Or, for Claude Mythos 5.1, which offers the same capabilities to verified organizations: changedmodels/fable-5-1/migration-guide
Nearest release: v2.1.301, published 5 hours 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+64added
Lines−70removed
From line
67
where the diff opens
First seen
1 Sep 2026
this site's first read of the page
Recorded edits25to this page, all time
The whole hunk
from line 67, old and new numbered
/
from line 67
6767 -H "content-type: application/json" \
6868 -H "x-api-key: $ANTHROPIC_API_KEY" \
6969 -H "anthropic-version: 2023-06-01" \
70 -d @- <<'EOF'
71 {
72 "model": "claude-fable-5",
73 "max_tokens": 16000,
74 "tools": [
75 {
76 "name": "record_summary",
77 "description": "Record the structured summary of the document.",
78 "input_schema": {
79 "type": "object",
80 "properties": {"summary": {"type": "string"}},
81 "required": ["summary"]
70 -d '{
71 "model": "claude-fable-5",
72 "max_tokens": 16000,
73 "tools": [
74 {
75 "name": "record_summary",
76 "description": "Record the structured summary of the document.",
77 "input_schema": {
78 "type": "object",
79 "properties": {"summary": {"type": "string"}},
80 "required": ["summary"]
81 }
8282 }
83 }
84 ],
85 "tool_choice": {"type": "tool", "name": "record_summary"},
86 "messages": [
87 {"role": "user", "content": "Summarize: The meeting moved to Thursday."}
88 ]
89 }
90 EOF
83 ],
84 "tool_choice": {"type": "tool", "name": "record_summary"},
85 "messages": [
86 {"role": "user", "content": "Summarize: The meeting moved to Thursday."}
87 ]
88 }'
9189 ```
9290
9391 ```bash CLI
from line 307
309307 -H "content-type: application/json" \
310308 -H "x-api-key: $ANTHROPIC_API_KEY" \
311309 -H "anthropic-version: 2023-06-01" \
312 -d @- <<'EOF'
313 {
314 "model": "claude-fable-5-1",
315 "max_tokens": 16000,
316 "tools": [
317 {
318 "name": "record_summary",
319 "description": "Record the structured summary of the document.",
320 "strict": true,
321 "input_schema": {
322 "type": "object",
323 "properties": {"summary": {"type": "string"}},
324 "required": ["summary"],
325 "additionalProperties": false
310 -d '{
311 "model": "claude-fable-5-1",
312 "max_tokens": 16000,
313 "tools": [
314 {
315 "name": "record_summary",
316 "description": "Record the structured summary of the document.",
317 "strict": true,
318 "input_schema": {
319 "type": "object",
320 "properties": {"summary": {"type": "string"}},
321 "required": ["summary"],
322 "additionalProperties": false
323 }
326324 }
327 }
328 ],
329 "tool_choice": {"type": "auto"},
330 "messages": [
331 {"role": "user", "content": "Summarize: The meeting moved to Thursday. Call the record_summary tool with your result."}
332 ]
333 }
334 EOF
325 ],
326 "tool_choice": {"type": "auto"},
327 "messages": [
328 {"role": "user", "content": "Summarize: The meeting moved to Thursday. Call the record_summary tool with your result."}
329 ]
330 }'
335331 ```
336332
337333 ```bash CLI
from line 577
581577 -H "content-type: application/json" \
582578 -H "x-api-key: $ANTHROPIC_API_KEY" \
583579 -H "anthropic-version: 2023-06-01" \
584 -d @- <<'EOF'
585 {
586 "model": "claude-fable-5-1",
587 "max_tokens": 16000,
588 "system": "You are a customer support assistant for an online electronics store.",
589 "tools": [
590 {
591 "name": "search_help_center",
592 "description": "Search the help center for policy and troubleshooting articles.",
593 "strict": true,
594 "input_schema": {
595 "type": "object",
596 "properties": {"query": {"type": "string"}},
597 "required": ["query"],
598 "additionalProperties": false
580 -d '{
581 "model": "claude-fable-5-1",
582 "max_tokens": 16000,
583 "system": "You are a customer support assistant for an online electronics store.",
584 "tools": [
585 {
586 "name": "search_help_center",
587 "description": "Search the help center for policy and troubleshooting articles.",
588 "strict": true,
589 "input_schema": {
590 "type": "object",
591 "properties": {"query": {"type": "string"}},
592 "required": ["query"],
593 "additionalProperties": false
594 }
599595 }
600 }
601 ],
602 "messages": [
603 {"role": "user", "content": "My headphones from order A1234 arrived yesterday."},
604 {"role": "assistant", "content": "Thanks for confirming. How can I help with order A1234?"},
605 {"role": "user", "content": "I opened the box. Can I still return them?"},
606 {
607 "role": "system",
608 "content": "Tool-use requirement for the current turn: the application requires a call to the search_help_center tool in your response to the user's latest message. Begin your response with the search_help_center tool call. Do not reply with text only."
609 }
610 ]
611 }
612 EOF
596 ],
597 "messages": [
598 {"role": "user", "content": "My headphones from order A1234 arrived yesterday."},
599 {"role": "assistant", "content": "Thanks for confirming. How can I help with order A1234?"},
600 {"role": "user", "content": "I opened the box. Can I still return them?"},
601 {
602 "role": "system",
603 "content": "Tool-use requirement for the current turn: the application requires a call to the search_help_center tool in your response to the latest message from the user. Begin your response with the search_help_center tool call. Do not reply with text only."
604 }
605 ]
606 }'
613607 ```
614608
615609 ```bash CLI
No line in this hunk matches that.