Sweep 22 Sep 2026 · 17:19Z Build v2.1.280 501 read Stable v2.1.267 Latest v2.1.280 Next v2.1.280 Feeds RSS JSON llms.txt Unofficial
One change · api

strict-tool-use changed

agents-and-tools/tool-use/strict-tool-use

Nearest release: v2.1.280, 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+27added
Lines−27removed
From line 34 where the diff opens
First seen 14 Aug 2026 this site's first read of the page
Recorded edits4to this page, all time

The whole hunk

from line 34, old and new numbered
/
lines
from line 34
3434 -H "x-api-key: $ANTHROPIC_API_KEY" \
3535 -H "anthropic-version: 2023-06-01" \
3636 -d '{
37 "model": "claude-opus-5",
37 "model": "claude-opus-5-5",
3838 "max_tokens": 1024,
3939 "messages": [
4040 {"role": "user", "content": "What is the weather in San Francisco?"}
from line 64
6464 
6565 ```bash CLI
6666 ant messages create --transform content <<'YAML'
67 model: claude-opus-5
67 model: claude-opus-5-5
6868 max_tokens: 1024
6969 messages:
7070 - role: user
from line 91
9191 client = anthropic.Anthropic()
9292 
9393 response = client.messages.create(
94 model="claude-opus-5",
94 model="claude-opus-5-5",
9595 max_tokens=1024,
9696 messages=[{"role": "user", "content": "What's the weather like in San Francisco?"}],
9797 tools=[
from line 127
127127 });
128128 
129129 const response = await client.messages.create({
130 model: "claude-opus-5",
130 model: "claude-opus-5-5",
131131 max_tokens: 1024,
132132 messages: [
133133 {
from line 170
170170 
171171 var parameters = new MessageCreateParams
172172 {
173 Model = Model.ClaudeOpus5,
173 Model = Model.ClaudeOpus5_5,
174174 MaxTokens = 1024,
175175 Messages = [new() { Role = Role.User, Content = "What's the weather like in San Francisco?" }],
176176 Tools = [
from line 201
201201 client := anthropic.NewClient()
202202 
203203 response, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
204 Model: anthropic.ModelClaudeOpus5,
204 Model: anthropic.ModelClaudeOpus5_5,
205205 MaxTokens: 1024,
206206 Messages: []anthropic.MessageParam{
207207 anthropic.NewUserMessage(anthropic.NewTextBlock("What's the weather like in San Francisco?")),
from line 258
258258 .build();
259259 
260260 MessageCreateParams params = MessageCreateParams.builder()
261 .model(Model.CLAUDE_OPUS_5)
261 .model(Model.CLAUDE_OPUS_5_5)
262262 .maxTokens(1024L)
263263 .addUserMessage("What's the weather like in San Francisco?")
264264 .addTool(
from line 283
283283 messages: [
284284 ['role' => 'user', 'content' => "What's the weather like in San Francisco?"]
285285 ],
286 model: 'claude-opus-5',
286 model: 'claude-opus-5-5',
287287 tools: [
288288 [
289289 'name' => 'get_weather',
from line 315
315315 client = Anthropic::Client.new
316316 
317317 message = client.messages.create(
318 model: "claude-opus-5",
318 model: "claude-opus-5-5",
319319 max_tokens: 1024,
320320 messages: [
321321 { role: "user", content: "What's the weather like in San Francisco?" }
from line 395
395395 -H "x-api-key: $ANTHROPIC_API_KEY" \
396396 -H "anthropic-version: 2023-06-01" \
397397 -d '{
398 "model": "claude-opus-5",
398 "model": "claude-opus-5-5",
399399 "max_tokens": 1024,
400400 "messages": [
401401 {"role": "user", "content": "Search for flights to Tokyo departing June 1, 2026"}
from line 419
419419 
420420 ```bash CLI
421421 ant messages create <<'YAML'
422 model: claude-opus-5
422 model: claude-opus-5-5
423423 max_tokens: 1024
424424 messages:
425425 - role: user
from line 446
446446 ```python Python
447447 client = Anthropic()
448448 response = client.messages.create(
449 model="claude-opus-5",
449 model="claude-opus-5-5",
450450 max_tokens=1024,
451451 messages=[
452452 {
from line 497
497497 };
498498 
499499 const response = await client.messages.create({
500 model: "claude-opus-5",
500 model: "claude-opus-5-5",
501501 max_tokens: 1024,
502502 messages: [{ role: "user", content: "Search for flights to Tokyo departing June 1, 2026" }],
503503 tools: [searchFlightsTool]
from line 515
515515 
516516 var parameters = new MessageCreateParams
517517 {
518 Model = Model.ClaudeOpus5,
518 Model = Model.ClaudeOpus5_5,
519519 MaxTokens = 1024,
520520 Messages = [new() { Role = Role.User, Content = "Search for flights to Tokyo departing June 1, 2026" }],
521521 Tools = [
from line 546
546546 client := anthropic.NewClient()
547547 
548548 response, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
549 Model: anthropic.ModelClaudeOpus5,
549 Model: anthropic.ModelClaudeOpus5_5,
550550 MaxTokens: 1024,
551551 Messages: []anthropic.MessageParam{
552552 anthropic.NewUserMessage(anthropic.NewTextBlock("Search for flights to Tokyo departing June 1, 2026")),
from line 603
603603 .build();
604604 
605605 MessageCreateParams params = MessageCreateParams.builder()
606 .model(Model.CLAUDE_OPUS_5)
606 .model(Model.CLAUDE_OPUS_5_5)
607607 .maxTokens(1024L)
608608 .addUserMessage("Search for flights to Tokyo departing June 1, 2026")
609609 .addTool(
from line 627
627627 messages: [
628628 ['role' => 'user', 'content' => 'Search for flights to Tokyo departing June 1, 2026']
629629 ],
630 model: 'claude-opus-5',
630 model: 'claude-opus-5-5',
631631 tools: [
632632 [
633633 'name' => 'search_flights',
from line 656
656656 client = Anthropic::Client.new
657657 
658658 message = client.messages.create(
659 model: "claude-opus-5",
659 model: "claude-opus-5-5",
660660 max_tokens: 1024,
661661 messages: [
662662 { role: "user", content: "Search for flights to Tokyo departing June 1, 2026" }
from line 696
696696 -H "x-api-key: $ANTHROPIC_API_KEY" \
697697 -H "anthropic-version: 2023-06-01" \
698698 -d '{
699 "model": "claude-opus-5",
699 "model": "claude-opus-5-5",
700700 "max_tokens": 1024,
701701 "messages": [
702702 {"role": "user", "content": "Help me plan a trip from New York to Paris for 2 people, departing June 1, 2026"}
from line 737
737737 
738738 ```bash CLI
739739 ant messages create <<'YAML'
740 model: claude-opus-5
740 model: claude-opus-5-5
741741 max_tokens: 1024
742742 messages:
743743 - role: user
from line 772
772772 ```python Python
773773 client = Anthropic()
774774 response = client.messages.create(
775 model="claude-opus-5",
775 model="claude-opus-5-5",
776776 max_tokens=1024,
777777 messages=[
778778 {
from line 852
852852 ];
853853 
854854 const response = await client.messages.create({
855 model: "claude-opus-5",
855 model: "claude-opus-5-5",
856856 max_tokens: 1024,
857857 messages: [
858858 {
from line 876
876876 
877877 var parameters = new MessageCreateParams
878878 {
879 Model = Model.ClaudeOpus5,
879 Model = Model.ClaudeOpus5_5,
880880 MaxTokens = 1024,
881881 Messages = [new() { Role = Role.User, Content = "Help me plan a trip from New York to Paris for 2 people, departing June 1, 2026" }],
882882 Tools = [
from line 924
924924 client := anthropic.NewClient()
925925 
926926 response, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
927 Model: anthropic.ModelClaudeOpus5,
927 Model: anthropic.ModelClaudeOpus5_5,
928928 MaxTokens: 1024,
929929 Messages: []anthropic.MessageParam{
930930 anthropic.NewUserMessage(anthropic.NewTextBlock("Help me plan a trip from New York to Paris for 2 people, departing June 1, 2026")),
from line 1000
10001000 .build();
10011001 
10021002 MessageCreateParams params = MessageCreateParams.builder()
1003 .model(Model.CLAUDE_OPUS_5)
1003 .model(Model.CLAUDE_OPUS_5_5)
10041004 .maxTokens(1024L)
10051005 .addUserMessage("Help me plan a trip from New York to Paris for 2 people, departing June 1, 2026")
10061006 .addTool(
from line 1031
10311031 messages: [
10321032 ['role' => 'user', 'content' => 'Help me plan a trip from New York to Paris for 2 people, departing June 1, 2026']
10331033 ],
1034 model: 'claude-opus-5',
1034 model: 'claude-opus-5-5',
10351035 tools: [
10361036 [
10371037 'name' => 'search_flights',
from line 1072
10721072 client = Anthropic::Client.new
10731073 
10741074 message = client.messages.create(
1075 model: "claude-opus-5",
1075 model: "claude-opus-5-5",
10761076 max_tokens: 1024,
10771077 messages: [
10781078 { role: "user", content: "Help me plan a trip from New York to Paris for 2 people, departing June 1, 2026" }