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Sweep 22 Sep 2026 · 15:52Z Build v2.1.280 501 read Stable v2.1.267 Latest v2.1.280 Next v2.1.280 Feeds RSS JSON llms.txt Unofficial
Writing the changelog v2.1.280 merge candidates · 1/5
HomePrompts
Prompt capture

v2.1.280, what moved

CLI Claude Code, interactive mode. 2 added and 2 removed, of 218 lines, about 12 words, in the prompt 17 of 27 arms receive. 3 other prompts also changed. The appended system-reminder blocks moved: 2 lines added, 1 line removed. Compared against v2.1.278.

The two arm counts on this page measure different things: 17 arms receive the prompt the headline is about, and the widest edit below reached 23, because the same changed lines sit in more than one prompt.

Releasedcaptured
Compared withv2.1.278the previous capture on this arm
Prompt218 ln4 families, 27,325 characters
Model strings27every capture asks all of them
Tool descriptions27 0 moved this release, 25 with a parameter schema
Appended after it10 blocks87,898 more characters on the wire This changeas markdownfor diffing it yourself
Claude Code, interactive mode Agent SDK, print mode Claude Code, interactive mode, seeded with flags-account Claude Code, interactive mode, seeded with flags-anon Agent SDK, print mode, seeded with flags-account Agent SDK, print mode, seeded with flags-anon
6 capture arms for this release, one page each, never diffed against each other

What changed since the previous capture

2 One line per document that moved, the system prompt and the tool descriptions in the same table.
PromptReachMovedThe first line that changed
System prompt 218 ln, and 1 other copy of it moved the same way 23 of 27 arms +2−2 - The most recent Claude models are the Claude 5 family and Haiku 4.5. Model IDs — Fable 5.1: 'claude-fable-5-1', Opus 5: 'claude-opus-5', Sonnet 5:...
System prompt 56 ln 4 of 27 arms +2−16 - The most recent Claude models are the Claude 5 family and Haiku 4.5. Model IDs — Fable 5.1: 'claude-fable-5-1', Opus 5: 'claude-opus-5', Sonnet 5:...

The families in this capture

4 A family is one prompt and every model-interpolated copy of it, ranked by the model strings it reaches.
#FamilyHeadReachCopiesOpens with
1 Haiku family, 12 model strings 218 ln · 27.3k 17 of 27 3 copies You are an interactive agent that helps users with software engineering tasks.
2 claude-fable-5 79 ln · 10.2k 2 of 27 2 copies You are an interactive agent that helps users with software engineering tasks.
3 Opus 5 family, 2 model strings 70 ln · 9.3k 2 of 27 1 copy You are an interactive agent that helps users with software engineering tasks.
4 Opus 4.0 family, 5 model strings 56 ln · 5.9k 6 of 27 2 copies You are an interactive agent that helps users with software engineering tasks.

Tool descriptions

27 The text the model is given for each tool, on this arm.
All 27 tool descriptions →
ToolDescriptionCopiesMoved
Agent 1,811 chars 2 ○same
AskUserQuestion 1,786 chars 2 ○same
Bash 1,229 chars 2 ○same
CronCreate 2,924 chars 1 ○same
CronDelete 167 chars 1 ○same
CronList 106 chars 1 ○same
Edit 360 chars 2 ○same
EnterPlanMode 4,011 chars 1 ○same
EnterWorktree 3,220 chars 1 ○same
ExitPlanMode 1,849 chars 1 ○same
ExitWorktree 1,923 chars 1 ○same
ListAgents 777 chars 1 ○same
NotebookEdit 619 chars 1 ○same
Read 790 chars 2 ○same
ReportFindings 574 chars 1 ○same
ScheduleWakeup 3,396 chars 1 ○same
SendMessage 4,259 chars 1 ○same
Skill 1,417 chars 1 ○same
TaskCreate 2,146 chars 1 ○same
TaskGet 732 chars 1 ○same
TaskList 998 chars 1 ○same
TaskStop 378 chars 1 ○same
TaskUpdate 2,243 chars 1 ○same
WebFetch 469 chars 2 ○same
WebSearch 312 chars 2 ○same
Workflow 3,480 chars 1 ○same
Write 240 chars 2 ○same
Read the whole system prompt → - The most recent Claude models are the Claude 5 family and Haiku 4.5. Model IDs — Fable 5.1: 'claude-fable-5-1', Opus 5...