569
570 Permission policy for tool execution.
570 Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation.
571571
572572 - `BetaManagedAgentsAlwaysAllowPolicy object`
573573
from line 611
611611
612612 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
613613
614 Permission policy for tool execution.
614 Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation.
615615
616616 - `BetaManagedAgentsAlwaysAllowPolicy object`
617617
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649649
650650 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
651651
652 Permission policy for tool execution.
652 Permission policy for this tool. Controls whether tool calls are auto-approved or require confirmation.
653653
654654 - `BetaManagedAgentsAlwaysAllowPolicy object`
655655
from line 695
695695
696696 - `default_config: optional BetaManagedAgentsAgentToolsetDefaultConfigParams or null`
697697
698 Default configuration for all tools in a toolset.
698 Default configuration applied to all tools in this set.
699699
700700 - `enabled: optional boolean or null`
701701
from line 703
703703
704704 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
705705
706 Permission policy for tool execution.
706 Default permission policy for tools. Controls whether tool calls are auto-approved or require confirmation.
707707
708708 - `BetaManagedAgentsAlwaysAllowPolicy object`
709709
from line 745
745745
746746 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
747747
748 Permission policy for tool execution.
748 Permission policy for this tool. Overrides the `default_config` setting.
749749
750750 - `BetaManagedAgentsAlwaysAllowPolicy object`
751751
from line 761
761761
762762 - `default_config: optional BetaManagedAgentsMCPToolsetDefaultConfigParams or null`
763763
764 Default configuration for all tools from an MCP server.
764 Default configuration for all tools from this server.
765765
766766 - `enabled: optional boolean or null`
767767
from line 769
769769
770770 - `permission_policy: optional BetaManagedAgentsAlwaysAllowPolicy or BetaManagedAgentsAlwaysAskPolicy or BetaManagedAgentsAutoPolicy or null`
771771
772 Permission policy for tool execution.
772 Default permission policy for tools from this server.
773773
774774 - `BetaManagedAgentsAlwaysAllowPolicy object`
775775
from line 797
797797
798798 - `input_schema: BetaManagedAgentsCustomToolInputSchema`
799799
800 JSON Schema for custom tool input parameters.
800 JSON Schema defining the expected input parameters for the tool.
801801
802802 - `type: "object"`
803803
from line 825
825825
826826- `budget: optional BetaManagedAgentsBudgetLimit`
827827
828 A hard spend ceiling. The session stops issuing new model requests once the tracked list cost reaches `max_list_cost`.
828 Enforced spend ceiling for the session. Omit to create an uncapped session. Every model the session can run — the agent's model and each callable agent's model — must have a public list price, or the request is rejected with reason `model_not_budgetable`.
829829
830830 - `type: "limit"`
831831
832832 - `max_list_cost: BetaMonetaryAmount`
833833
834 A monetary amount in a specific currency.
834 Maximum list cost the session may accrue. List price is used regardless of any negotiated discount, so the cap fires at or before the actual charge.
835835
836836 - `amount: string`
837837
from line 875
875875
876876 - `source: BetaManagedAgentsBase64ImageSource or BetaManagedAgentsURLImageSource or BetaManagedAgentsFileImageSource`
877877
878 Union type for image source variants.
878 The source of the image data.
879879
880880 - `BetaManagedAgentsBase64ImageSource object`
881881
from line 927
927927
928928 - `source: BetaManagedAgentsBase64DocumentSource or BetaManagedAgentsPlainTextDocumentSource or BetaManagedAgentsURLDocumentSource or BetaManagedAgentsFileDocumentSource`
929929
930 Union type for document source variants.
930 The source of the document data.
931931
932932 - `BetaManagedAgentsBase64DocumentSource object`
933933
from line 1013
10131013
10141014 - `rubric: BetaManagedAgentsFileRubricParams or BetaManagedAgentsTextRubricParams`
10151015
1016 Rubric for grading the quality of an outcome.
1016 How to grade the outcome. Text or file reference.
10171017
10181018 - `BetaManagedAgentsFileRubricParams object`
10191019
from line 1129
11291129
11301130 - `access: optional "read_write" or "read_only" or null`
11311131
1132 Access mode for an attached memory store.
1132 Access mode for the mounted store. Defaults to read_write. read_only mounts the store as a read-only filesystem.
11331133
11341134 - `"read_write"`
11351135
from line 1189
11891189
11901190 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
11911191
1192 - `string`
1193
11921194 - `"claude-opus-5-5" or "claude-fable-5-1" or "claude-sonnet-5" or 12 more`
11931195
11941196 The model that will power your agent.
from line 1257
12551257
12561258 High-performance model for agents and coding
12571259
1258 - `string`
1259
12601260 - `effort: optional BetaManagedAgentsEffortLow or BetaManagedAgentsEffortMedium or BetaManagedAgentsEffortHigh or 2 more`
12611261
1262 How hard Claude works on each turn. Sets `output_config.effort` on every Messages call the session makes.
1262 How hard Claude works on each inference call. One of `low`, `medium`, `high`, `xhigh`, `max`. Always present; resolved to the per-model default at save time when not supplied.
12631263
12641264 - `BetaManagedAgentsEffortLow object`
12651265
from line 1297
12971297
12981298 - `speed: optional "standard" or "fast"`
12991299
1300 Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.
1300 Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Defaults to `standard`. Not all models support `fast`; invalid combinations are rejected at create time.
13011301
13021302 - `"standard"`
13031303
from line 1305
13051305
13061306 - `multiagent: BetaManagedAgentsSessionMultiagentCoordinator or null`
13071307
1308 Resolved coordinator topology with full agent definitions for each roster member.
1308 Resolved multiagent orchestration configuration. Null when the agent is single-threaded.
13091309
13101310 - `type: "coordinator"`
13111311
from line 1761
17611761
17621762 - `archived_at: string or null`
17631763
1764 A timestamp in RFC 3339 format
1764 When the session was archived. Null if not archived.
17651765
17661766 format: date-time
17671767
17681768 - `budget: BetaManagedAgentsBudgetLimit or null`
17691769
1770 A hard spend ceiling. The session stops issuing new model requests once the tracked list cost reaches `max_list_cost`.
1770 The session's enforced spend ceiling, or null when no budget is set.
17711771
17721772 - `type: "limit"`
17731773
17741774 - `max_list_cost: BetaMonetaryAmount`
17751775
1776 A monetary amount in a specific currency.
1776 Maximum list cost the session may accrue. List price is used regardless of any negotiated discount, so the cap fires at or before the actual charge.
17771777
17781778 - `amount: string`
17791779
from line 1801
18011801
18021802 - `completed_at: string or null`
18031803
1804 A timestamp in RFC 3339 format
1804 When the outcome reached a terminal result. Null while `pending`/`running`/`evaluating`.
18051805
18061806 format: date-time
18071807
from line 1907
19071907
19081908 - `access: optional "read_write" or "read_only" or null`
19091909
1910 Access mode for an attached memory store.
1910 Access mode for the mounted store. Defaults to `read_write`. `read_only` mounts the store as a read-only filesystem.
19111911
19121912 - `"read_write"`
19131913
from line 1933
19331933
19341934 - `stats: BetaManagedAgentsSessionStats`
19351935
1936 Timing statistics for a session.
1936 Timing statistics for the session.
19371937
19381938 - `active_seconds: optional number`
19391939
from line 1977
19771977
19781978 - `usage: BetaManagedAgentsSessionUsage`
19791979
1980 Cumulative token usage for a session across all turns.
1980 Cumulative token usage for the session.
19811981
19821982 - `active_seconds: optional number`
19831983
from line 1987
19871987
19881988 - `cache_creation: optional BetaManagedAgentsCacheCreationUsage`
19891989
1990 Prompt-cache creation token usage broken down by cache lifetime.
1990 Tokens used to create prompt cache entries, broken down by cache TTL.
19911991
19921992 - `ephemeral_1h_input_tokens: optional number`
19931993
from line 2015
20152015
20162016 - `list_cost: optional BetaMonetaryAmount or null`
20172017
2018 A monetary amount in a specific currency.
2018 Cumulative list cost of the session across all turns, priced at public list rates. Absent until cost tracking is available for the session.
20192019
20202020 - `output_tokens: optional number`
20212021
from line 2025
20252025
20262026 - `server_tool_use: optional BetaManagedAgentsServerToolUsage or null`
20272027
2028 Cumulative count of server-executed tool invocations, broken down by tool.
2028 Cumulative server-executed tool usage across all turns. Absent until server-tool tracking is available for the session.
20292029
20302030 - `web_fetch_requests: optional number`
20312031
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