Delivering work changedbuild-with-claude/prompt-engineering/prompting-claude-fable-5-1
Nearest release: v2.1.302, 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+5added
Lines−3removed
From line
265
where the diff opens
First seen
1 Sep 2026
this site's first read of the page
Recorded edits10to this page, all time
The whole hunk
from line 265, old and new numbered
/
from line 265
265265 using System.Text.Json;
266266 using Anthropic;
267267 using Anthropic.Models.Beta.Messages;
268 using Model = Anthropic.Models.Messages.Model;
268269
269270 AnthropicClient client = new();
270271
from line 316
315316 {
316317 response = await client.Beta.Messages.Create(new MessageCreateParams
317318 {
318 Model = "claude-fable-5-1",
319 Model = Model.ClaudeFable5_1,
319320 MaxTokens = 16000,
320321 Betas = ["mid-conversation-system-clear-at-2026-08-21"],
321322 Tools = tools,
from line 430
429430 for {
430431 var err error
431432 response, err = client.Beta.Messages.New(ctx, anthropic.BetaMessageNewParams{
432 Model: "claude-fable-5-1",
433 Model: anthropic.ModelClaudeFable5_1,
433434 MaxTokens: 16000,
434435 Betas: []anthropic.AnthropicBeta{"mid-conversation-system-clear-at-2026-08-21"},
435436 Tools: tools,
from line 496
495496 import com.anthropic.models.beta.messages.BetaToolResultBlockParam;
496497 import com.anthropic.models.beta.messages.BetaToolUseBlock;
497498 import com.anthropic.models.beta.messages.MessageCreateParams;
499 import com.anthropic.models.messages.Model;
498500
499501 static final String BATCH_NUDGE =
500502 "First privately list what you need next; then request every item "
from line 536
534536 BetaMessage response;
535537 while (true) {
536538 response = client.beta().messages().create(MessageCreateParams.builder()
537 .model("claude-fable-5-1")
539 .model(Model.CLAUDE_FABLE_5_1)
538540 .maxTokens(16000)
539541 .addBeta("mid-conversation-system-clear-at-2026-08-21")
540542 .addTool(readFileTool)
No line in this hunk matches that.