Beam 1.0 501B A23B

Text Generation • reflection-ai

reflection-ai/beam-1.0-501b-a23b

  • Third-party

Beam-1.0-501B-A23B is Reflection AI's open-weights mixture-of-experts model with 501B total parameters and 23B active parameters, built for coding, reasoning, and agentic workloads.

Model Info
Context Window ↗ 262,144 tokens
Terms and License link ↗
More information link ↗
Request formats Chat Completions
Pricing <ul><li>Input (per 1M tokens)$0.00</li><li>Cached input (per 1M tokens)$0.00</li><li>Output (per 1M tokens)$0.00</li></ul>

Usage

const response = await env.AI.run(
  'reflection-ai/beam-1.0-501b-a23b',
  {
    messages: [{ role: 'user', content: 'Explain why the sky is blue in one sentence.' }],
    max_completion_tokens: 256,
    reasoning_effort: 'low',
  },
)
console.log(response)

curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/v1/chat/completions \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "reflection-ai/beam-1.0-501b-a23b",
  "messages": [
    {
      "role": "user",
      "content": "Explain why the sky is blue in one sentence."
    }
  ],
  "max_completion_tokens": 256,
  "reasoning_effort": "low"
}'

The sky is blue because sunlight undergoes Rayleigh scattering in the atmosphere, which preferentially redirects shorter blue wavelengths toward your eyes.

{
  "id": "chatcmpl-002d24bd-de9c-4bab-947d-47f77166eb5c",
  "object": "chat.completion",
  "created": 1792089654,
  "model": "reflection-ai/beam-1.0-501b-a23b",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "The sky is blue because sunlight undergoes Rayleigh scattering in the atmosphere, which preferentially redirects shorter blue wavelengths toward your eyes.",
        "refusal": null,
        "reasoning_content": "The user asks: \"Explain why the sky is blue in one sentence.\" Straightforward. Need one sentence. Ensure accuracy: Rayleigh scattering scatters shorter blue wavelengths more. Provide concise. No safety issues."
      },
      "finish_reason": "stop",
      "logprobs": null
    }
  ],
  "usage": {
    "prompt_tokens": 506,
    "completion_tokens": 79,
    "total_tokens": 585,
    "prompt_tokens_details": {
      "cached_tokens": 448
    },
    "completion_tokens_details": {
      "reasoning_tokens": 50
    }
  }
}

Examples

<details>

<summary>Structured project status — Return a typed project status summary using structured output</summary>

const response = await env.AI.run(
  'reflection-ai/beam-1.0-501b-a23b',
  {
    messages: [
      {
        role: 'user',
        content:
          'Summarize this project update: API integration is complete, security review is scheduled for Friday, and the mobile client is blocked on final design assets.',
      },
    ],
    max_completion_tokens: 512,
    response_format: {
      type: 'json_schema',
      json_schema: {
        name: 'project_status',
        strict: true,
        schema: {
          type: 'object',
          properties: {
            overall_status: { type: 'string', enum: ['on_track', 'at_risk', 'blocked'] },
            completed: { type: 'array', items: { type: 'string' } },
            next_steps: { type: 'array', items: { type: 'string' } },
            blockers: { type: 'array', items: { type: 'string' } },
          },
          required: ['overall_status', 'completed', 'next_steps', 'blockers'],
          additionalProperties: false,
        },
      },
    },
  },
)
console.log(response)

curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/v1/chat/completions \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "reflection-ai/beam-1.0-501b-a23b",
  "messages": [
    {
      "role": "user",
      "content": "Summarize this project update: API integration is complete, security review is scheduled for Friday, and the mobile client is blocked on final design assets."
    }
  ],
  "max_completion_tokens": 512,
  "response_format": {
    "type": "json_schema",
    "json_schema": {
      "name": "project_status",
      "strict": true,
      "schema": {
        "type": "object",
        "properties": {
          "overall_status": {
            "type": "string",
            "enum": [
              "on_track",
              "at_risk",
              "blocked"
            ]
          },
          "completed": {
            "type": "array",
            "items": {
              "type": "string"
            }
          },
          "next_steps": {
            "type": "array",
            "items": {
              "type": "string"
            }
          },
          "blockers": {
            "type": "array",
            "items": {
              "type": "string"
            }
          }
        },
        "required": [
          "overall_status",
          "completed",
          "next_steps",
          "blockers"
        ],
        "additionalProperties": false
      }
    }
  }
}'

{"overall_status": "on_track",
"completed": ["API integration"],
"next_steps": ["Security review scheduled for Friday"],
"blockers": ["Mobile client awaiting final design assets"]}

{
  "id": "chatcmpl-781353f2-706b-4d56-b771-c785968bbf97",
  "object": "chat.completion",
  "created": 1792089661,
  "model": "reflection-ai/beam-1.0-501b-a23b",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "{\"overall_status\": \"on_track\",\n\"completed\": [\"API integration\"],\n\"next_steps\": [\"Security review scheduled for Friday\"],\n\"blockers\": [\"Mobile client awaiting final design assets\"]}",
        "refusal": null,
        "reasoning_content": "The user wants a summary of a project update. Straightforward. Just summarize."
      },
      "finish_reason": "stop",
      "logprobs": null
    }
  ],
  "usage": {
    "prompt_tokens": 527,
    "completion_tokens": 64,
    "total_tokens": 591,
    "prompt_tokens_details": {
      "cached_tokens": 512
    },
    "completion_tokens_details": {
      "reasoning_tokens": 18
    }
  }
}

</details>

<details>

<summary>Weather tool call — Choose a weather lookup function and supply its arguments</summary>

const response = await env.AI.run(
  'reflection-ai/beam-1.0-501b-a23b',
  {
    messages: [{ role: 'user', content: 'What is the weather in Lisbon today?' }],
    max_completion_tokens: 256,
    tool_choice: 'required',
    tools: [
      {
        type: 'function',
        function: {
          name: 'get_weather',
          description: 'Look up the current weather for a city.',
          parameters: {
            type: 'object',
            properties: {
              city: { type: 'string' },
              units: { type: 'string', enum: ['celsius', 'fahrenheit'] },
            },
            required: ['city', 'units'],
            additionalProperties: false,
          },
        },
      },
    ],
  },
)
console.log(response)

curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/v1/chat/completions \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "reflection-ai/beam-1.0-501b-a23b",
  "messages": [
    {
      "role": "user",
      "content": "What is the weather in Lisbon today?"
    }
  ],
  "max_completion_tokens": 256,
  "tool_choice": "required",
  "tools": [
    {
      "type": "function",
      "function": {
        "name": "get_weather",
        "description": "Look up the current weather for a city.",
        "parameters": {
          "type": "object",
          "properties": {
            "city": {
              "type": "string"
            },
            "units": {
              "type": "string",
              "enum": [
                "celsius",
                "fahrenheit"
              ]
            }
          },
          "required": [
            "city",
            "units"
          ],
          "additionalProperties": false
        }
      }
    }
  ]
}'

{
  "id": "chatcmpl-fda9d6ad-dcb0-4b60-9e5a-4d78f406ecc1",
  "object": "chat.completion",
  "created": 1792089672,
  "model": "reflection-ai/beam-1.0-501b-a23b",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": null,
        "tool_calls": [
          {
            "id": "call-c105de7f-4e34-4ce9-bab9-ef2e6a89b645",
            "type": "function",
            "function": {
              "name": "get_weather",
              "arguments": "{\"city\": \"Lisbon\", \"units\": \"celsius\"}"
            }
          }
        ],
        "refusal": null,
        "reasoning_content": "The user is asking about the weather in Lisbon today. I have a tool to get weather. Let me call it with city Lisbon and units... the user didn't specify units. Celsius is reasonable default, but maybe I should pick. Let me use celsius as default. Actually, let me just call."
      },
      "finish_reason": "tool_calls",
      "logprobs": null
    }
  ],
  "usage": {
    "prompt_tokens": 544,
    "completion_tokens": 92,
    "total_tokens": 636,
    "prompt_tokens_details": {
      "cached_tokens": 512
    },
    "completion_tokens_details": {
      "reasoning_tokens": 69
    }
  }
}

</details>

<details>

<summary>Scheduling reasoning — Reason through a scheduling constraint with system guidance</summary>

const response = await env.AI.run(
  'reflection-ai/beam-1.0-501b-a23b',
  {
    messages: [
      {
        role: 'system',
        content: 'Answer concisely and show the scheduling logic in two bullet points.',
      },
      {
        role: 'user',
        content:
          'Maya is available Monday and Wednesday. Theo is available Wednesday and Thursday. Priya is available Monday, Wednesday, and Friday. Which day should they schedule a 90-minute meeting, and why?',
      },
      { role: 'user', content: 'The meeting must include all three attendees.' },
      { role: 'user', content: 'Please give the recommendation.' },
    ],
    max_completion_tokens: 384,
    reasoning_effort: 'medium',
  },
)
console.log(response)

curl https://api.cloudflare.com/client/v4/accounts/$CLOUDFLARE_ACCOUNT_ID/ai/v1/chat/completions \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "reflection-ai/beam-1.0-501b-a23b",
  "messages": [
    {
      "role": "system",
      "content": "Answer concisely and show the scheduling logic in two bullet points."
    },
    {
      "role": "user",
      "content": "Maya is available Monday and Wednesday. Theo is available Wednesday and Thursday. Priya is available Monday, Wednesday, and Friday. Which day should they schedule a 90-minute meeting, and why?"
    },
    {
      "role": "user",
      "content": "The meeting must include all three attendees."
    },
    {
      "role": "user",
      "content": "Please give the recommendation."
    }
  ],
  "max_completion_tokens": 384,
  "reasoning_effort": "medium"
}'

- All three must attend, so the meeting day must be in the intersection of Maya's (Mon, Wed), Theo's (Wed, Thu), and Priya's (Mon, Wed, Fri) calendars; only Wednesday appears for all three.
- Therefore, schedule the 90-minute meeting on Wednesday, since it is the only day all attendees are available.

{
  "id": "chatcmpl-26cd51e7-33f7-4048-93f0-69f51b1c66cc",
  "object": "chat.completion",
  "created": 1792089681,
  "model": "reflection-ai/beam-1.0-501b-a23b",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "- All three must attend, so the meeting day must be in the intersection of Maya's (Mon, Wed), Theo's (Wed, Thu), and Priya's (Mon, Wed, Fri) calendars; only Wednesday appears for all three.\n- Therefore, schedule the 90-minute meeting on Wednesday, since it is the only day all attendees are available.",
        "refusal": null,
        "reasoning_content": "The user asks: Maya available Mon/Wed, Theo available Wed/Thu, Priya available Mon/Wed/Fri. Meeting must include all three. Need schedule 90-min meeting. Which day should schedule and why? Concise, two bullet points showing scheduling logic. Constraints: all three must attend. Intersection: Maya ∩ Theo = Wed; Priya ∩ {Wed} = Wed. So Wednesday is common day. Need 90-minute meeting—presumably available all day? No time specifics. So recommend Wednesday; only day all three available. Answer with two bullet points.\n\nNeed ensure not violate policy. Fine.\n\nLet's craft concise."
      },
      "finish_reason": "stop",
      "logprobs": null
    }
  ],
  "usage": {
    "prompt_tokens": 572,
    "completion_tokens": 218,
    "total_tokens": 790,
    "prompt_tokens_details": {
      "cached_tokens": 448
    },
    "completion_tokens_details": {
      "reasoning_tokens": 138
    }
  }
}

</details>

Parameters

▶messages[]

arrayrequired

temperature

numberminimum: 0maximum: 2

max_tokens

numberexclusiveMinimum: 0

max_completion_tokens

numberexclusiveMinimum: 0

top_p

numberminimum: 0maximum: 1

frequency_penalty

numberminimum: -2maximum: 2

presence_penalty

numberminimum: -2maximum: 2

stream

boolean

▶stream_options{}

object

▶tools[]

array

tool_choice

response_format

▶modalities[]

array

▶audio{}

object

reasoning_effort

stringOptional reasoning control; availability and accepted values are model-dependent.

id

string

object

string

created

number

model

string

▶choices[]

array

▶usage{}

object

API Schemas (Raw)

Input Open Download

Output Open Download

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