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POST
/
v1
/
messages
claude-haiku-4-5-20251001 (Text To Text)
curl --request POST \
  --url https://gptproto.com/v1/messages

Documentation Index

Fetch the complete documentation index at: https://docs.gptproto.com/llms.txt

Use this file to discover all available pages before exploring further.

​
Authentication

  1. Sign up for a GPTProto account at https://gptproto.com
  2. Navigate to the API Keys section in your dashboard
  3. Generate a new API key (sk-xxxxx)
  4. Copy and securely store your API key For authentication details, please refer to the Authentication section.

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Initiate Request

curl --location 'https://gptproto.com/v1/messages' \
--header 'Authorization: GPTPROTO_API_KEY' \
--header 'Content-Type: application/json' \
--header 'anthropic-version: 2023-06-01' \
--data '{
  "model": "claude-haiku-4-5-20251001",
  "max_tokens": 1024,
  "messages": [
    {
      "role": "user",
      "content": "Who are you?"
    }
  ]
}'


{
    "id": "msg_abcd",
    "type": "message",
    "role": "assistant",
    "model": "<model>",
    "content": [
        {
            "type": "text",
            "text": "I'm Claude, an AI assistant made by Anthropic. I'm designed to be helpful, harmless, and honest. I can help with a wide range of tasks like answering questions, writing, analysis, brainstorming, coding, and more.\n\nIs there something I can help you with?"
        }
    ],
    "stop_reason": "end_turn",
    "usage": {
        "input_tokens": 11,
        "cache_creation_input_tokens": 0,
        "cache_read_input_tokens": 0,
        "output_tokens": 67,
        "cache_creation": {},
        "claude_cache_creation_5_m_tokens": 0,
        "claude_cache_creation_1_h_tokens": 0
    }
}

​
Parameters

ParameterTypeRequiredDefaultRangeDescription
modelstring✅ Yesclaude-opus-4-6-The model identifier. Use claude-opus-4-6 for this model
messagesarray✅ Yes--Input messages for the conversation. Each message must have a role (user/assistant) and content (string or array of content blocks)
max_tokensinteger✅ Yes-1-64000Maximum number of tokens to generate. The model may stop before reaching this limit
toolsarray✅ Yes--Array of tool objects. For web search, must include the web_search tool configuration with type web_search_20250305
temperaturenumber❌ No1.00.0-1.0Controls randomness in output. Use lower values (closer to 0.0) for analytical tasks, higher values (closer to 1.0) for creative tasks. Note: Even at 0.0, results are not fully deterministic
top_pnumber❌ No-0.0-1.0Nucleus sampling threshold. Controls diversity by considering only tokens with cumulative probability up to top_p. Recommended for advanced use only. Do not use with temperature
top_kinteger❌ No->0Only sample from the top K options for each token. Removes low probability responses. Recommended for advanced use only
streamboolean❌ Nofalse-Whether to stream the response incrementally using server-sent events
stop_sequencesarray❌ No-Max 8191 sequencesCustom text sequences that will cause the model to stop generating. Each sequence must contain non-whitespace characters

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Messages Array Structure

Each message object in the messages array should have the following structure:
FieldTypeRequiredRangeDescription
rolestring✅ Yes-The role of the message. Can be: user or assistant
contentstring/array✅ Yes-The content of the message. Can be a simple string for text-only messages, or an array of content blocks for multimodal content

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Content Block Structure (when content is an array)

FieldTypeRequiredRangeDescription
typestring✅ Yes-Must be text
textstring✅ Yes-The text content

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Tools Array Structure

For web search functionality, the tools array should contain a web search tool object:
FieldTypeRequiredRangeDescription
typestring✅ Yes-The type of tool. Must be web_search_20250305 for web search
namestring✅ Yes-The name of the tool. Use web_search
max_usesinteger❌ No1-10Maximum number of times the web search tool can be used in a single request
allowed_domainsarray❌ No-Only include search results from these domains. Cannot be used with blocked_domains
blocked_domainsarray❌ No-Never include search results from these domains. Cannot be used with allowed_domains
user_locationobject❌ No-Localize search results based on user’s location

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Max Uses

The max_uses parameter limits the number of searches performed. If Claude attempts more searches than allowed, the web_search_tool_result will be an error with the max_uses_exceeded error code.

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Domain Filtering

When using domain filters:
  • Domains should not include the HTTP/HTTPS scheme (use example.com instead of https://example.com)
  • Subdomains are automatically included (example.com covers docs.example.com)
  • Specific subdomains restrict results to only that subdomain (docs.example.com returns only results from that subdomain, not from example.com or api.example.com)
  • Subpaths are supported (example.com/blog)
  • You can use either allowed_domains or blocked_domains, but not both in the same request
  • Request-level domain restrictions must be compatible with organization-level domain restrictions configured in the Console

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User Location Structure

The user_location object allows you to localize search results based on a user’s location:
FieldTypeRequiredRangeDescription
typestring✅ Yes-The type of location. Must be approximate
citystring✅ Yes-The city name (e.g., San Francisco)
regionstring✅ Yes-The region or state (e.g., California)
countrystring✅ Yes-The country code (e.g., US)
timezonestring✅ Yes-The IANA timezone ID (e.g., America/Los_Angeles)

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Complete Tool Configuration Example

{
  "type": "web_search_20250305",
  "name": "web_search",
  "max_uses": 5,
  "allowed_domains": ["example.com", "trusteddomain.org"],
  "user_location": {
    "type": "approximate",
    "city": "San Francisco",
    "region": "California",
    "country": "US",
    "timezone": "America/Los_Angeles"
  }
}

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Error Codes

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Common Error Codes

Error CodeError NameDescription
401UnauthorizedAPI key is missing or invalid
403ForbiddenYour API key doesn’t have permission to access this resource, or insufficient balance for the requested operation
429Too Many RequestsYou’ve exceeded your rate limit
500Internal server errorAn internal server error occurred
503Content policy violationContent blocked due to safety concerns (actual status code is 400)