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Sweep 06 Nov 2026 · 01:32Z Build v2.1.319 537 read Stable v2.1.311 Latest v2.1.319 Next v2.1.319 Feeds RSS JSON llms.txt llms-full.txt Unofficial
HomeDocsClaude Developer Platform 1 Sep 2026
One change · api

Count tokens in a Message changedapi/messages/count_tokens

Nearest release: v2.1.258, published an hour after this site recorded the change. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.

Recorded here
Lines+9added
Lines−21removed
From line 1,058 where the diff opens
First seen 14 Aug 2026 this site's first read of the page
Recorded edits22to this page, all time

The whole hunk

from line 1058, old and new numbered
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10581058 
10591059 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
10601060 
1061 - `"claude-sonnet-5" or "claude-fable-5" or "claude-mythos-5" or 12 more`
1061 - `"claude-fable-5-1" or "claude-mythos-5-1" or "claude-sonnet-5" or 14 more`
10621062 
10631063 The model that will complete your prompt.
10641064 
10651065 See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.
10661066 
1067 - `"claude-fable-5-1"`
1068 
1069 Frontier intelligence for ambitious tasks across coding, scientific discovery, and enterprise workflows
1070 
1071 - `"claude-mythos-5-1"`
1072 
1073 Our most capable model for cybersecurity and biology research, available through trusted access programs
1074 
10671075 - `"claude-sonnet-5"`
10681076 
10691077 High-performance model for coding and agents
from line 1581
15731581 
15741582 - `type: "browser_toolset_20260801"`
15751583 
1576 - `allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120" or "code_execution_20260521"`
1577 
1578 - `"direct"`
1579 
1580 - `"code_execution_20250825"`
1581 
1582 - `"code_execution_20260120"`
1583 
1584 - `"code_execution_20260521"`
1585 
15861584 - `cache_control: optional CacheControlEphemeral or null`
15871585 
15881586 Create a cache control breakpoint at this content block.
from line 2012
20142012 via `configs.zoom.enabled`.
20152013 
20162014 - `type: "computer_toolset_20260801"`
2017 
2018 - `allowed_callers: optional array of "direct" or "code_execution_20250825" or "code_execution_20260120" or "code_execution_20260521"`
2019 
2020 - `"direct"`
2021 
2022 - `"code_execution_20250825"`
2023 
2024 - `"code_execution_20260120"`
2025 
2026 - `"code_execution_20260521"`
20272015 
20282016 - `cache_control: optional CacheControlEphemeral or null`
20292017 
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