Anthropic: Claude Fable 5 (batch)
Claude Fable 5 is designed for complex reasoning, software engineering and research with multiple sequential stages. Supports extended tool use and analysis of visual material.
About the model
This description covers the model’s capabilities. Available in Ailoot inputs, outputs and options are listed for the selected method below.
A task that continues after the first answer
Claude Fable 5 is designed for demanding engineering and research work: analyzing a large problem, executing actions in sequence and evaluating the result. Anthropic highlights software engineering, professional analysis, visual understanding and extended autonomous tasks. The model can maintain the direction of its work as a task progresses through reading material, reasoning and using tools.
For this process, the manufacturer describes file-based memory: important information and working notes are stored outside the current conversation and used when work resumes. This capability requires reading and writing tools provided by the application. Context size and the model's name do not, by themselves, create persistent memory between independent requests.
From a scientific illustration to an engineering project
Fable 5 accepts text and images and produces its result as text. Visual scenarios include extracting numbers from detailed scientific illustrations and reconstructing an interface from a screenshot. In these tasks, an image gives the model data and a reference that it can connect to the instruction and use when writing code.
The manufacturer's standard visual input formats are JPEG/PNG/GIF/WebP, using the first frame of an animation. For native analysis, the longer dimension is 2576 pixels, with 4784 visual tokens; larger images are downscaled before analysis. File and parameter support depends on the application's method.
Anthropic also demonstrates tasks involving physical simulations, interactive programs and three-dimensional projects in an editor. Here, the model works through code and tools in the environment. To execute commands, modify files, control an editor and produce finished material, the application must provide the appropriate tools. These scenarios do not mean that a single text response independently generates images or three-dimensional files.
Always-on adaptive reasoning
Fable 5 has adaptive reasoning always enabled. Work depth is controlled by effort; the default level is high, with low, medium, xhigh and max also available. The model can perform additional analysis according to task complexity, including work with tool results. The original internal reasoning chain is not exposed; a brief summary is available when the application supports displaying it.
The context window is 1 million tokens, and the maximum response is 128 thousand tokens. The overall response limit must leave room for both reasoning and final text. The reliable built-in knowledge cutoff is January 2026.
An environment for sustained work
The manufacturer describes code execution, programmatic tool use, management of old action results and history compaction. These allow sustained workflows to be built when the application supports them. A task budget can guide the amount of work, but it does not replace the model's limits or the environment's constraints.
Safety mechanisms may decline sensitive requests.
When selecting settings in a method that supports them, the manufacturer's restrictions apply: continuation from a predefined response prefix and non-default values of temperature, top_p and top_k are not supported. In research and development, verifiable material and result criteria need to be retained: the ability to continue working does not guarantee that every conclusion or action is correct.
Ailoot Ultra · Batch POST /v1/batches anthropic/claude-fable-5:batch
anthropic/claude-fable-5:batch
anthropic/claude-fable-5:batchOverview
Claude Fable 5 is designed for complex reasoning, software engineering and research with multiple sequential stages. Supports extended tool use and analysis of visual material.
- Accepted inputs
- Text
- Results
- Text
Available in Ailoot · inputs & methods
Ailoot Ultra · Batch POST /v1/batches
- Input types
text- Output types
text- Output format
- inline results[].response.body JSON
| Field | Type | Requirement | Values & limits | Default |
|---|---|---|---|---|
Fieldendpoint | Typestring | RequirementRequired | Values & limits /v1/chat/completions | Default— |
Fieldmodel | Typestring | RequirementRequired | Values & limits anthropic/claude-fable-5:batch | Default— |
Fieldrequests | Typebatch_item[] | RequirementRequired | Values & limits Minimum items: 1 | Default— |
Fieldrequests[].custom_id | Typestring | RequirementRequired | Values & limits | Default— |
Fieldrequests[].body.messages | Typemessage[] | RequirementRequired | Values & limits | Default— |
Fieldcompletion_window | Typestring | RequirementOptional | Values & limits 24h | Default— |
Fieldprovider | Typeobject|null | RequirementOptional | Values & limits | Default— |
Fieldrequests[].body.model | Typestring | RequirementOptional | Values & limits anthropic/claude-fable-5:batch, anthropic/claude-fable-5 | Default— |
Fieldprovider.only | Typestring[] | RequirementOptional | Values & limits anthropic | Default— |
Fieldprovider.allow_fallbacks | Typeboolean|null | RequirementOptional | Values & limits false, null | Default— |
Method parameters and lifecycle
| Parameter | Contract |
|---|---|
Parametercontent_type | Contractapplication/json |
Parameterrequired | Contractendpoint, model, requests |
Parametermaterial_types | Contracttext |
Parameterrepresentation | Contractinline requests[]; each item has custom_id and body |
Parameterrequest_endpoint_profile | Contract/v1/chat/completions |
Parameterfile_material | ContractCaller may read actual UTF-8 JSONL locally into requests[]. No upload purpose, input_file_id or file reference is used. Missing/empty customer material stops preparation before POST. |
Parameterserialization_order | Contractendpoint, model, provider (if supplied), completion_window (if supplied), requests last |
Parameteroptional_controls | Contractprovider.only, provider.allow_fallbacks, completion_window |
Parameterschema_scope | ContractText Chat Completions bodies in the documented inline Batch envelope. |
Lifecycle: asynchronous
GET /v1/batches/{operation_id} · actual original create response.id; same user/key/group
Pricing
Tariff references do not add request options. Supported parameters are listed for the selected method.
- Fast mode
- Not specified When fast mode is selected
- Flex mode
- Not specified When flex mode is selected
- Maximum reasoning effort
- Not specified When maximum reasoning effort uses the default adjustment
- Explicit cache pricing
- Enabled When explicit cache is requested
Ailoot rates
Prices by configuration
Match each charge to the conditions shown. Use one rate for each set of alternative configurations.
| Configuration | Rate schedule | Context tokens, more than | Context tokens, up to and including | Charge |
|---|---|---|---|---|
| ConfigurationBase token rates | Rate scheduleBase rate | Context tokens, more than— | Context tokens, up to and includingNo upper bound | Charge Input · Input tokens $0.01 / 1K tokens Output · Output tokens $0.05 / 1K tokens Input · Cache read $0.001 / 1K tokens Input · Cache write $0.0125 / 1K tokens Input · Cache write, 1 hour $0.02 / 1K tokens |
| ConfigurationRequest-length tier 1 | Rate schedule— | Context tokens, more than0 | Context tokens, up to and includingNo upper bound | Charge Input · Input tokens $0.01 / 1K tokens Output · Output tokens $0.05 / 1K tokens Input · Cache read $0.001 / 1K tokens Input · Cache write $0.0125 / 1K tokens Input · Cache write, 1 hour $0.02 / 1K tokens |
Ailoot reserves an estimated amount before a request. After the result, it settles the final charge from measured usage. Streaming settlement uses the final usage record. How reservation and settlement work →
Example requests
Ailoot Ultra · Batch
set -eu
: "${AILOOT_API_KEY:?Set your Ailoot API key}"
python3 - <<'PY_REQUEST'
import json
from pathlib import Path
body=json.loads('{"endpoint":"/v1/chat/completions","model":"anthropic/claude-fable-5:batch","requests":[{"custom_id":"req-0001","body":{"messages":[{"role":"user","content":"Hello!"}],"max_tokens":16}}]}')
Path("batch-request.json").write_text(json.dumps(body,ensure_ascii=False),encoding="utf-8")
PY_REQUEST
curl --fail-with-body --silent --show-error https://api.ailoot.ai/v1/batches \
-H "Authorization: Bearer $AILOOT_API_KEY" -H 'Content-Type: application/json' \
--data-binary @batch-request.json -D batch-response-headers.txt -o batch-create-response.json
import json, os
from pathlib import Path
from urllib.request import Request, urlopen
def prepare_requests(customer_path):
path = Path(customer_path)
if not path.is_file(): raise ValueError("Customer JSONL file is missing")
items = [json.loads(line) for line in path.read_text(encoding="utf-8").splitlines() if line.strip()]
if not items: raise ValueError("Customer JSONL contains no requests")
ids = set()
for item in items:
if set(item) != {"custom_id", "body"}: raise ValueError("Each item needs custom_id and body")
cid = item["custom_id"]
if not isinstance(cid, str) or not cid.strip() or cid in ids: raise ValueError("custom_id must be nonempty and unique")
ids.add(cid)
if not isinstance(item["body"], dict) or not item["body"].get("messages"): raise ValueError("Supply actual text messages")
supplied_model = item["body"].get("model")
if supplied_model is not None and supplied_model not in ['anthropic/claude-fable-5:batch', 'anthropic/claude-fable-5']: raise ValueError("body.model must be an exact documented caller or wire ID")
return {"endpoint":"/v1/chat/completions", "model":"anthropic/claude-fable-5:batch", "requests":items}
if __name__ == "__main__":
material = os.environ.get("AILOOT_BATCH_REQUESTS_JSONL", "")
if not material: raise SystemExit("Set AILOOT_BATCH_REQUESTS_JSONL to your actual customer file")
body = prepare_requests(material)
key = os.environ.get("AILOOT_API_KEY", "")
if not key: raise SystemExit("Set AILOOT_API_KEY")
request = Request("https://api.ailoot.ai/v1/batches", data=json.dumps(body, ensure_ascii=False).encode("utf-8"), headers={"Authorization":"Bearer " + key, "Content-Type":"application/json"}, method="POST")
with urlopen(request) as response:
raw = response.read()
Path("batch-create-response.json").write_bytes(raw)
print(raw.decode("utf-8"))
import json
from pathlib import Path
raw = Path("batch-status-response.json").read_bytes()
response = json.loads(raw)
if response.get("status") != "completed":
raise SystemExit("Keep the original operation; read its status without resubmitting")
results = response.get("results")
if not isinstance(results, list) or not results:
raise SystemExit("Preserve the original response; completed results are missing")
Path("batch-results.jsonl").write_text("".join(json.dumps(item, ensure_ascii=False) + "\n" for item in results), encoding="utf-8")
# Preserve batch-status-response.json with aggregate usage and every result/error.
Receive and save results
Ailoot Ultra · Batch
inline results[].response.body JSON
GET /v1/batches/{operation_id}
Check job status
set -eu
: "${AILOOT_API_KEY:?Set your Ailoot API key}"
BATCH_OPERATION_ID="$(python3 - <<'PY_ID'
import json
from pathlib import Path
from urllib.parse import quote
response = json.loads(Path("batch-create-response.json").read_text(encoding="utf-8"))
operation = response.get("id")
if not isinstance(operation, str) or not operation: raise SystemExit("No actual original operation ID; preserve the response and do not resubmit")
print(quote(operation, safe=""))
PY_ID
)"
curl --fail-with-body --silent --show-error "https://api.ailoot.ai/v1/batches/$BATCH_OPERATION_ID" \
-H "Authorization: Bearer $AILOOT_API_KEY" -o batch-status-response.json
Keep all completed results
Keep every complete returned response, file and content part.
Preserve the full original status JSON, every result/custom_id and complete response or error body. Save completed results[] as JSONL without filtering.
If the original response needs checking
Preserve the original operation ID. 503 result_pending_check has X-Should-Retry:false; never resubmit an unknown original batch.
Response fields
| Field | Type |
|---|---|
Fieldresults[].custom_id | Typestring |
Fieldresults[].response.body.choices[].message.content | Typestring|null |
Fieldresults[].error | Typeobject|null |
Fieldusage | Typeobject|null |
Fieldid | Typestring |
Fieldmodel | Typestring |
Fieldendpoint | Typestring |
Fieldstatus | Typestring |
Fieldrequest_counts | Typeobject |
Fieldresults[].id | Typestring |
Fieldresults[].response.status_code | Typeinteger |
Fieldresults[].response.request_id | Typestring |
Errors and next steps
| Response | Condition | Next step |
|---|---|---|
Response400 · invalid_request_error | ConditionInvalid documented inline envelope, duplicate keys, item identity, or configured model capabilities conflict. | Next stepCorrect the indicated fields before any new submission. |
Response401 · authentication_error | ConditionInvalid API key. | Next stepUse the authorized Ailoot key. |
Response403 · permission_error | ConditionBatch group unavailable. | Next stepCheck key/group entitlement. |
Response422 · invalid_request_error | ConditionBatch uses balance billing; subscription creation is rejected. | Next stepUse the authorized balance-billed group. |
Response422 · price_unavailable | ConditionBatch input cannot be quoted. | Next stepPreserve response; use documented family input. |
Response402 · billing_error | ConditionBatch reserve unavailable. | Next stepResolve admission before a new request. |
Response503 · price_unavailable | ConditionBatch method price/native rates unavailable. | Next stepPreserve response; do not substitute prices. |
Response503 · api_error | ConditionExact supplier route unavailable. | Next stepPreserve response for route repair. |
Response503 · result_pending_check | ConditionOriginal result requires checking; X-Should-Retry:false. | Next stepKeep original operation_id/id and read its status; never repeat original POST. |
Response404 · not_found | ConditionBatch status operation absent or owned by another identity. | Next stepUse exact original id and same user/key/group. |
Aliases
Model aliases
Ailoot Ultra anthropic/claude-fable-5:batch
Method path aliases
Use the method paths shown above.
Related caller IDs
FAQ · Anthropic: Claude Fable 5 (batch)
- What inputs and results are available?
POST /v1/batches·anthropic/claude-fable-5:batch:text→text- Which fields does the request use?
POST /v1/batches·anthropic/claude-fable-5:batch:endpoint,model,requests,completion_window,provider- What limits apply?
POST /v1/batches·anthropic/claude-fable-5:batch:requests.min_items:1