Follow Discord
Sweep 10 Nov 2026 · 02:18Z Build v2.1.322 539 read Stable v2.1.311 Latest v2.1.322 Next v2.1.322 Feeds RSS JSON llms.txt llms-full.txt Unofficial
HomeDocsClaude Developer Platform 9 Nov 2026
One change · api

API usage primer for Claude changedclaude_api_primer

Nearest release: v2.1.321, published under an hour before 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+4added
Lines−2removed
From line 12 where the diff opens
First seen 14 Aug 2026 this site's first read of the page
Recorded edits25to this page, all time

The whole hunk

from line 12, old and new numbered
/
lines
from line 12
1212 
1313```text wrap
1414Recommended default for most work, including complex agentic coding: Claude Opus 5.5: claude-opus-5-5
15Step up for the hardest long-running agentic and research tasks, at 2.5x Claude Opus 5.5 pricing: Claude Fable 5.1: claude-fable-5-1
15Step up for the hardest long-running agentic and research tasks, at 2x Claude Opus 5.5 pricing: Claude Fable 5.2: claude-fable-5-2
1616Previous Opus model: Claude Opus 5: claude-opus-5
1717Smart model: Claude Sonnet 5.5: claude-sonnet-5-5
1818Previous Sonnet model: Claude Sonnet 5: claude-sonnet-5
from line 244
244244 
245245Thinking is supported in the following models:
246246 
247* Claude Fable 5.2 (`claude-fable-5-2`, adaptive thinking only, always on)
248* Claude Mythos 5.2 (`claude-mythos-5-2`, adaptive thinking only, always on)
247249* Claude Opus 5.5 (`claude-opus-5-5`, adaptive thinking only, always on)
248250* Claude Sonnet 5.5 (`claude-sonnet-5-5`, adaptive thinking only, on by default; `thinking: {"type": "disabled"}` returns a 400 error, so send `thinking: {"type": "between_tools"}` to turn off up-front thinking)
249251* Claude Haiku 5.5 (`claude-haiku-5-5`, adaptive thinking only, on by default)
from line 574
572574* `tool` forces Claude to always use a particular tool.
573575* `none` prevents Claude from using any tools.
574576 
575On Claude Opus 5.5, Claude Sonnet 5.5, Claude Fable 5.1, and Claude Mythos 5.1, `any` and `tool` return a 400 error. Leave `tool_choice` at `auto` and set `"strict": true` on the tool definition to guarantee that any call Claude makes matches the tool’s `input_schema`. See [Strict tool use](https://platform.claude.com/docs/en/agents-and-tools/tool-use/strict-tool-use).
577On Claude Fable 5.2, Claude Mythos 5.2, Claude Opus 5.5, Claude Sonnet 5.5, Claude Fable 5.1, and Claude Mythos 5.1, `any` and `tool` return a 400 error. Leave `tool_choice` at `auto` and set `"strict": true` on the tool definition to guarantee that any call Claude makes matches the tool’s `input_schema`. See [Strict tool use](https://platform.claude.com/docs/en/agents-and-tools/tool-use/strict-tool-use).
576578 
577579### JSON output
578580 
Feedback