Step 5 Preview is StepFun’s flagship foundation model for real-world agent tasks. The manufacturer describes a sparse mixture-of-experts architecture with 600 billion total parameters and 27B active parameters per token. It supports a 1M-token context and native text and visual input, with software engineering, professional knowledge work and finance as prominent task areas.
The edition is designed around work that extends beyond a single answer. A software assignment may require understanding the current implementation, planning a change, examining an observed failure and revising the proposed result. Prepare the expected behavior, the relevant source and the task’s constraints together, then request the artifact and the evidence needed to assess it.
For a code or application task, identify the component to change and what the completed behavior should look like. Visual input can add a screenshot, chart or other evidence relevant to that objective. Ask the result to distinguish what is visible in the material from a conclusion that depends on written specifications or observations from the application.
For professional research, state the question, the scope and the intended report structure. A useful output separates established findings, the reasoning connecting them and unresolved dependencies. If the application gathers additional information, return the relevant observations so the next step can use that evidence rather than assume it was found.
For financial analysis, provide the data, definitions, units and assumptions used in the task. Request a structured explanation of the calculation or comparison and identify which input supports each conclusion. The generated report or proposed analytical code can then be reviewed against those inputs. This is a preparation pattern for the producer’s stated domain, not a guarantee about a particular financial result.
For a continuing task, retain the source material, accepted findings and completion criteria with the next request. Keep it distinct from the earlier Step 3.7 Flash and from separately published weight or precision artifacts. The model’s output supplies text, code or analysis for a connected workflow; execution of proposed commands and changes to external systems is handled by the application and its tools.
", "aboutText": "Step 5 Preview is StepFun’s flagship foundation model for real-world agent tasks. The manufacturer describes a sparse mixture-of-experts architecture with 600 billion total parameters and 27B active parameters per token. It supports a 1M-token context and native text and visual input, with software engineering, professional knowledge work and finance as prominent task areas.\n\nThe edition is designed around work that extends beyond a single answer. A software assignment may require understanding the current implementation, planning a change, examining an observed failure and revising the proposed result. Prepare the expected behavior, the relevant source and the task’s constraints together, then request the artifact and the evidence needed to assess it.\n\nFor a code or application task, identify the component to change and what the completed behavior should look like. Visual input can add a screenshot, chart or other evidence relevant to that objective. Ask the result to distinguish what is visible in the material from a conclusion that depends on written specifications or observations from the application.\n\nFor professional research, state the question, the scope and the intended report structure. A useful output separates established findings, the reasoning connecting them and unresolved dependencies. If the application gathers additional information, return the relevant observations so the next step can use that evidence rather than assume it was found.\n\nFor financial analysis, provide the data, definitions, units and assumptions used in the task. Request a structured explanation of the calculation or comparison and identify which input supports each conclusion. The generated report or proposed analytical code can then be reviewed against those inputs. This is a preparation pattern for the producer’s stated domain, not a guarantee about a particular financial result.\n\nFor a continuing task, retain the source material, accepted findings and completion criteria with the next request. Keep it distinct from the earlier Step 3.7 Flash and from separately published weight or precision artifacts. The model’s output supplies text, code or analysis for a connected workflow; execution of proposed commands and changes to external systems is handled by the application and its tools.", "editorialOverlay": { "copy_fields": { "practical_html": "Technical example in English
Review a dependent approval workflow\n\nAnalyse this workflow against its requirement. Requirement R: a purchase order may be sent only after finance approval for the same revision. Current flow C: approval stores approved=true; editing quantities leaves approved unchanged; Send checks only that flag. Explain the defect, propose a revision-aware check and provide tests for unchanged and edited orders. Do not claim any purchase was sent.A source-linked defect analysis, a proposed revision-aware rule and two regression scenarios.Editing an approved order invalidates approval for the changed revision, while an unchanged approved revision remains eligible.stepfun/step-5-previewStepFun’s Step 5 Preview is a sparse MoE model for agentic coding, professional knowledge work and financial analysis. Its producer specifies 600B total parameters, 27B active per token, a 1M context and native text and visual input.
This description covers the model’s capabilities. Available in Ailoot inputs, outputs and options are listed for the selected method below.
Step 5 Preview is StepFun’s flagship foundation model for real-world agent tasks. The manufacturer describes a sparse mixture-of-experts architecture with 600 billion total parameters and 27B active parameters per token. It supports a 1M-token context and native text and visual input, with software engineering, professional knowledge work and finance as prominent task areas.
The edition is designed around work that extends beyond a single answer. A software assignment may require understanding the current implementation, planning a change, examining an observed failure and revising the proposed result. Prepare the expected behavior, the relevant source and the task’s constraints together, then request the artifact and the evidence needed to assess it.
For a code or application task, identify the component to change and what the completed behavior should look like. Visual input can add a screenshot, chart or other evidence relevant to that objective. Ask the result to distinguish what is visible in the material from a conclusion that depends on written specifications or observations from the application.
For professional research, state the question, the scope and the intended report structure. A useful output separates established findings, the reasoning connecting them and unresolved dependencies. If the application gathers additional information, return the relevant observations so the next step can use that evidence rather than assume it was found.
For financial analysis, provide the data, definitions, units and assumptions used in the task. Request a structured explanation of the calculation or comparison and identify which input supports each conclusion. The generated report or proposed analytical code can then be reviewed against those inputs. This is a preparation pattern for the producer’s stated domain, not a guarantee about a particular financial result.
For a continuing task, retain the source material, accepted findings and completion criteria with the next request. Keep it distinct from the earlier Step 3.7 Flash and from separately published weight or precision artifacts. The model’s output supplies text, code or analysis for a connected workflow; execution of proposed commands and changes to external systems is handled by the application and its tools.
POST /v1/chat/completionstexttext| Field | Type | Requirement | Values & limits | Default |
|---|---|---|---|---|
Fieldmodel | Typestring | RequirementRequired | Values & limits stepfun/step-5-preview | Default— |
Fieldmessages | Typemessage[] | RequirementRequired | Values & limits Minimum items: 1 | Default— |
Fieldmessages[].role | Typestring | 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— |
Fieldmessages[].content | Typestring|content_part[]|null | RequirementOptional | Values & limits | Default— |
Fieldmessages[].tool_calls | Typetool_call[] | RequirementOptional | Values & limits | Default— |
Fieldmessages[].tool_call_id | Typestring | RequirementOptional | Values & limits Applies when: role=tool; use actual returned ID | Default— |
Fieldmessages[].name | Typestring | RequirementOptional | Values & limits | Default— |
Fieldmessages[].reasoning_content | Typestring | RequirementOptional | Values & limits Applies when: Round-trip actual returned reasoning where this model uses it | Default— |
Fieldmessages[].reasoning_details | Typeobject|array | RequirementOptional | Values & limits Model-specific | Default— |
Fieldmax_tokens | Typeinteger | RequirementOptional | Values & limits Minimum: 1 Model-specific | Default— |
Fieldmax_completion_tokens | Typeinteger | RequirementOptional | Values & limits Minimum: 1 Model-specific | Default— |
Fieldstream | Typeboolean | RequirementOptional | Values & limits | Defaultfalse |
Fieldstream_options.include_usage | Typeboolean | RequirementOptional | Values & limits Model-specific | Default— |
Fieldtemperature | Typenumber | RequirementOptional | Values & limits Model-specific | Default— |
Fieldtop_p | Typenumber | RequirementOptional | Values & limits Model-specific | Default— |
Fieldstop | Typestring|string[] | RequirementOptional | Values & limits Model-specific | Default— |
Fieldtools | Typefunction_tool[] | RequirementOptional | Values & limits Model-specific | Default— |
Fieldtools[].type | Typestring | RequirementOptional | Values & limits function Model-specific | Default— |
Fieldtools[].function.name | Typestring | RequirementRequired | Values & limits Applies when: function tool supplied | Default— |
Fieldtools[].function.description | Typestring | RequirementOptional | Values & limits | Default— |
Fieldtools[].function.parameters | TypeJSON_schema | RequirementOptional | Values & limits | Default— |
Fieldtool_choice | Typestring|object | RequirementOptional | Values & limits Model-specific | Default— |
Fieldparallel_tool_calls | Typeboolean | RequirementOptional | Values & limits Model-specific | Default— |
Fieldresponse_format | Typeobject | RequirementOptional | Values & limits Model-specific | Default— |
Fieldreasoning_effort | Typestring | RequirementOptional | Values & limits Model-specific | Default— |
Fieldreasoning | Typeobject | RequirementOptional | Values & limits Model-specific | Default— |
Fieldservice_tier | Typestring | RequirementOptional | Values & limits Model-specific | Default— |
Fieldinstructions | Typestring | RequirementOptional | Values & limits Compatibility field | Default— |
Fieldfunctions | Typefunction[] | RequirementOptional | Values & limits Model-specific | Default— |
Fieldfunction_call | Typestring|object | RequirementOptional | Values & limits Model-specific | Default— |
Fieldprompt_cache_options | Typeobject | RequirementOptional | Values & limits Model-specific | Default— |
Fieldmodalities | Typestring[] | RequirementOptional | Values & limits text | Default— |
Fieldprovider | Typeobject | RequirementOptional | Values & limits Conditions: provider.options is rejected on this Ultra text route | Default— |
Fieldcache_control.ttl | Typestring | RequirementOptional | Values & limits Conditions: 1h is rejected in actual prompt-cache locations | Default— |
Text · UTF8 text
messages[].content
| Parameter | Contract |
|---|---|
Parametercontent_type | Contractapplication/json |
Parameterrequired | Contractmodel, messages |
Parametermaterial_types | Contracttext |
Parametermessages | Contractmessage array with role/content shape |
Parameterfile_material | Contractactual UTF-8 document inserted as literal text; no file ID inferred |
Parameteroptional_controls | Contractstream, temperature, top_p, stop, max_tokens, max_completion_tokens, reasoning, response_format, tools, tool_choice |
Parametercontrol_scope | Contractmodel-specific; user function tools differ from hosted tools |
Parameteroutput_modalities | Contracttext |
Parameterhosted_operations | Contractfalse |
Parametermultimodal_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.
Tariff references do not add request options. Supported parameters are listed for the selected method.
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 $0.002 / 1K tokens Output · Output tokens $0.0054 / 1K tokens Input · Cache read $0.0001 / 1K tokens Input · Cache write — / 1K tokens Input · Cache write, 1 hour — / 1K tokens |
| ConfigurationRequest-length tier 1 | Rate schedule— | Context tokens, more than0 | Context tokens, up to and includingNo upper bound | Charge Input · Input tokens $0.002 / 1K tokens Output · Output tokens $0.0054 / 1K tokens Input · Cache read $0.0001 / 1K tokens Input · Cache write — / 1K tokens Input · Cache write, 1 hour — / 1K tokens |
Ailoot reserves an estimated amount before a request. After the result, it settles the final charge from measured usage. Streaming settlement uses the final usage record. How reservation and settlement work →
set -eu\n: "${AILOOT_API_KEY:?Set your Ailoot API key}"\npython3 - <<'PY_REQUEST'\nimport json,os\nfrom pathlib import Path\np=json.loads('{"model": "stepfun/step-5-preview", "messages": [{"role": "user", "content": "Explain the difference between an observation and a hypothesis in three sentences."}]}')\n\nPath("request.json").write_text(json.dumps(p,ensure_ascii=False))\nPY_REQUEST\ncurl --fail-with-body --silent --show-error https://api.ailoot.ai/v1/chat/completions \\\n -H "Authorization: Bearer $AILOOT_API_KEY" -H 'Content-Type: application/json' \\\n --data-binary @request.json -D response-headers.txt -o result.json\npython3 - <<'PY_RESULT'\nimport json\nfrom pathlib import Path\nr=json.loads(Path("result.json").read_text())\nfor x in r.get("choices",[]):\n if x.get("message",{}).get("content"): print(x["message"]["content"])\nPY_RESULT\nfrom openai import OpenAI\nimport os\n\nif not os.environ.get("AILOOT_API_KEY", "").strip(): raise SystemExit("Set AILOOT_API_KEY before making a request")\nclient=OpenAI(base_url="https://api.ailoot.ai/v1",api_key=os.environ["AILOOT_API_KEY"],max_retries=0)\nresult=client.chat.completions.create(model='stepfun/step-5-preview',messages=[{"role":"user","content":"Explain observations and hypotheses in three sentences."}])\nimport base64, json\nfrom pathlib import Path\n\ndef save_result(data, stem="result"):\n # Keep every field, including usage, IDs, reasoning and tool requests.\n Path(stem + ".json").write_text(json.dumps(data, ensure_ascii=False, indent=2), encoding="utf-8")\n print(json.dumps(data, ensure_ascii=False, indent=2))\n def save_blob(encoded, suffix, label):\n raw = base64.b64decode(encoded, altchars=b"-_", validate=True)\n 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\n file = Path(stem + "-" + label + "." + ext)\n file.write_bytes(raw)\n print("Saved", file)\n for index, block in enumerate(data.get("content") or []):\n print("Content", index, json.dumps(block, ensure_ascii=False))\n for choice in data.get("choices") or []:\n print("Choice", choice.get("index"), json.dumps(choice.get("message", choice.get("delta", {})), ensure_ascii=False))\n for index, item in enumerate(data.get("output") or []):\n print("Output", index, json.dumps(item, ensure_ascii=False))\n if item.get("type") == "image_generation_call" and item.get("result"):\n save_blob(item["result"], item.get("output_format") or "bin", "output-" + str(index))\n for ci, candidate in enumerate(data.get("candidates") or []):\n for pi, part in enumerate((candidate.get("content") or {}).get("parts") or []):\n print("Candidate/part", ci, pi, json.dumps(part, ensure_ascii=False))\n blob = part.get("inlineData") or part.get("inline_data")\n if blob and blob.get("data"):\n mime = blob.get("mimeType") or blob.get("mime_type")\n suffix = {"image/png":"png", "image/jpeg":"jpg", "image/webp":"webp", "audio/wav":"wav", "audio/mpeg":"mp3", "video/mp4":"mp4"}.get(mime, "bin")\n save_blob(blob["data"], suffix, "candidate-" + str(ci) + "-part-" + str(pi))\n\nsave_result(result.to_dict(mode="json"))\nfrom openai import OpenAI\nimport os\nfrom pathlib import Path\n\nif not os.environ.get("AILOOT_API_KEY", "").strip(): raise SystemExit("Set AILOOT_API_KEY before making a request")\nclient=OpenAI(base_url="https://api.ailoot.ai/v1",api_key=os.environ["AILOOT_API_KEY"],max_retries=0)\nimport base64, json\nfrom pathlib import Path\n\ndef save_result(data, stem="result"):\n # Keep every field, including usage, IDs, reasoning and tool requests.\n Path(stem + ".json").write_text(json.dumps(data, ensure_ascii=False, indent=2), encoding="utf-8")\n print(json.dumps(data, ensure_ascii=False, indent=2))\n def save_blob(encoded, suffix, label):\n raw = base64.b64decode(encoded, altchars=b"-_", validate=True)\n 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\n file = Path(stem + "-" + label + "." + ext)\n file.write_bytes(raw)\n print("Saved", file)\n for index, block in enumerate(data.get("content") or []):\n print("Content", index, json.dumps(block, ensure_ascii=False))\n for choice in data.get("choices") or []:\n print("Choice", choice.get("index"), json.dumps(choice.get("message", choice.get("delta", {})), ensure_ascii=False))\n for index, item in enumerate(data.get("output") or []):\n print("Output", index, json.dumps(item, ensure_ascii=False))\n if item.get("type") == "image_generation_call" and item.get("result"):\n save_blob(item["result"], item.get("output_format") or "bin", "output-" + str(index))\n for ci, candidate in enumerate(data.get("candidates") or []):\n for pi, part in enumerate((candidate.get("content") or {}).get("parts") or []):\n print("Candidate/part", ci, pi, json.dumps(part, ensure_ascii=False))\n blob = part.get("inlineData") or part.get("inline_data")\n if blob and blob.get("data"):\n mime = blob.get("mimeType") or blob.get("mime_type")\n suffix = {"image/png":"png", "image/jpeg":"jpg", "image/webp":"webp", "audio/wav":"wav", "audio/mpeg":"mp3", "video/mp4":"mp4"}.get(mime, "bin")\n save_blob(blob["data"], suffix, "candidate-" + str(ci) + "-part-" + str(pi))\n\nwith client.chat.completions.stream(model='stepfun/step-5-preview',messages=[{"role":"user","content":"Explain observations and hypotheses in three sentences."}]) as stream:\n with Path("stream-events.jsonl").open("w",encoding="utf-8") as log:\n for event in stream:\n payload=event.to_dict(mode="json")\n log.write(json.dumps(payload,ensure_ascii=False)+"\\n"); log.flush()\n print(json.dumps(payload,ensure_ascii=False))\n final=stream.get_final_completion()\n save_result(final.to_dict(mode="json"),"stream-result")\njson or SSE
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.
Keep request/response IDs and headers. No generic text job retrieval URL is supplied.
| Field | Type |
|---|---|
Fieldchoices[].index | Typeinteger |
Fieldchoices[].message.content | Typestring|null |
Fieldchoices[].message.tool_calls | Typetool_call[] |
Fieldchoices[].message.reasoning_content | Typestring |
Fieldchoices[].message.reasoning_details | Typeobject|array |
Fieldchoices[].finish_reason | Typestring|null |
Fieldusage | Typeobject |
| 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. |
Ailoot Ultra stepfun/step-5-preview
Use the method paths shown above.
stepfun/step-5-previewStepFun’s Step 5 Preview is a sparse MoE model for agentic coding, professional knowledge work and financial analysis. Its producer specifies 600B total parameters, 27B active per token, a 1M context and native text and visual input.
This description covers the model’s capabilities. Available in Ailoot inputs, outputs and options are listed for the selected method below.
Step 5 Preview is StepFun’s flagship foundation model for real-world agent tasks. The manufacturer describes a sparse mixture-of-experts architecture with 600 billion total parameters and 27B active parameters per token. It supports a 1M-token context and native text and visual input, with software engineering, professional knowledge work and finance as prominent task areas.
The edition is designed around work that extends beyond a single answer. A software assignment may require understanding the current implementation, planning a change, examining an observed failure and revising the proposed result. Prepare the expected behavior, the relevant source and the task’s constraints together, then request the artifact and the evidence needed to assess it.
For a code or application task, identify the component to change and what the completed behavior should look like. Visual input can add a screenshot, chart or other evidence relevant to that objective. Ask the result to distinguish what is visible in the material from a conclusion that depends on written specifications or observations from the application.
For professional research, state the question, the scope and the intended report structure. A useful output separates established findings, the reasoning connecting them and unresolved dependencies. If the application gathers additional information, return the relevant observations so the next step can use that evidence rather than assume it was found.
For financial analysis, provide the data, definitions, units and assumptions used in the task. Request a structured explanation of the calculation or comparison and identify which input supports each conclusion. The generated report or proposed analytical code can then be reviewed against those inputs. This is a preparation pattern for the producer’s stated domain, not a guarantee about a particular financial result.
For a continuing task, retain the source material, accepted findings and completion criteria with the next request. Keep it distinct from the earlier Step 3.7 Flash and from separately published weight or precision artifacts. The model’s output supplies text, code or analysis for a connected workflow; execution of proposed commands and changes to external systems is handled by the application and its tools.
POST /v1/messagestextjson, sse| Field | Type | Requirement | Values & limits | Default |
|---|---|---|---|---|
Fieldmodel | Typestring | RequirementRequired | Values & limits stepfun/step-5-preview | Default— |
Fieldmessages | Typemessage[] | RequirementRequired | Values & limits | Default— |
Fieldmessages[].role | Typestring | RequirementRequired | Values & limits user, assistant | Default— |
Fieldmessages[].content | Typestring | RequirementRequired | Values & limits | Default— |
Fieldmax_tokens | Typeinteger | RequirementRequired | Values & limits | Default— |
Fieldstream | Typeboolean | RequirementOptional | Values & limits | Defaultfalse |
Text · UTF-8 text
messages[].content string
| Parameter | Contract |
|---|---|
Parametercontent_type | Contractapplication/json |
Parameterrequired | Contractmodel, messages, max_tokens |
Parameteroptional_controls | Contractstream |
Parametermaterial_types | Contracttext |
Parametertext_file_material | ContractRead the actual UTF-8 document and put its text in the indicated input or message content string. |
Lifecycle: synchronous_or_streamed
Tariff references do not add request options. Supported parameters are listed for the selected method.
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 $0.002 / 1K tokens Output · Output tokens $0.0054 / 1K tokens Input · Cache read $0.0001 / 1K tokens Input · Cache write — / 1K tokens Input · Cache write, 1 hour — / 1K tokens |
| ConfigurationRequest-length tier 1 | Rate schedule— | Context tokens, more than0 | Context tokens, up to and includingNo upper bound | Charge Input · Input tokens $0.002 / 1K tokens Output · Output tokens $0.0054 / 1K tokens Input · Cache read $0.0001 / 1K tokens Input · Cache write — / 1K tokens Input · Cache write, 1 hour — / 1K tokens |
Ailoot reserves an estimated amount before a request. After the result, it settles the final charge from measured usage. Streaming settlement uses the final usage record. How reservation and settlement work →
{\n "model": "stepfun/step-5-preview",\n "max_tokens": 128,\n "messages": [\n {\n "role": "user",\n "content": "Summarize the incident report."\n }\n ],\n "stream": false\n}set -eu\n: "${AILOOT_API_KEY:?Set your Ailoot API key}"\n: "${AILOOT_TEXT_FILE:?Set your actual UTF-8 document}"\nexport AILOOT_TEXT_FILE\npython3 - <<'PY_REQUEST'\nimport json, os\nfrom pathlib import Path\n\nsource_file = Path(os.environ['AILOOT_TEXT_FILE'])\nif not source_file.is_file():\n raise SystemExit('Set AILOOT_TEXT_FILE to your actual UTF-8 document')\ntext = source_file.read_text(encoding='utf-8')\nif not text.strip():\n raise SystemExit('Choose a document containing text')\npayload = {'model': 'stepfun/step-5-preview', 'max_tokens': 128, 'messages': [{'role': 'user', 'content': 'Summarize the incident report.'}]}\npayload['messages'][0]['content'] = 'Summarize this material and quote supporting source passages.\\n\\n' + text\nPath('request.json').write_text(json.dumps(payload, ensure_ascii=False), encoding='utf-8')\nPY_REQUEST\ncurl --fail-with-body --silent --show-error https://api.ailoot.ai/v1/messages \\\n -H "x-api-key: $AILOOT_API_KEY" -H 'anthropic-version: 2023-06-01' -H 'Content-Type: application/json' \\\n --data-binary @request.json -D response-headers.txt -o result.json\npython3 - <<'PY_RESULT'\nimport json\nfrom pathlib import Path\n\nresult = json.loads(Path('result.json').read_text(encoding='utf-8'))\nprint(json.dumps(result, ensure_ascii=False, indent=2))\nPY_RESULT\nimport json, os\nfrom pathlib import Path\n\nsource_file = Path(os.environ['AILOOT_TEXT_FILE'])\nif not source_file.is_file():\n raise SystemExit('Set AILOOT_TEXT_FILE to your actual UTF-8 document')\ntext = source_file.read_text(encoding='utf-8')\nif not text.strip():\n raise SystemExit('Choose a document containing text')\npayload = {'model': 'stepfun/step-5-preview', 'max_tokens': 128, 'messages': [{'role': 'user', 'content': 'Summarize the incident report.'}]}\npayload['messages'][0]['content'] = 'Summarize this material and quote supporting source passages.\\n\\n' + text\nfrom urllib.request import Request, urlopen\nfrom urllib.error import HTTPError\n\napi_key = os.environ['AILOOT_API_KEY']\nif not api_key.strip():\n raise SystemExit('Set AILOOT_API_KEY before making a request')\nheaders = {'x-api-key': 'PLACEHOLDER_KEY', 'anthropic-version': '2023-06-01', 'Content-Type': 'application/json'}\nheaders['x-api-key'] = api_key\nrequest = Request('https://api.ailoot.ai/v1/messages', data=json.dumps(payload, ensure_ascii=False).encode('utf-8'), headers=headers, method='POST')\ntry:\n with urlopen(request, timeout=120) as response:\n raw = response.read()\n Path('response-headers.txt').write_text(str(response.headers), encoding='utf-8')\nexcept HTTPError as error:\n Path('result.json').write_bytes(error.read())\n Path('response-headers.txt').write_text(str(error.headers), encoding='utf-8')\n raise\nPath('result.json').write_bytes(raw)\nimport json\nfrom pathlib import Path\n\nresult = json.loads(Path('result.json').read_text(encoding='utf-8'))\nprint(json.dumps(result, ensure_ascii=False, indent=2))\nJSON or SSE
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.
Keep request/response IDs and headers. No generic text job retrieval URL is supplied.
| Field | Type |
|---|---|
Fieldid | Typestring |
Fieldmodel | Typestring |
Fieldcontent[] | Typetext|thinking|tool_use|other content block |
Fieldstop_reason | Typestring|null |
Fieldusage | Typeobject |
| 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. |
Ailoot Ultra stepfun/step-5-preview
Use the method paths shown above.
Technical example in English
Review a dependent approval workflow\n\nAnalyse this workflow against its requirement. Requirement R: a purchase order may be sent only after finance approval for the same revision. Current flow C: approval stores approved=true; editing quantities leaves approved unchanged; Send checks only that flag. Explain the defect, propose a revision-aware check and provide tests for unchanged and edited orders. Do not claim any purchase was sent.A source-linked defect analysis, a proposed revision-aware rule and two regression scenarios.Editing an approved order invalidates approval for the changed revision, while an unchanged approved revision remains eligible.