Custom Model Import Configuration Guide

September 16, 2025 · View on GitHub

This guide explains how to configure custom models imported using Amazon Bedrock's Custom Model Import feature for use with Bedrock Engineer.

Overview

Using Amazon Bedrock's Custom Model Import feature, you can run open-source models published on platforms like Hugging Face on Bedrock. Bedrock Engineer can be configured to use these custom imported models in its chat functionality. (Experimental: Breaking changes may be made without notice)

Custom Model Import

DeepSeek-R1-Distill-Llama-8B Example

1. Model Download

# Install Git LFS (for Mac)
brew install git-lfs
git lfs install

# Clone the model
git clone https://huggingface.co/deepseek-ai/DeepSeek-R1-Distill-Llama-8B

2. tokenizer_config.json Configuration

To use the Converse API, change the chat_template to Llama-3.1 format. For other model types, please refer to the following documents:

Converse API code samples for custom model import

  {
  "add_bos_token": true,
  "add_eos_token": false,
  "bos_token": {
    "__type": "AddedToken",
    "content": "<|begin▁of▁sentence|>",
    "lstrip": false,
    "normalized": true,
    "rstrip": false,
    "single_word": false
  },
  "clean_up_tokenization_spaces": false,
  "eos_token": {
    "__type": "AddedToken",
    "content": "<|end▁of▁sentence|>",
    "lstrip": false,
    "normalized": true,
    "rstrip": false,
    "single_word": false
  },
  "legacy": true,
  "model_max_length": 16384,
  "pad_token": {
    "__type": "AddedToken",
    "content": "<|end▁of▁sentence|>",
    "lstrip": false,
    "normalized": true,
    "rstrip": false,
    "single_word": false
  },
  "sp_model_kwargs": {},
  "unk_token": null,
  "tokenizer_class": "LlamaTokenizerFast",
-   "chat_template": "{% if not add_generation_prompt is defined %}{% set add_generation_prompt = false %}{% endif %}{% set ns = namespace(is_first=false, is_tool=false, is_output_first=true, system_prompt='') %}{%- for message in messages %}{%- if message['role'] == 'system' %}{% set ns.system_prompt = message['content'] %}{%- endif %}{%- endfor %}{{bos_token}}{{ns.system_prompt}}{%- for message in messages %}{%- if message['role'] == 'user' %}{%- set ns.is_tool = false -%}{{'<|User|>' + message['content']}}{%- endif %}{%- if message['role'] == 'assistant' and message['content'] is none %}{%- set ns.is_tool = false -%}{%- for tool in message['tool_calls']%}{%- if not ns.is_first %}{{'<|Assistant|><|tool▁calls▁begin|><|tool▁call▁begin|>' + tool['type'] + '<|tool▁sep|>' + tool['function']['name'] + '\\n' + '```json' + '\\n' + tool['function']['arguments'] + '\\n' + '```' + '<|tool▁call▁end|>'}}{%- set ns.is_first = true -%}{%- else %}{{'\\n' + '<|tool▁call▁begin|>' + tool['type'] + '<|tool▁sep|>' + tool['function']['name'] + '\\n' + '```json' + '\\n' + tool['function']['arguments'] + '\\n' + '```' + '<|tool▁call▁end|>'}}{{'<|tool▁calls▁end|><|end▁of▁sentence|>'}}{%- endif %}{%- endfor %}{%- endif %}{%- if message['role'] == 'assistant' and message['content'] is not none %}{%- if ns.is_tool %}{{'<|tool▁outputs▁end|>' + message['content'] + '<|end▁of▁sentence|>'}}{%- set ns.is_tool = false -%}{%- else %}{% set content = message['content'] %}{% if '</think>' in content %}{% set content = content.split('</think>')[-1] %}{% endif %}{{'<|Assistant|>' + content + '<|end▁of▁sentence|>'}}{%- endif %}{%- endif %}{%- if message['role'] == 'tool' %}{%- set ns.is_tool = true -%}{%- if ns.is_output_first %}{{'<|tool▁outputs▁begin|><|tool▁output▁begin|>' + message['content'] + '<|tool▁output▁end|>'}}{%- set ns.is_output_first = false %}{%- else %}{{'\\n<|tool▁output▁begin|>' + message['content'] + '<|tool▁output▁end|>'}}{%- endif %}{%- endif %}{%- endfor -%}{% if ns.is_tool %}{{'<|tool▁outputs▁end|>'}}{% endif %}{% if add_generation_prompt and not ns.is_tool %}{{'<|Assistant|><think>\\n'}}{% endif %}",
+  "chat_template": "{{- bos_token }}\n{%- if custom_tools is defined %}\n    {%- set tools = custom_tools %}\n{%- endif %}\n{%- if not tools_in_user_message is defined %}\n    {%- set tools_in_user_message = true %}\n{%- endif %}\n{%- if not date_string is defined %}\n    {%- set date_string = \"26 Jul 2024\" %}\n{%- endif %}\n{%- if not tools is defined %}\n    {%- set tools = none %}\n{%- endif %}\n\n{#- This block extracts the system message, so we can slot it into the right place. #}\n{%- if messages[0]['role'] == 'system' %}\n    {%- set system_message = messages[0]['content']|trim %}\n    {%- set messages = messages[1:] %}\n{%- else %}\n    {%- set system_message = \"\" %}\n{%- endif %}\n\n{#- System message + builtin tools #}\n{{- \"<|start_header_id|>system<|end_header_id|>\\n\\n\" }}\n{%- if builtin_tools is defined or tools is not none %}\n    {{- \"Environment: ipython\\n\" }}\n{%- endif %}\n{%- if builtin_tools is defined %}\n    {{- \"Tools: \" + builtin_tools | reject('equalto', 'code_interpreter') | join(\", \") + \"\\n\\n\"}}\n{%- endif %}\n{{- \"Cutting Knowledge Date: December 2023\\n\" }}\n{{- \"Today Date: \" + date_string + \"\\n\\n\" }}\n{%- if tools is not none and not tools_in_user_message %}\n    {{- \"You have access to the following functions. To call a function, please respond with JSON for a function call.\" }}\n    {{- 'Respond in the format {\"name\": function name, \"parameters\": dictionary of argument name and its value}.' }}\n    {{- \"Do not use variables.\\n\\n\" }}\n    {%- for t in tools %}\n        {{- t | tojson(indent=4) }}\n        {{- \"\\n\\n\" }}\n    {%- endfor %}\n{%- endif %}\n{{- system_message }}\n{{- \"<|eot_id|>\" }}\n\n{#- Custom tools are passed in a user message with some extra guidance #}\n{%- if tools_in_user_message and not tools is none %}\n    {#- Extract the first user message so we can plug it in here #}\n    {%- if messages | length != 0 %}\n        {%- set first_user_message = messages[0]['content']|trim %}\n        {%- set messages = messages[1:] %}\n    {%- else %}\n        {{- raise_exception(\"Cannot put tools in the first user message when there's no first user message!\") }}\n{%- endif %}\n    {{- '<|start_header_id|>user<|end_header_id|>\\n\\n' -}}\n    {{- \"Given the following functions, please respond with a JSON for a function call \" }}\n    {{- \"with its proper arguments that best answers the given prompt.\\n\\n\" }}\n    {{- 'Respond in the format {\"name\": function name, \"parameters\": dictionary of argument name and its value}.' }}\n    {{- \"Do not use variables.\\n\\n\" }}\n    {%- for t in tools %}\n        {{- t | tojson(indent=4) }}\n        {{- \"\\n\\n\" }}\n    {%- endfor %}\n    {{- first_user_message + \"<|eot_id|>\"}}\n{%- endif %}\n\n{%- for message in messages %}\n    {%- if not (message.role == 'ipython' or message.role == 'tool' or 'tool_calls' in message) %}\n        {{- '<|start_header_id|>' + message['role'] + '<|end_header_id|>\\n\\n'+ message['content'] | trim + '<|eot_id|>' }}\n    {%- elif 'tool_calls' in message %}\n        {%- if not message.tool_calls|length == 1 %}\n            {{- raise_exception(\"This model only supports single tool-calls at once!\") }}\n        {%- endif %}\n        {%- set tool_call = message.tool_calls[0].function %}\n        {%- if builtin_tools is defined and tool_call.name in builtin_tools %}\n            {{- '<|start_header_id|>assistant<|end_header_id|>\\n\\n' -}}\n            {{- \"<|python_tag|>\" + tool_call.name + \".call(\" }}\n            {%- for arg_name, arg_val in tool_call.arguments | items %}\n                {{- arg_name + '=\"' + arg_val + '\"' }}\n                {%- if not loop.last %}\n                    {{- \", \" }}\n                {%- endif %}\n                {%- endfor %}\n            {{- \")\" }}\n        {%- else  %}\n            {{- '<|start_header_id|>assistant<|end_header_id|>\\n\\n' -}}\n            {{- '{\"name\": \"' + tool_call.name + '\", ' }}\n            {{- '\"parameters\": ' }}\n            {{- tool_call.arguments | tojson }}\n            {{- \"}\" }}\n        {%- endif %}\n        {%- if builtin_tools is defined %}\n            {#- This means we're in ipython mode #}\n            {{- \"<|eom_id|>\" }}\n        {%- else %}\n            {{- \"<|eot_id|>\" }}\n        {%- endif %}\n    {%- elif message.role == \"tool\" or message.role == \"ipython\" %}\n        {{- \"<|start_header_id|>ipython<|end_header_id|>\\n\\n\" }}\n        {%- if message.content is mapping or message.content is iterable %}\n            {{- message.content | tojson }}\n        {%- else %}\n            {{- message.content }}\n        {%- endif %}\n        {{- \"<|eot_id|>\" }}\n    {%- endif %}\n{%- endfor %}\n{%- if add_generation_prompt %}\n    {{- '<|start_header_id|>assistant<|end_header_id|>\\n\\n' }}\n{%- endif %}\n"
}

3. Upload to S3

export AWS_REGION=us-east-1
aws s3 mb s3://import-model-data-xxxxxxxx
aws s3 sync DeepSeek-R1-Distill-Llama-8B s3://import-model-data-xxxxxxxx/DeepSeek-R1-Distill-Llama-8B/

4. Execute Import Job

  • Create and execute an import job from the AWS console
  • After completion, obtain the model ARN

Bedrock Engineer Configuration

1. Adding Configuration to models.ts

Add the custom model definition to the src/common/models/models.ts file.

// Custom model example: DeepSeek-R1-Distill-Llama-8B
{
  baseId: 'arn:aws:bedrock:us-east-1:{{AWS_ACCOUNT_ID}}:imported-model/xxxxx',
  name: 'DeepSeek-R1-Distill-Llama-8B',
  provider: 'deepseek',
  category: 'text',
  toolUse: true,
  maxTokensLimit: 4096,
  supportsStreamingToolUse: false,
  availability: {
    base: ['us-east-1']
  }
}

2. Configuration Points

  • baseId: Specify the complete ARN of the custom model
  • supportsStreamingToolUse: Set streaming support status when using tools
  • availability: Specify the regions where the model is available

Configuration Parameter Details

Required Parameters

ParameterTypeDescriptionExample
baseIdstringModel ARNarn:aws:bedrock:us-east-1:123456789012:imported-model/xxxxx
namestringModel name displayed in UIDeepSeek-R1-Distill-Llama-8B
providerstringModel providerdeepseek
categorystringModel categorytext
toolUsebooleanTool usage supporttrue
maxTokensLimitnumberMaximum token count8192
availabilityobjectAvailable regions{ base: ['us-east-1'] }

Optional Parameters

ParameterTypeDescriptionDefault
supportsStreamingToolUsebooleanStreaming support when using toolstrue

Importance of supportsStreamingToolUse

This parameter indicates whether the model supports streaming API when using tools:

  • true: Streaming API + tool usage is possible
  • false: Use non-streaming API (Converse API) when using tools

Most custom imported models do not support streaming when using tools, so it is recommended to set this to false.

Troubleshooting

Common Errors and Solutions

1. ModelNotReadyException

Symptom: Model is not ready for inference error when calling the model

Cause: Custom model is still being prepared

Solution:

  • Wait a few minutes to several tens of minutes and retry
  • Error messages are displayed in the application UI

2. ARN Validation Error

Symptom: Error occurs during model ID validation

Cause: Improper handling of ARN format model ID

Solution:

  • Bedrock Engineer has implemented automatic ARN format detection
  • Specify the complete ARN in baseId

3. Streaming Error When Using Tools

Symptom: Error occurs when streaming with tool usage

Cause: Model does not support streaming when using tools

Solution:

  • Set supportsStreamingToolUse: false
  • Automatically switches to non-streaming API