Source: https://ailoot.ai/models/en/anthropic-claude-sonnet-4-5/
Canonical: https://ailoot.ai/models/en/anthropic-claude-sonnet-4-5/
Language: en

# Anthropic: Claude Sonnet 4.5

[Markdown](https://ailoot.ai/models/en/anthropic-claude-sonnet-4-5/index.md) · [JSON](https://ailoot.ai/models/en/anthropic-claude-sonnet-4-5/facts.json)

## [Anthropic: Claude Sonnet 4.5](https://ailoot.ai/models/en/anthropic-claude-sonnet-4-5/)

Claude Sonnet 4.5 is Anthropic’s text-and-image model for software development, complex agents, computer use and analytical work. It supports direct responses or manual extended thinking, with reasoning between tool calls in the documented beta workflow.

- [**Ailoot Ultra · OpenAI Chat** `POST /v1/chat/completions` `anthropic/claude-sonnet-4.5`](https://ailoot.ai/models/en/anthropic-claude-sonnet-4-5/#method-0)
- [**Ailoot Ultra · Anthropic Messages** `POST /v1/messages` `anthropic/claude-sonnet-4.5`](https://ailoot.ai/models/en/anthropic-claude-sonnet-4-5/#method-1)

About the model

This description covers the model’s capabilities. Available in Ailoot inputs, outputs and options are listed for the selected method below.

Claude Sonnet 4.5 is Anthropic’s Sonnet edition focused on software development, complex agent tasks and computer use, with improvements in reasoning and mathematics. It accepts text and images and generates text. The release describes sustained work across multiple steps, code comprehension and changes that involve a broader project rather than a single isolated function. A useful brief identifies the required behaviour, the relevant source material and the artifact to deliver: a proposed patch, an implementation explanation, a document analysis or a structured answer.

For software work, provide the project’s constraints, the relevant files or excerpts, the observed error and a concrete example of the expected result. Ask for the affected code and an explanation of how the proposed change addresses that example. The producer presents the model as suitable for building agents and working through development tasks with tools. The surrounding application reads and edits files, runs a command or check and returns its actual output; the model reasons over that evidence. Keep the proposed change and the completed check distinct in the final report.

Computer use is a separate application of its visual and agent capabilities. Anthropic’s release demonstrates browser interaction, navigating pages and working with spreadsheets through a connected environment. A visual brief can supply a screenshot, identify the goal and define which actions the application permits. The application then performs the selected interaction and returns the changed screen or other result. Similarly, the model can prepare content and code for documents, spreadsheets and slides, while the environment produces the finished file. Text-and-image understanding does not make the model a native image or audio generator.

The exact producer specification lists a 200K-token context window and up to 64K output tokens. Its reliable knowledge cutoff is January 2025, distinct from the later training-data cutoff listed on the page. Keep document boundaries, page labels, units and code identifiers clear in a long input, and reserve space for the requested answer and any reasoning. The producer also documents context awareness for this edition, so its supported workflow tracks the space remaining during a conversation. That helps manage a sustained task within its window; it does not replace the window with a later Sonnet edition’s larger capacity.

Sonnet 4.5 supports ordinary responses and manual extended thinking. In the latter mode, budget\_tokens sets a target for the internal reasoning before the visible answer. The documented minimum is 1,024 tokens, and the budget normally must be lower than max\_tokens because thinking and the final answer share the generation allowance. The budget is a target rather than a promise to consume exactly that many tokens. This edition does not have the adaptive-thinking mode or effort controls described for later Sonnet models. Choose the requested analysis depth and leave enough allowance for a usable final answer.

The producer’s interleaved-thinking beta lets Sonnet 4.5 reason between tool calls within a turn, using the returned observations to decide its next step. It requires the documented beta feature in the supported Messages workflow. In this case, the thinking budget can exceed max\_tokens because it spans multiple thinking blocks in the same assistant turn. Return tool results with the associated thinking content unmodified, including its signature; editing that content invalidates it. A research or debugging task can therefore alternate a proposed check, the real returned result and an updated analysis without treating a textual proposal as a completed action.

For visual material, the producer supports JPEG, PNG, GIF and WebP and uses only the first frame of an animation. The standard native image tier used by this edition has a 1,568-pixel long-edge limit and a 1,568-visual-token limit; larger images are downscaled. The producer’s image guide lists up to 100 images per API request for 200K-context models, with image and overall request-size conditions that can be reached first. Put images before the question when practical, label multiple images and preserve small text or chart labels. The guide recommends clear images and retaining enough surrounding context to interpret the visible detail.

Context editing and a memory tool were introduced alongside this model to support longer agent workflows. These are application-supported ways to retain useful state or remove old tool material; they are not an unlimited model memory or the later server-compaction feature. For a multi-stage task, preserve the decisions already made, the outstanding question and the evidence needed for the next step. Anthropic also describes stronger resistance to hidden instructions in external content, while noting that model-specific classifiers can sometimes flag benign material. The useful result remains a reviewable artifact tied to supplied evidence, with the exact Sonnet 4.5 modes and limits kept separate from later releases.

Practical task

### Repair an empty-cart total

Technical example in English

```
Repair an empty-cart total

Review this Python function: def total(items): return sum(x['price'] * x['qty'] for x in items) / len(items). It crashes for an empty cart and incorrectly averages nonempty carts. Return a minimal correction preserving the function signature, plus assertions for empty, one-line and two-line carts. Explain the changed behavior briefly.
```

#### Expected result

```
Corrected Python function, three concrete assertions and a brief explanation of sum versus average.
```

#### Check the result

```
The proposed tests cover empty input and verify that two cart lines are added rather than averaged.
```

**Ailoot Ultra · OpenAI Chat** `POST /v1/chat/completions` `anthropic/claude-sonnet-4.5`

[`anthropic/claude-sonnet-4.5`](https://ailoot.ai/models/en/#m=anthropic%2Fclaude-sonnet-4.5&route=Ultra&caller=anthropic%2Fclaude-sonnet-4.5&fmt=chat)

Anthropic /`anthropic/claude-sonnet-4.5`

### Overview

Claude Sonnet 4.5 is Anthropic’s text-and-image model for software development, complex agents, computer use and analytical work. It supports direct responses or manual extended thinking, with reasoning between tool calls in the documented beta workflow.

Accepted inputs

Text

Results

Text

### Available in Ailoot · inputs & methods

**Ailoot Ultra · OpenAI Chat** `POST /v1/chat/completions`

Input types

`text`

Output types

`text`

Output format

json or SSE

| Field | Type | Requirement | Values & limits | Default |
| --- | --- | --- | --- | --- |
| Field`model` | Type`string` | RequirementRequired | Values & limits anthropic/claude-sonnet-4.5 | Default— |
| Field`messages` | Type`message[]` | RequirementRequired | Values & limits Minimum items: 1 | Default— |
| Field`messages[].role` | Type`string` | RequirementRequired | Values & limits Examples: system, user, assistant, tool, function Conditions: These roles are explicitly represented by Source compatibility types; the exact model role set remains model-specific. Model-specific | Default— |
| Field`messages[].content` | Type`string\|content_part[]\|null` | RequirementOptional | Values & limits | Default— |
| Field`messages[].tool_calls` | Type`tool_call[]` | RequirementOptional | Values & limits | Default— |
| Field`messages[].tool_call_id` | Type`string` | RequirementOptional | Values & limits Applies when: role=tool; use actual returned ID | Default— |
| Field`messages[].name` | Type`string` | RequirementOptional | Values & limits | Default— |
| Field`messages[].reasoning_content` | Type`string` | RequirementOptional | Values & limits Applies when: Round-trip actual returned reasoning where this model uses it | Default— |
| Field`messages[].reasoning_details` | Type`object\|array` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`max_tokens` | Type`integer` | RequirementOptional | Values & limits Minimum: 1 Model-specific | Default— |
| Field`max_completion_tokens` | Type`integer` | RequirementOptional | Values & limits Minimum: 1 Model-specific | Default— |
| Field`stream` | Type`boolean` | RequirementOptional | Values & limits | Defaultfalse |
| Field`stream_options.include_usage` | Type`boolean` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`temperature` | Type`number` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`top_p` | Type`number` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`stop` | Type`string\|string[]` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`tools` | Type`function_tool[]` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`tools[].type` | Type`string` | RequirementOptional | Values & limits function Model-specific | Default— |
| Field`tools[].function.name` | Type`string` | RequirementRequired | Values & limits Applies when: function tool supplied | Default— |
| Field`tools[].function.description` | Type`string` | RequirementOptional | Values & limits | Default— |
| Field`tools[].function.parameters` | Type`JSON_schema` | RequirementOptional | Values & limits | Default— |
| Field`tool_choice` | Type`string\|object` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`parallel_tool_calls` | Type`boolean` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`response_format` | Type`object` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`reasoning_effort` | Type`string` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`reasoning` | Type`object` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`service_tier` | Type`string` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`instructions` | Type`string` | RequirementOptional | Values & limits Compatibility field | Default— |
| Field`functions` | Type`function[]` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`function_call` | Type`string\|object` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`prompt_cache_options` | Type`object` | RequirementOptional | Values & limits Model-specific | Default— |
| Field`modalities` | Type`string[]` | RequirementOptional | Values & limits text | Default— |
| Field`provider` | Type`object` | RequirementOptional | Values & limits Conditions: provider.options is rejected on this Ultra text route | Default— |
| Field`cache_control.ttl` | Type`string` | RequirementOptional | Values & limits Conditions: 1h is rejected in actual prompt-cache locations | Default— |

Input material combinations

**Text** · UTF8 text

`messages[].content`

Method parameters and lifecycle

| Parameter | Contract |
| --- | --- |
| Parameter`content_type` | Contractapplication/json |
| Parameter`required` | Contractmodel, messages |
| Parameter`material_types` | Contracttext |
| Parameter`messages` | Contractmessage array with role/content shape |
| Parameter`file_material` | Contractactual UTF-8 document inserted as literal text; no file ID inferred |
| Parameter`optional_controls` | Contractstream, temperature, top\_p, stop, max\_tokens, max\_completion\_tokens, reasoning, response\_format, tools, tool\_choice |
| Parameter`control_scope` | Contractmodel-specific; user function tools differ from hosted tools |
| Parameter`output_modalities` | Contracttext |
| Parameter`hosted_operations` | Contractfalse |
| Parameter`multimodal_input_binding` | Contractnull |

Lifecycle: `synchronous_or_streamed`

Send exact model ID with messages.

Context length is not an output cap.

A text file may supply literal text; image/audio/file-object inputs need exact binding.

### Pricing

Tariff references do not add request options. Supported parameters are listed for the selected method.

Fast mode

Standard rate When fast mode is selected

Flex mode

Standard rate When flex mode is selected

Maximum reasoning effort

Standard rate When maximum reasoning effort uses the default adjustment

#### 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 **$0.0132** / 1K tokens Output · Output tokens **$0.03** / 1K tokens Input · Cache read **$0.0006** / 1K tokens Input · Cache write **$0.0075** / 1K tokens Input · Cache write, 1 hour **$0.012** / 1K tokens |
| ConfigurationRequest-length tier 1 | Rate schedule— | Context tokens, more than0 | Context tokens, up to and including200,000 | Charge Input · Input tokens **$0.0132** / 1K tokens Output · Output tokens **$0.03** / 1K tokens Input · Cache read **$0.0006** / 1K tokens Input · Cache write **$0.0075** / 1K tokens Input · Cache write, 1 hour **$0.012** / 1K tokens |
| ConfigurationRequest-length tier 2 | Rate schedule— | Context tokens, more than200,000 | Context tokens, up to and includingNo upper bound | Charge Input · Input tokens **$0.0132** / 1K tokens Output · Output tokens **$0.03** / 1K tokens Input · Cache read **$0.0006** / 1K tokens Input · Cache write **$0.0075** / 1K tokens Input · Cache write, 1 hour **$0.024** / 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 →](https://ailoot.ai/docs/en/billing/reserve/)

### Example requests

#### Ailoot Ultra · OpenAI Chat

curlPython SDKPython stream

```bash
set -eu
: "${AILOOT_API_KEY:?Set your Ailoot API key}"
python3 - <<'PY_REQUEST'
import json,os
from pathlib import Path
p=json.loads('{"model": "anthropic/claude-sonnet-4.5", "messages": [{"role": "user", "content": "Explain the difference between an observation and a hypothesis in three sentences."}]}')

Path("request.json").write_text(json.dumps(p,ensure_ascii=False))
PY_REQUEST
curl --fail-with-body --silent --show-error https://api.ailoot.ai/v1/chat/completions \
  -H "Authorization: Bearer $AILOOT_API_KEY" -H 'Content-Type: application/json' \
  --data-binary @request.json -D response-headers.txt -o result.json
python3 - <<'PY_RESULT'
import json
from pathlib import Path
r=json.loads(Path("result.json").read_text())
for x in r.get("choices",[]):
    if x.get("message",{}).get("content"): print(x["message"]["content"])
PY_RESULT
```

```python
from openai import OpenAI
import os

if not os.environ.get("AILOOT_API_KEY", "").strip(): raise SystemExit("Set AILOOT_API_KEY before making a request")
client=OpenAI(base_url="https://api.ailoot.ai/v1",api_key=os.environ["AILOOT_API_KEY"],max_retries=0)
result=client.chat.completions.create(model='anthropic/claude-sonnet-4.5',messages=[{"role":"user","content":"Explain observations and hypotheses in three sentences."}])
import base64, json
from pathlib import Path

def save_result(data, stem="result"):
    # Keep every field, including usage, IDs, reasoning and tool requests.
    Path(stem + ".json").write_text(json.dumps(data, ensure_ascii=False, indent=2), encoding="utf-8")
    print(json.dumps(data, ensure_ascii=False, indent=2))
    def save_blob(encoded, suffix, label):
        raw = base64.b64decode(encoded, altchars=b"-_", validate=True)
        ext = "png" if raw.startswith(b"\x89PNG\r\n\x1a\n") else "jpg" if raw.startswith(b"\xff\xd8") else "webp" if raw[:4] == b"RIFF" and raw[8:12] == b"WEBP" else suffix
        file = Path(stem + "-" + label + "." + ext)
        file.write_bytes(raw)
        print("Saved", file)
    for index, block in enumerate(data.get("content") or []):
        print("Content", index, json.dumps(block, ensure_ascii=False))
    for choice in data.get("choices") or []:
        print("Choice", choice.get("index"), json.dumps(choice.get("message", choice.get("delta", {})), ensure_ascii=False))
    for index, item in enumerate(data.get("output") or []):
        print("Output", index, json.dumps(item, ensure_ascii=False))
        if item.get("type") == "image_generation_call" and item.get("result"):
            save_blob(item["result"], item.get("output_format") or "bin", "output-" + str(index))
    for ci, candidate in enumerate(data.get("candidates") or []):
        for pi, part in enumerate((candidate.get("content") or {}).get("parts") or []):
            print("Candidate/part", ci, pi, json.dumps(part, ensure_ascii=False))
            blob = part.get("inlineData") or part.get("inline_data")
            if blob and blob.get("data"):
                mime = blob.get("mimeType") or blob.get("mime_type")
                suffix = {"image/png":"png", "image/jpeg":"jpg", "image/webp":"webp", "audio/wav":"wav", "audio/mpeg":"mp3", "video/mp4":"mp4"}.get(mime, "bin")
                save_blob(blob["data"], suffix, "candidate-" + str(ci) + "-part-" + str(pi))

save_result(result.to_dict(mode="json"))
```

```python
from openai import OpenAI
import os
from pathlib import Path

if not os.environ.get("AILOOT_API_KEY", "").strip(): raise SystemExit("Set AILOOT_API_KEY before making a request")
client=OpenAI(base_url="https://api.ailoot.ai/v1",api_key=os.environ["AILOOT_API_KEY"],max_retries=0)
import base64, json
from pathlib import Path

def save_result(data, stem="result"):
    # Keep every field, including usage, IDs, reasoning and tool requests.
    Path(stem + ".json").write_text(json.dumps(data, ensure_ascii=False, indent=2), encoding="utf-8")
    print(json.dumps(data, ensure_ascii=False, indent=2))
    def save_blob(encoded, suffix, label):
        raw = base64.b64decode(encoded, altchars=b"-_", validate=True)
        ext = "png" if raw.startswith(b"\x89PNG\r\n\x1a\n") else "jpg" if raw.startswith(b"\xff\xd8") else "webp" if raw[:4] == b"RIFF" and raw[8:12] == b"WEBP" else suffix
        file = Path(stem + "-" + label + "." + ext)
        file.write_bytes(raw)
        print("Saved", file)
    for index, block in enumerate(data.get("content") or []):
        print("Content", index, json.dumps(block, ensure_ascii=False))
    for choice in data.get("choices") or []:
        print("Choice", choice.get("index"), json.dumps(choice.get("message", choice.get("delta", {})), ensure_ascii=False))
    for index, item in enumerate(data.get("output") or []):
        print("Output", index, json.dumps(item, ensure_ascii=False))
        if item.get("type") == "image_generation_call" and item.get("result"):
            save_blob(item["result"], item.get("output_format") or "bin", "output-" + str(index))
    for ci, candidate in enumerate(data.get("candidates") or []):
        for pi, part in enumerate((candidate.get("content") or {}).get("parts") or []):
            print("Candidate/part", ci, pi, json.dumps(part, ensure_ascii=False))
            blob = part.get("inlineData") or part.get("inline_data")
            if blob and blob.get("data"):
                mime = blob.get("mimeType") or blob.get("mime_type")
                suffix = {"image/png":"png", "image/jpeg":"jpg", "image/webp":"webp", "audio/wav":"wav", "audio/mpeg":"mp3", "video/mp4":"mp4"}.get(mime, "bin")
                save_blob(blob["data"], suffix, "candidate-" + str(ci) + "-part-" + str(pi))

with client.chat.completions.stream(model='anthropic/claude-sonnet-4.5',messages=[{"role":"user","content":"Explain observations and hypotheses in three sentences."}]) as stream:
    with Path("stream-events.jsonl").open("w",encoding="utf-8") as log:
        for event in stream:
            payload=event.to_dict(mode="json")
            log.write(json.dumps(payload,ensure_ascii=False)+"\n"); log.flush()
            print(json.dumps(payload,ensure_ascii=False))
    final=stream.get_final_completion()
    save_result(final.to_dict(mode="json"),"stream-result")
```

### Receive and save results

#### Ailoot Ultra · OpenAI Chat

json or SSE

##### Keep all completed results

Keep every complete returned response, file and content part.

Keep every choice and its content/tool calls/reasoning. In SSE assemble deltas by choice/tool index, retain the final finish reason and usage.

##### If the original response needs checking

Keep request/response IDs and headers. No generic text job retrieval URL is supplied.

Response fields

| Field | Type |
| --- | --- |
| Field`choices[].index` | Typeinteger |
| Field`choices[].message.content` | Typestring\|null |
| Field`choices[].message.tool_calls` | Typetool\_call\[\] |
| Field`choices[].message.reasoning_content` | Typestring |
| Field`choices[].message.reasoning_details` | Typeobject\|array |
| Field`choices[].finish_reason` | Typestring\|null |
| Field`usage` | Typeobject |

Errors and next steps

| Response | Condition | Next step |
| --- | --- | --- |
| Response400 · `invalid_request_error` | ConditionInvalid required fields, material representation or parameter value | Next stepCorrect the indicated fields before a new creation request. |

### Aliases

#### Model aliases

**Ailoot Ultra** [`anthropic/claude-sonnet-4.5`](https://ailoot.ai/models/en/#m=anthropic%2Fclaude-sonnet-4.5&route=Ultra&caller=anthropic%2Fclaude-sonnet-4.5&fmt=chat)

#### Method path aliases

Use the method paths shown above.

#### Related caller IDs

[`anthropic/claude-sonnet-4.5`](https://ailoot.ai/models/en/#m=anthropic%2Fclaude-sonnet-4.5&route=Ultra&caller=anthropic%2Fclaude-sonnet-4.5&fmt=chat)

**Ailoot Ultra · Anthropic Messages** `POST /v1/messages` `anthropic/claude-sonnet-4.5`

[`anthropic/claude-sonnet-4.5`](https://ailoot.ai/models/en/#m=anthropic%2Fclaude-sonnet-4.5&route=Ultra&caller=anthropic%2Fclaude-sonnet-4.5&fmt=messages)

Anthropic /`anthropic/claude-sonnet-4.5`

### Overview

Claude Sonnet 4.5 is Anthropic’s text-and-image model for software development, complex agents, computer use and analytical work. It supports direct responses or manual extended thinking, with reasoning between tool calls in the documented beta workflow.

Accepted inputs

Text

Results

json · sse

### Available in Ailoot · inputs & methods

**Ailoot Ultra · Anthropic Messages** `POST /v1/messages`

Input types

`text`

Output types

`json`, `sse`

Output format

JSON or SSE

| Field | Type | Requirement | Values & limits | Default |
| --- | --- | --- | --- | --- |
| Field`model` | Type`string` | RequirementRequired | Values & limits anthropic/claude-sonnet-4.5 | Default— |
| Field`messages` | Type`message[]` | RequirementRequired | Values & limits | Default— |
| Field`messages[].role` | Type`string` | RequirementRequired | Values & limits user, assistant | Default— |
| Field`messages[].content` | Type`string` | RequirementRequired | Values & limits | Default— |
| Field`max_tokens` | Type`integer` | RequirementRequired | Values & limits | Default— |
| Field`stream` | Type`boolean` | RequirementOptional | Values & limits | Defaultfalse |

Input material combinations

**Text** · UTF-8 text

`messages[].content string`

Method parameters and lifecycle

| Parameter | Contract |
| --- | --- |
| Parameter`content_type` | Contractapplication/json |
| Parameter`required` | Contractmodel, messages, max\_tokens |
| Parameter`optional_controls` | Contractstream |
| Parameter`material_types` | Contracttext |
| Parameter`text_file_material` | ContractRead the actual UTF-8 document and put its text in the indicated input or message content string. |

Lifecycle: `synchronous_or_streamed`

### Pricing

Tariff references do not add request options. Supported parameters are listed for the selected method.

Fast mode

Standard rate When fast mode is selected

Flex mode

Standard rate When flex mode is selected

Maximum reasoning effort

Standard rate When maximum reasoning effort uses the default adjustment

#### 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 **$0.0132** / 1K tokens Output · Output tokens **$0.03** / 1K tokens Input · Cache read **$0.0006** / 1K tokens Input · Cache write **$0.0075** / 1K tokens Input · Cache write, 1 hour **$0.012** / 1K tokens |
| ConfigurationRequest-length tier 1 | Rate schedule— | Context tokens, more than0 | Context tokens, up to and including200,000 | Charge Input · Input tokens **$0.0132** / 1K tokens Output · Output tokens **$0.03** / 1K tokens Input · Cache read **$0.0006** / 1K tokens Input · Cache write **$0.0075** / 1K tokens Input · Cache write, 1 hour **$0.012** / 1K tokens |
| ConfigurationRequest-length tier 2 | Rate schedule— | Context tokens, more than200,000 | Context tokens, up to and includingNo upper bound | Charge Input · Input tokens **$0.0132** / 1K tokens Output · Output tokens **$0.03** / 1K tokens Input · Cache read **$0.0006** / 1K tokens Input · Cache write **$0.0075** / 1K tokens Input · Cache write, 1 hour **$0.024** / 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 →](https://ailoot.ai/docs/en/billing/reserve/)

### Example requests

#### Ailoot Ultra · Anthropic Messages

Complete minimal JSON bodycurl · use your UTF-8 documentPython · save the complete result

```json
{
  "model": "anthropic/claude-sonnet-4.5",
  "max_tokens": 128,
  "messages": [
    {
      "role": "user",
      "content": "Summarize the incident report."
    }
  ],
  "stream": false
}
```

```bash
set -eu
: "${AILOOT_API_KEY:?Set your Ailoot API key}"
: "${AILOOT_TEXT_FILE:?Set your actual UTF-8 document}"
export AILOOT_TEXT_FILE
python3 - <<'PY_REQUEST'
import json, os
from pathlib import Path

source_file = Path(os.environ['AILOOT_TEXT_FILE'])
if not source_file.is_file():
    raise SystemExit('Set AILOOT_TEXT_FILE to your actual UTF-8 document')
text = source_file.read_text(encoding='utf-8')
if not text.strip():
    raise SystemExit('Choose a document containing text')
payload = {'model': 'anthropic/claude-sonnet-4.5', 'max_tokens': 128, 'messages': [{'role': 'user', 'content': 'Summarize the incident report.'}]}
payload['messages'][0]['content'] = 'Summarize this material and quote supporting source passages.\n\n' + text
Path('request.json').write_text(json.dumps(payload, ensure_ascii=False), encoding='utf-8')
PY_REQUEST
curl --fail-with-body --silent --show-error https://api.ailoot.ai/v1/messages \
  -H "x-api-key: $AILOOT_API_KEY" -H 'anthropic-version: 2023-06-01' -H 'Content-Type: application/json' \
  --data-binary @request.json -D response-headers.txt -o result.json
python3 - <<'PY_RESULT'
import json
from pathlib import Path

result = json.loads(Path('result.json').read_text(encoding='utf-8'))
print(json.dumps(result, ensure_ascii=False, indent=2))
PY_RESULT
```

```python
import json, os
from pathlib import Path

source_file = Path(os.environ['AILOOT_TEXT_FILE'])
if not source_file.is_file():
    raise SystemExit('Set AILOOT_TEXT_FILE to your actual UTF-8 document')
text = source_file.read_text(encoding='utf-8')
if not text.strip():
    raise SystemExit('Choose a document containing text')
payload = {'model': 'anthropic/claude-sonnet-4.5', 'max_tokens': 128, 'messages': [{'role': 'user', 'content': 'Summarize the incident report.'}]}
payload['messages'][0]['content'] = 'Summarize this material and quote supporting source passages.\n\n' + text
from urllib.request import Request, urlopen
from urllib.error import HTTPError

api_key = os.environ['AILOOT_API_KEY']
if not api_key.strip():
    raise SystemExit('Set AILOOT_API_KEY before making a request')
headers = {'x-api-key': 'PLACEHOLDER_KEY', 'anthropic-version': '2023-06-01', 'Content-Type': 'application/json'}
headers['x-api-key'] = api_key
request = Request('https://api.ailoot.ai/v1/messages', data=json.dumps(payload, ensure_ascii=False).encode('utf-8'), headers=headers, method='POST')
try:
    with urlopen(request, timeout=120) as response:
        raw = response.read()
        Path('response-headers.txt').write_text(str(response.headers), encoding='utf-8')
except HTTPError as error:
    Path('result.json').write_bytes(error.read())
    Path('response-headers.txt').write_text(str(error.headers), encoding='utf-8')
    raise
Path('result.json').write_bytes(raw)
import json
from pathlib import Path

result = json.loads(Path('result.json').read_text(encoding='utf-8'))
print(json.dumps(result, ensure_ascii=False, indent=2))
```

### Receive and save results

#### Ailoot Ultra · Anthropic Messages

JSON or SSE

##### Keep all completed results

Keep every complete returned response, file and content part.

Keep all content blocks, thinking signatures and actual tool-use IDs. Assemble all SSE block deltas; a first text block is not the complete output.

##### If the original response needs checking

Keep request/response IDs and headers. No generic text job retrieval URL is supplied.

Response fields

| Field | Type |
| --- | --- |
| Field`id` | Typestring |
| Field`model` | Typestring |
| Field`content[]` | Typetext\|thinking\|tool\_use\|other content block |
| Field`stop_reason` | Typestring\|null |
| Field`usage` | Typeobject |

Errors and next steps

| Response | Condition | Next step |
| --- | --- | --- |
| Response400 · `invalid_request_error` | ConditionInvalid required fields, material representation or parameter value | Next stepCorrect the indicated fields before a new creation request. |

### Aliases

#### Model aliases

**Ailoot Ultra** [`anthropic/claude-sonnet-4.5`](https://ailoot.ai/models/en/#m=anthropic%2Fclaude-sonnet-4.5&route=Ultra&caller=anthropic%2Fclaude-sonnet-4.5&fmt=messages)

#### Method path aliases

Use the method paths shown above.

#### Related caller IDs

[`anthropic/claude-sonnet-4.5`](https://ailoot.ai/models/en/#m=anthropic%2Fclaude-sonnet-4.5&route=Ultra&caller=anthropic%2Fclaude-sonnet-4.5&fmt=messages)

FAQ · Anthropic: Claude Sonnet 4.5

What inputs and results are available?

`POST /v1/chat/completions` · `anthropic/claude-sonnet-4.5`: `text` → `text` `POST /v1/messages` · `anthropic/claude-sonnet-4.5`: `text` → `json`, `sse`

Which fields does the request use?

`POST /v1/chat/completions` · `anthropic/claude-sonnet-4.5`: `model`, `messages`, `stream`, `modalities`, `provider` `POST /v1/messages` · `anthropic/claude-sonnet-4.5`: `model`, `messages`, `max_tokens`, `stream`

What limits apply?

`POST /v1/chat/completions` · `anthropic/claude-sonnet-4.5`: `messages.min_items`: `1`

Connect Ailoot to Claude Code, OpenCode, Hermes or your own app.

## The company and its project portfolio

The company and its project portfolio: millions of customers; monthly sales in the billions.

## Buy tokens at a discount.

Subscription discounts for regular use. Promo codes offer up to 50% off token purchases.

Subscription

Choose a discounted plan for your regular requests.

Promo code: up to 50% off

Enter your code at checkout. The price updates to reflect the current promotion.

Spending in your history

The model, tokens and amount are recorded for each request.

[Choose a subscription](https://ailoot.ai/docs/en/billing/subscriptions/) · [View model prices](https://ailoot.ai/models/en/)

## Connect the API to a product you sell.

Use Ailoot in SaaS, apps and bots under its official service offer and licence agreement. Request a reseller licence for resale.

Commercial application

Add text, image, video and audio generation to paid features in your service.

Reseller licence

Send a description of your project and how you provide access. Request written terms for use and resale.

Documents on the website

The service offer, licence agreement and data processing policy are available before you connect.

[Request a reseller licence](mailto:support@ailoot.ai) · [Service offer and licence agreement](https://ailoot.ai/legal/offer?lang=en)

## Ailoot · The company and its project portfolio





Ailoot combines established operating experience, a large client base, stable service and ongoing KPI control.





The company and its project portfolio: millions of customers; monthly sales in the billions.





Ailoot brings that operating experience to API access for AI features in customer products, agents, applications and automations.