For models that support it, the Anannas API can return Reasoning Tokens, also known as thinking tokens. Anannas normalizes the different ways of customizing the amount of reasoning tokens that the model will use, providing a unified interface across different providers.Reasoning tokens provide a transparent look into the reasoning steps taken by a model. Reasoning tokens are considered output tokens and charged accordingly.Reasoning tokens are included in the response by default if the model decides to output them. Reasoning tokens will appear in the reasoning field of each message, unless you decide to exclude them.
Some reasoning models do not return their reasoning tokensWhile most models and providers make reasoning tokens available in the response, some (like the OpenAI o-series and Gemini Flash Thinking) do not.
You can control reasoning tokens in your requests using the reasoning parameter:
{ "model": "your-model", "messages": [], "reasoning": { // One of the following (not both): "effort": "high", // Can be "high", "medium", or "low" (OpenAI-style) "max_tokens": 2000, // Specific token limit (Anthropic-style) // Optional: Default is false. All models support this. "exclude": false, // Set to true to exclude reasoning tokens from response // Or enable reasoning with the default parameters: "enabled": true // Default: inferred from `effort` or `max_tokens` }}
The reasoning config object consolidates settings for controlling reasoning strength across different models. See the Note for each option below to see which models are supported and how other models will behave.
For models that support max_tokens reasoning configuration, visit anannas.ai/models to see model-specific support.
Currently supported by:
Gemini thinking models
Anthropic reasoning models (by using the reasoning.max_tokens parameter)
Some Alibaba Qwen thinking models (mapped to thinking_budget)
For Alibaba, support varies by model — please check the individual model descriptions to confirm whether reasoning.max_tokens (via thinking_budget) is available.
For models that support reasoning token allocation, you can control it like this:
"max_tokens": 2000 - Directly specifies the maximum number of tokens to use for reasoning
For models that only support reasoning.effort (see below), the max_tokens value will be used to determine the effort level.
If you want the model to use reasoning internally but not include it in the response:
import requestsimport jsonurl = "https://api.anannas.ai/v1/chat/completions"headers = { "Authorization": f"Bearer <ANANNAS_API_KEY>", "Content-Type": "application/json"}payload = { "model": "deepseek/deepseek-r1", "messages": [ {"role": "user", "content": "Explain quantum computing in simple terms."} ], "reasoning": { "effort": "high", "exclude": true # Use reasoning but don't include it in the response }}response = requests.post(url, headers=headers, data=json.dumps(payload))# No reasoning field in the responseprint(response.json()['choices'][0]['message']['content'])
import OpenAI from 'openai';const openai = new OpenAI({ baseURL: 'https://api.anannas.ai/v1', apiKey: '<ANANNAS_API_KEY>',});async function getResponseWithReasoning() { const response = await openai.chat.completions.create({ model: 'deepseek/deepseek-r1', messages: [ { role: 'user', content: "How would you build the world's tallest skyscraper?", }, ], reasoning: { effort: 'high', exclude: true, // Use reasoning but don't include it in the response }, }); console.log('REASONING:', response.choices[0].message.reasoning); console.log('CONTENT:', response.choices[0].message.content);}getResponseWithReasoning();
This example shows how to use reasoning tokens in a more complex workflow. It injects one model’s reasoning into another model to improve its response quality:
import requestsimport jsonquestion = "Which is bigger: 9.11 or 9.9?"url = "https://api.anannas.ai/v1/chat/completions"headers = { "Authorization": f"Bearer <ANANNAS_API_KEY>", "Content-Type": "application/json"}def do_req(model, content, reasoning_config=None): payload = { "model": model, "messages": [ {"role": "user", "content": content} ], "stop": "</think>" } return requests.post(url, headers=headers, data=json.dumps(payload))# Get reasoning from a capable modelcontent = f"{question} Please think this through, but don't output an answer"reasoning_response = do_req("deepseek/deepseek-r1", content)reasoning = reasoning_response.json()['choices'][0]['message']['reasoning']# Let's test! Here's the naive response:simple_response = do_req("openai/gpt-5-mini", question)print(simple_response.json()['choices'][0]['message']['content'])# Here's the response with the reasoning token injected:content = f"{question}. Here is some context to help you: {reasoning}"smart_response = do_req("openai/gpt-5-mini", content)print(smart_response.json()['choices'][0]['message']['content'])
import OpenAI from 'openai';const openai = new OpenAI({ baseURL: 'https://api.anannas.ai/v1', apiKey,});async function doReq(model, content, reasoningConfig) { const payload = { model, messages: [{ role: 'user', content }], stop: '</think>', ...reasoningConfig, }; return openai.chat.completions.create(payload);}async function getResponseWithReasoning() { const question = 'Which is bigger: 9.11 or 9.9?'; const reasoningResponse = await doReq( 'deepseek/deepseek-r1', `${question} Please think this through, but don't output an answer`, ); const reasoning = reasoningResponse.choices[0].message.reasoning; // Let's test! Here's the naive response: const simpleResponse = await doReq('openai/gpt-5-mini', question); console.log(simpleResponse.choices[0].message.content); // Here's the response with the reasoning token injected: const content = `${question}. Here is some context to help you: ${reasoning}`; const smartResponse = await doReq('openai/gpt-5-mini', content); console.log(smartResponse.choices[0].message.content);}getResponseWithReasoning();
The latest Claude models, such as anthropic/claude-3.7-sonnet, support working with and returning reasoning tokens.You can enable reasoning on Anthropic models only using the unified reasoningparameter with either effort or max_tokens.Note: The :thinking variant is no longer supported for Anthropic models. Use the reasoning parameter instead.
For model-specific reasoning token limits and allocation rules, visit anannas.ai/models.
When using Anthropic models with reasoning:
When using the reasoning.max_tokens parameter, that value is used directly with a minimum of 1024 tokens.
When using the reasoning.effort parameter, the budget_tokens are calculated based on the max_tokens value.
The reasoning token allocation is capped at 32,000 tokens maximum and 1024 tokens minimum. The formula for calculating the budget_tokens is: budget_tokens = max(min(max_tokens * {effort_ratio}, 32000), 1024)effort_ratio is 0.8 for high effort, 0.5 for medium effort, and 0.2 for low effort.Important:
When using reasoning without tools, max_tokens must be strictly higher than the reasoning budget to ensure there are tokens available for the final response after thinking.
When using reasoning with tools (interleaved thinking), the budget_tokens can exceed max_tokens as it represents the total budget across all thinking blocks within one assistant turn.
Restrictions when reasoning is enabled:
tool_choice can only be "auto" or "none" (not "required" or specific tool)
top_k parameter is not allowed
Pre-filled assistant messages (assistant messages with content) are not allowed
Token Usage and BillingPlease note that reasoning tokens are counted as output tokens for billing purposes. Using reasoning tokens will increase your token usage but can significantly improve the quality of model responses.
Interleaved thinking is automatically enabled for Claude 4 models (Sonnet 4.5, Opus 4.5, Haiku 4.5) when reasoning is enabled with tools. Visit anannas.ai/models to see which models support this feature.
Interleaved thinking allows the model to reason between tool calls, enabling more sophisticated reasoning after receiving tool results. This feature is automatically enabled when:
Reasoning/thinking is enabled (reasoning.max_tokens or reasoning.effort)
Tools are present in the request
Tool choice is "auto" (or not specified, which defaults to auto)
Key Benefits:
Reasoning between tool calls: The model can think about tool results before deciding what to do next
Chained tool calls: Enables more nuanced decisions based on intermediate results
Flexible token allocation: With interleaved thinking, budget_tokens can exceed max_tokens as it represents the total budget across all thinking blocks
Example: Interleaved Thinking with Tools
from openai import OpenAIclient = OpenAI( base_url="https://api.anannas.ai/v1", api_key="<ANANNAS_API_KEY>",)response = client.chat.completions.create( model="anthropic/claude-sonnet-4-5-20250929", messages=[ { "role": "user", "content": "What's the weather in Paris? Also tell me the current time there." } ], tools=[ { "type": "function", "function": { "name": "get_weather", "description": "Get weather for a location", "parameters": { "type": "object", "properties": { "location": {"type": "string"} }, "required": ["location"] } } }, { "type": "function", "function": { "name": "get_time", "description": "Get current time for a location", "parameters": { "type": "object", "properties": { "location": {"type": "string"} }, "required": ["location"] } } } ], tool_choice="auto", # Required for interleaved thinking reasoning={ "max_tokens": 5000 # Can exceed max_tokens when interleaved thinking is enabled }, max_tokens=2000)# The model will reason before each tool call and after receiving resultsprint(response.choices[0].message.reasoning)print(response.choices[0].message.tool_calls)
import OpenAI from 'openai';const client = new OpenAI({ baseURL: 'https://api.anannas.ai/v1', apiKey: '<ANANNAS_API_KEY>',});const response = await client.chat.completions.create({ model: 'anthropic/claude-sonnet-4-5-20250929', messages: [ { role: 'user', content: "What's the weather in Paris? Also tell me the current time there.", }, ], tools: [ { type: 'function', function: { name: 'get_weather', description: 'Get weather for a location', parameters: { type: 'object', properties: { location: { type: 'string' }, }, required: ['location'], }, }, }, { type: 'function', function: { name: 'get_time', description: 'Get current time for a location', parameters: { type: 'object', properties: { location: { type: 'string' }, }, required: ['location'], }, }, }, ], tool_choice: 'auto', // Required for interleaved thinking reasoning: { max_tokens: 5000, // Can exceed max_tokens when interleaved thinking is enabled }, max_tokens: 2000,});// The model will reason before each tool call and after receiving resultsconsole.log(response.choices[0].message.reasoning);console.log(response.choices[0].message.tool_calls);
Tool Choice Restrictions with ThinkingWhen reasoning is enabled, only tool_choice: "auto" or tool_choice: "none" are supported. Using tool_choice: "required" or forcing a specific tool will result in an error.
Model SupportThe reasoning_details are currently returned by all OpenAI reasoning models (o1 series, o3 series, GPT-5 series) and all Anthropic reasoning models (Claude 3.7, Claude 4, and Claude 4.1 series).
The reasoning_details functionality works identically across all supported reasoning models. You can easily switch between OpenAI reasoning models (like openai/gpt-5-mini) and Anthropic reasoning models (like anthropic/claude-sonnet-4) without changing your code structure.If you want to pass reasoning back in context, you must pass reasoning blocks back to the API. This is useful for maintaining the model’s reasoning flow and conversation integrity.Preserving reasoning blocks is useful specifically for tool calling. When models like Claude invoke tools, it is pausing its construction of a response to await external information. When tool results are returned, the model will continue building that existing response. This necessitates preserving reasoning blocks during tool use, for a couple of reasons:Reasoning continuity: The reasoning blocks capture the model’s step-by-step reasoning that led to tool requests. When you post tool results, including the original reasoning ensures the model can continue its reasoning from where it left off.Context maintenance: While tool results appear as user messages in the API structure, they’re part of a continuous reasoning flow. Preserving reasoning blocks maintains this conceptual flow across multiple API calls.
Important for Reasoning ModelsWhen providing reasoning_details blocks, the entire sequence of consecutive reasoning blocks must match the outputs generated by the model during the original request; you cannot rearrange or modify the sequence of these blocks.
When reasoning models generate responses, the reasoning information is structured in a standardized format through the reasoning_details array. This section documents the API response structure for reasoning details in both streaming and non-streaming responses, based on the schema definitions in the llm-interfaces package.
The reasoning_details field contains an array of reasoning detail objects. Each object in the array represents a specific piece of reasoning information and follows one of three possible types. The location of this array differs between streaming and non-streaming responses:
Non-streaming responses: reasoning_details appears in choices[].message.reasoning_details
Streaming responses: reasoning_details appears in choices[].delta.reasoning_details for each chunk
1. Summary Type (reasoning.summary)Contains a high-level summary of the reasoning process:
{ "type": "reasoning.summary", "summary": "The model analyzed the problem by first identifying key constraints, then evaluating possible solutions...", "id": "reasoning-summary-1", "format": "anthropic-claude-v1", "index": 0}
2. Encrypted Type (reasoning.encrypted)Contains encrypted reasoning data that may be redacted or protected:
3. Text Type (reasoning.text)Contains raw text reasoning with optional signature verification:
{ "type": "reasoning.text", "text": "Let me think through this step by step:\n1. First, I need to understand the user's question...", "signature": "sha256:abc123def456...", "id": "reasoning-text-1", "format": "anthropic-claude-v1", "index": 2}
In non-streaming responses, reasoning_details appears in the message:
// add code here{ "choices": [ { "message": { "role": "assistant", "content": "Based on my analysis, I recommend the following approach...", "reasoning_details": [ { "type": "reasoning.summary", "summary": "Analyzed the problem by breaking it into components", "id": "reasoning-summary-1", "format": "anthropic-claude-v1", "index": 0 }, { "type": "reasoning.text", "text": "Let me work through this systematically:\n1. First consideration...\n2. Second consideration...", "signature": null, "id": "reasoning-text-1", "format": "anthropic-claude-v1", "index": 1 } ] } } ]}
Example: Preserving Reasoning Blocks with Anannas AI and Claude
from openai import OpenAIclient = OpenAI( base_url="https://api.anannas.ai/v1", api_key="<ANANNAS_API_KEY>",)# First API call with tools# Note: You can use 'openai/gpt-5-mini' instead of 'anthropic/claude-sonnet-4' - they're completely interchangeableresponse = client.chat.completions.create( model="anthropic/claude-sonnet-4", messages=[ {"role": "user", "content": "What's the weather like in Boston? Then recommend what to wear."} ], tools=[{ "type": "function", "function": { "name": "get_weather", "description": "Get current weather", "parameters": { "type": "object", "properties": { "location": {"type": "string"} }, "required": ["location"] } } }], reasoning={"max_tokens": 2000})# Extract the assistant message with reasoning_detailsmessage = response.choices[0].message# Preserve the complete reasoning_details when passing backmessages = [ {"role": "user", "content": "What's the weather like in Boston? Then recommend what to wear."}, { "role": "assistant", "content": message.content, "tool_calls": message.tool_calls, "reasoning_details": message.reasoning_details # Pass back unmodified }, { "role": "tool", "tool_call_id": message.tool_calls[0].id, "content": '{"temperature": 45, "condition": "rainy", "humidity": 85}' }]# Second API call - Claude continues reasoning from where it left offresponse2 = client.chat.completions.create( model="anthropic/claude-sonnet-4", messages=messages, # Includes preserved thinking blocks tools=tools)
import OpenAI from 'openai';const client = new OpenAI({ baseURL: 'https://api.anannas.ai/v1', apiKey: '<ANANNAS_API_KEY>',});// First API call with tools// Note: You can use 'openai/gpt-5-mini' instead of 'anthropic/claude-sonnet-4' - they're completely interchangeableconst response = await client.chat.completions.create({ model: 'anthropic/claude-sonnet-4', messages: [ { role: 'user', content: "What's the weather like in Boston? Then recommend what to wear.", }, ], tools: [ { type: 'function', function: { name: 'get_weather', description: 'Get current weather', parameters: { type: 'object', properties: { location: { type: 'string' }, }, required: ['location'], }, }, }, ], reasoning: { max_tokens: 2000 },});// Extract the assistant message with reasoning_detailsconst message = response.choices[0].message;// Preserve the complete reasoning_details when passing backconst messages = [ { role: 'user', content: "What's the weather like in Boston? Then recommend what to wear.", }, { role: 'assistant', content: message.content, tool_calls: message.tool_calls, reasoning_details: message.reasoning_details, // Pass back unmodified }, { role: 'tool', tool_call_id: message.tool_calls[0].id, content: JSON.stringify({ temperature: 45, condition: 'rainy', humidity: 85, }), },];// Second API call - Claude continues reasoning from where it left offconst response2 = await client.chat.completions.create({ model: 'anthropic/claude-sonnet-4', messages, // Includes preserved thinking blocks tools,});