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Models

List the models Little Worker serves and read what each one can do and costs.

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A model is the AI that does a worker's thinking. A worker names one in its model, or leaves it out and follows its Quality: Fast, Standard or Best. Each Quality picks one model, and a read of the worker answers the model its Quality picks now.

These routes list the models Little Worker serves, and read one. They need no worker and change nothing. The list is every model it can send a run to. On Little Worker's servers, that is the model of each Quality and the model that searches the web, best first. A Little Worker that runs on your own computer with its model router off lists one default model. So the list can differ from one Little Worker to another.

The model object

Both routes on this page answer a model, or a page of them. Times are RFC 3339 in UTC, to the millisecond.

Fields

  • typestring
    Always model.
  • idstring
    The model's id, such as claude-sonnet-5-5. It is the model.id of a worker, and what a task's worker.model.id answers.
  • display_namestring
    The model's name as a person reads it. For a model whose name Little Worker does not hold, it is the id.
  • created_attime
    When the model was released. Little Worker does not hold release dates, so every model answers the epoch, 1970-01-01T00:00:00.000Z.
  • lifecyclestring
    Where the model is in its life. Every model is active today.

    One of active, deprecated, retired

  • deprecated_attime or null
    When the model was deprecated. null while it is active.
  • retires_attime or null
    When the model retires. null when no date is set.
  • linestring or null
    The Claude line the model belongs to, read from its id. null for any other model.

    One of haiku, sonnet, opus, fable, mythos

  • max_input_tokensnumber or null
    The most tokens the model reads at once. null: Little Worker does not hold this fact.
  • max_tokensnumber or null
    The most tokens the model writes in one answer. null: Little Worker does not hold this fact.
  • allowed_fallback_modelsarray of strings or null
    The models that may stand in for this one. null today.
  • capabilitiesobject
    What the model can do, in the shape of Claude's model list. Every key below is always there, and each one holds supported. Little Worker holds the efforts of each model, so effort is true to the model; every other capability reads supported: false, which means Little Worker does not claim it.
    Show its 11 fields
    • effortobject
      The efforts the model takes. A Claude model takes low to max, a Haiku model stops at high, and any other model takes low to xhigh. Those other models also take none and minimal as a worker's model.effort, which this object has no key for.
      Show its 6 fields
      • lowobject
        Whether the model takes the low effort.
        Show its 1 fields
        • supportedboolean
          true when it does.
      • mediumobject
        Whether the model takes the medium effort.
        Show its 1 fields
        • supportedboolean
          true when it does.
      • highobject
        Whether the model takes the high effort.
        Show its 1 fields
        • supportedboolean
          true when it does.
      • xhighobject
        Whether the model takes the xhigh effort.
        Show its 1 fields
        • supportedboolean
          true when it does.
      • maxobject
        Whether the model takes the max effort.
        Show its 1 fields
        • supportedboolean
          true when it does.
      • supportedboolean
        true when the model takes any effort.
    • batchobject
      { supported }. Always false today.
    • citationsobject
      { supported }. Always false today.
    • code_executionobject
      { supported }. Always false today.
    • compactionobject
      { summarize, supported }. Always false today.
    • context_managementobject
      { clear_thinking_20251015, clear_tool_uses_20250919, compact_20260112, supported }. Always false today.
    • image_inputobject
      { supported }. Always false today.
    • pdf_inputobject
      { supported }. Always false today.
    • server_toolsobject
      { code_execution, web_search, supported }. Always false today.
    • structured_outputsobject
      { supported }. Always false today.
    • thinkingobject
      { supported, types: { adaptive, disabled, enabled } }. Always false today.
  • providerstring
    Who serves the model, read from its id.

    One of anthropic, openai, openrouter, other

  • fast_modeobject
    Whether speed: "fast" is honored on this model. false for every model today, so a fast worker runs at standard speed.
    Show its 1 fields
    • supportedboolean
      true when it is.
  • region_pinobject
    Whether inference_geo can pin the region that serves the model. false for every model today.
    Show its 1 fields
    • supportedboolean
      true when it can.
  • mid_task_system_messageobject
    Whether a system.message sent in the middle of a task reaches the model in its own system role. It does for the Claude models Anthropic lists for it and for OpenAI's models, and not for any other model, OpenRouter's included.
    Show its 1 fields
    • supportedboolean
      true when it does.
  • list_priceobject or null
    What the model costs at list price. null for a model whose price Little Worker does not hold.
    Show its 5 fields
    • per_tokensinteger
      The number of tokens each amount is for: always 1000000000, a billion, so every price is whole cents.
    • inputmoney
      The price of tokens the model reads.
      Show its 2 fields
      • amountstring
        Whole US cents, as a string, for the per_tokens tokens: "200000" is $2,000.00 for a billion tokens, or $2.00 for a million.
      • currencystring
        Always USD.
    • outputmoney
      The price of tokens the model writes.
      Show its 2 fields
      • amountstring
        Whole US cents, as a string, for the per_tokens tokens: "200000" is $2,000.00 for a billion tokens, or $2.00 for a million.
      • currencystring
        Always USD.
    • cache_readmoney
      The price of tokens read from the cache.
      Show its 2 fields
      • amountstring
        Whole US cents, as a string, for the per_tokens tokens: "200000" is $2,000.00 for a billion tokens, or $2.00 for a million.
      • currencystring
        Always USD.
    • cache_writemoney
      The price of tokens written to the cache.
      Show its 2 fields
      • amountstring
        Whole US cents, as a string, for the per_tokens tokens: "200000" is $2,000.00 for a billion tokens, or $2.00 for a million.
      • currencystring
        Always USD.
Model object
{
  "type": "model",
  "id": "claude-sonnet-5-5",
  "display_name": "Claude Sonnet 5.5",
  "created_at": "1970-01-01T00:00:00.000Z",
  "lifecycle": "active",
  "deprecated_at": null,
  "retires_at": null,
  "line": "sonnet",
  "max_input_tokens": null,
  "max_tokens": null,
  "allowed_fallback_models": null,
  "capabilities": {
    "batch": {
      "supported": false
    },
    "citations": {
      "supported": false
    },
    "code_execution": {
      "supported": false
    },
    "compaction": {
      "summarize": {
        "supported": false
      },
      "supported": false
    },
    "context_management": {
      "clear_thinking_20251015": {
        "supported": false
      },
      "clear_tool_uses_20250919": {
        "supported": false
      },
      "compact_20260112": {
        "supported": false
      },
      "supported": false
    },
    "image_input": {
      "supported": false
    },
    "pdf_input": {
      "supported": false
    },
    "server_tools": {
      "code_execution": {
        "supported": false
      },
      "web_search": {
        "supported": false
      },
      "supported": false
    },
    "structured_outputs": {
      "supported": false
    },
    "thinking": {
      "supported": false,
      "types": {
        "adaptive": {
          "supported": false
        },
        "disabled": {
          "supported": false
        },
        "enabled": {
          "supported": false
        }
      }
    },
    "effort": {
      "low": {
        "supported": true
      },
      "medium": {
        "supported": true
      },
      "high": {
        "supported": true
      },
      "xhigh": {
        "supported": true
      },
      "max": {
        "supported": true
      },
      "supported": true
    }
  },
  "provider": "anthropic",
  "fast_mode": {
    "supported": false
  },
  "region_pin": {
    "supported": false
  },
  "mid_task_system_message": {
    "supported": true
  },
  "list_price": {
    "per_tokens": 1000000000,
    "input": {
      "amount": "200000",
      "currency": "USD"
    },
    "output": {
      "amount": "1000000",
      "currency": "USD"
    },
    "cache_read": {
      "amount": "10000",
      "currency": "USD"
    },
    "cache_write": {
      "amount": "250000",
      "currency": "USD"
    }
  }
}

List models

GET/models

List the models, best first. A model list pages by model id, as Claude's does: send the last_id of a page as after_id for the next one, or the first_id as before_id for the one before.

Query parameters

  • limitinteger
    How many to answer, 1 to 1,000. The default is 20.
  • after_idstring
    A model id, 1 to 256 characters. The page starts just after this model. Send this or before_id, not both.
  • before_idstring
    A model id, 1 to 256 characters. The page ends just before this model. Send this or after_id, not both.
  • lifecycle[]string
    Only models in this part of their life. Repeat it to name more than one, up to three.

    One of active, deprecated, retired

Returns

A page: data holds the models, first_id and last_id are the ids of its first and last model (null when it is empty), and has_more says whether more models follow in the direction you read.

Errors

StatusTypeWhen
400invalid_request_errorA query value is not valid, such as a limit outside 1 to 1,000, an after_id or before_id over 256 characters, or more than three lifecycle[] values, or both after_id and before_id are sent (error_code validation_error). An after_id or before_id that names no model in the list as filtered is invalid_cursor.
401authentication_errorThe key is missing, removed, or not a key. Send it in x-api-key.
429rate_limit_errorThe workspace made too many requests this minute. Wait the seconds in Retry-After, then try again.
curl "https://core.thelittleworker.com/api/v1/models?limit=2" \
  -H "x-api-key: $LITTLE_WORKER_API_KEY" \
  -H "Little-Worker-Version: 2026-10-19"
Response200
{
  "data": [
    {
      "type": "model",
      "id": "claude-sonnet-5-5",
      "display_name": "Claude Sonnet 5.5",
      "created_at": "1970-01-01T00:00:00.000Z",
      "lifecycle": "active",
      "deprecated_at": null,
      "retires_at": null,
      "line": "sonnet",
      "max_input_tokens": null,
      "max_tokens": null,
      "allowed_fallback_models": null,
      "capabilities": {
        "batch": {
          "supported": false
        },
        "citations": {
          "supported": false
        },
        "code_execution": {
          "supported": false
        },
        "compaction": {
          "summarize": {
            "supported": false
          },
          "supported": false
        },
        "context_management": {
          "clear_thinking_20251015": {
            "supported": false
          },
          "clear_tool_uses_20250919": {
            "supported": false
          },
          "compact_20260112": {
            "supported": false
          },
          "supported": false
        },
        "image_input": {
          "supported": false
        },
        "pdf_input": {
          "supported": false
        },
        "server_tools": {
          "code_execution": {
            "supported": false
          },
          "web_search": {
            "supported": false
          },
          "supported": false
        },
        "structured_outputs": {
          "supported": false
        },
        "thinking": {
          "supported": false,
          "types": {
            "adaptive": {
              "supported": false
            },
            "disabled": {
              "supported": false
            },
            "enabled": {
              "supported": false
            }
          }
        },
        "effort": {
          "low": {
            "supported": true
          },
          "medium": {
            "supported": true
          },
          "high": {
            "supported": true
          },
          "xhigh": {
            "supported": true
          },
          "max": {
            "supported": true
          },
          "supported": true
        }
      },
      "provider": "anthropic",
      "fast_mode": {
        "supported": false
      },
      "region_pin": {
        "supported": false
      },
      "mid_task_system_message": {
        "supported": true
      },
      "list_price": {
        "per_tokens": 1000000000,
        "input": {
          "amount": "200000",
          "currency": "USD"
        },
        "output": {
          "amount": "1000000",
          "currency": "USD"
        },
        "cache_read": {
          "amount": "10000",
          "currency": "USD"
        },
        "cache_write": {
          "amount": "250000",
          "currency": "USD"
        }
      }
    },
    {
      "type": "model",
      "id": "claude-haiku-5-5",
      "display_name": "Claude Haiku 5.5",
      "created_at": "1970-01-01T00:00:00.000Z",
      "lifecycle": "active",
      "deprecated_at": null,
      "retires_at": null,
      "line": "haiku",
      "max_input_tokens": null,
      "max_tokens": null,
      "allowed_fallback_models": null,
      "capabilities": {
        "batch": {
          "supported": false
        },
        "citations": {
          "supported": false
        },
        "code_execution": {
          "supported": false
        },
        "compaction": {
          "summarize": {
            "supported": false
          },
          "supported": false
        },
        "context_management": {
          "clear_thinking_20251015": {
            "supported": false
          },
          "clear_tool_uses_20250919": {
            "supported": false
          },
          "compact_20260112": {
            "supported": false
          },
          "supported": false
        },
        "image_input": {
          "supported": false
        },
        "pdf_input": {
          "supported": false
        },
        "server_tools": {
          "code_execution": {
            "supported": false
          },
          "web_search": {
            "supported": false
          },
          "supported": false
        },
        "structured_outputs": {
          "supported": false
        },
        "thinking": {
          "supported": false,
          "types": {
            "adaptive": {
              "supported": false
            },
            "disabled": {
              "supported": false
            },
            "enabled": {
              "supported": false
            }
          }
        },
        "effort": {
          "low": {
            "supported": true
          },
          "medium": {
            "supported": true
          },
          "high": {
            "supported": true
          },
          "xhigh": {
            "supported": false
          },
          "max": {
            "supported": false
          },
          "supported": true
        }
      },
      "provider": "anthropic",
      "fast_mode": {
        "supported": false
      },
      "region_pin": {
        "supported": false
      },
      "mid_task_system_message": {
        "supported": true
      },
      "list_price": {
        "per_tokens": 1000000000,
        "input": {
          "amount": "10000",
          "currency": "USD"
        },
        "output": {
          "amount": "50000",
          "currency": "USD"
        },
        "cache_read": {
          "amount": "1000",
          "currency": "USD"
        },
        "cache_write": {
          "amount": "12500",
          "currency": "USD"
        }
      }
    }
  ],
  "first_id": "claude-sonnet-5-5",
  "has_more": true,
  "last_id": "claude-haiku-5-5"
}

Read a model

GET/models/{model_id}

Read one model. The answer is the model's entry in the list.

Path parameters

  • model_idstringRequired
    The model's id, 1 to 256 characters, such as claude-sonnet-5-5.

Returns

The model.

Errors

StatusTypeWhen
400invalid_request_errormodel_id is longer than 256 characters (error_code validation_error).
401authentication_errorThe key is missing, removed, or not a key. Send it in x-api-key.
404not_found_errorLittle Worker does not serve a model with this id (Model not found.). List the models to see the ones it does.
429rate_limit_errorThe workspace made too many requests this minute. Wait the seconds in Retry-After, then try again.
curl https://core.thelittleworker.com/api/v1/models/claude-sonnet-5-5 \
  -H "x-api-key: $LITTLE_WORKER_API_KEY" \
  -H "Little-Worker-Version: 2026-10-19"
Response200
{
  "type": "model",
  "id": "claude-sonnet-5-5",
  "display_name": "Claude Sonnet 5.5",
  "created_at": "1970-01-01T00:00:00.000Z",
  "lifecycle": "active",
  "deprecated_at": null,
  "retires_at": null,
  "line": "sonnet",
  "max_input_tokens": null,
  "max_tokens": null,
  "allowed_fallback_models": null,
  "capabilities": {
    "batch": {
      "supported": false
    },
    "citations": {
      "supported": false
    },
    "code_execution": {
      "supported": false
    },
    "compaction": {
      "summarize": {
        "supported": false
      },
      "supported": false
    },
    "context_management": {
      "clear_thinking_20251015": {
        "supported": false
      },
      "clear_tool_uses_20250919": {
        "supported": false
      },
      "compact_20260112": {
        "supported": false
      },
      "supported": false
    },
    "image_input": {
      "supported": false
    },
    "pdf_input": {
      "supported": false
    },
    "server_tools": {
      "code_execution": {
        "supported": false
      },
      "web_search": {
        "supported": false
      },
      "supported": false
    },
    "structured_outputs": {
      "supported": false
    },
    "thinking": {
      "supported": false,
      "types": {
        "adaptive": {
          "supported": false
        },
        "disabled": {
          "supported": false
        },
        "enabled": {
          "supported": false
        }
      }
    },
    "effort": {
      "low": {
        "supported": true
      },
      "medium": {
        "supported": true
      },
      "high": {
        "supported": true
      },
      "xhigh": {
        "supported": true
      },
      "max": {
        "supported": true
      },
      "supported": true
    }
  },
  "provider": "anthropic",
  "fast_mode": {
    "supported": false
  },
  "region_pin": {
    "supported": false
  },
  "mid_task_system_message": {
    "supported": true
  },
  "list_price": {
    "per_tokens": 1000000000,
    "input": {
      "amount": "200000",
      "currency": "USD"
    },
    "output": {
      "amount": "1000000",
      "currency": "USD"
    },
    "cache_read": {
      "amount": "10000",
      "currency": "USD"
    },
    "cache_write": {
      "amount": "250000",
      "currency": "USD"
    }
  }
}

Type a few words, like “give a task” or “errors”.