Models Configuration

This reference lists the fields of models.json. See Custom Models for examples and the file location (normally ~/.atomic/agent/models.json). Add "$schema": "https://raw.githubusercontent.com/bastani-inc/atomic/main/packages/coding-agent/schemas/models.schema.json" to models.json for editor validation and completion.

Providers

Each key under providers is a provider ID. A built-in provider ID changes that provider. Any other ID adds a provider, which needs baseUrl and an api at provider or model level.

Field	Type	Default	Description
`name`	string		Display name.
`baseUrl`	string		API base URL. Also applies to the provider’s built-in models.
`apiKey`	string		Literal key, “$NAME” environment interpolation, or “!command” output.
`api`	string		API for the provider’s models, such as “openai-completions”, “openai-responses”, “anthropic-messages”, or “google-generative-ai”.
`oauth`	`"radius"`		OAuth login flow. Requires baseUrl.
`headers`	object		Request headers. Values resolve like apiKey.
`compat`	object		Provider and model compatibility overrides.
`authHeader`	boolean	`false`	Whether to send the resolved API key as Authorization: Bearer.
`models`	`object[]`
`modelOverrides`	object

Models

Each models entry adds a model to the provider. An entry whose id matches an existing model replaces it.

Field	Type	Default	Description
`id`	string		Required. Model ID sent to the API.
`name`	string		Display name, also matched by —model patterns.
`api`	string		Overrides the provider api.
`baseUrl`	string		Overrides the provider baseUrl.
`reasoning`	boolean	`false`	Whether the model supports thinking.
`thinkingLevelMap`	object		Provider value sent for each thinking level. null marks a level unsupported. Levels the model does not map use the provider’s default value through high; xhigh and max are unsupported.
`input`	`("text" \| "image" \| "pdf")[]`	`["text"]`
`inputLimits`	object
`cost`	object
`cost.input`	number		Required. Input cost in USD per million tokens.
`cost.output`	number		Required. Output cost in USD per million tokens.
`cost.cacheRead`	number		Required. Cache-read cost in USD per million tokens.
`cost.cacheWrite`	number		Required. Cache-write cost in USD per million tokens.
`cost.tiers`	`object[]`		Request-wide pricing tiers. The highest matching input threshold applies to the full request.
`cost.tiers[].inputTokensAbove`	number		Required. Use this tier when total request input exceeds this token count.
`cost.tiers[].input`	number		Required. Input cost in USD per million tokens.
`cost.tiers[].output`	number		Required. Output cost in USD per million tokens.
`cost.tiers[].cacheRead`	number		Required. Cache-read cost in USD per million tokens.
`cost.tiers[].cacheWrite`	number		Required. Cache-write cost in USD per million tokens.
`promptCache`	object		Best-effort prompt cache lifetime in seconds for the short and long retention tiers. Atomic warms only tiers with a known lifetime.
`contextWindow`	number	`128000`	Context window in tokens.
`maxTokens`	number	`16384`	Maximum output tokens.
`samplingParams`	object		Fields merged into every request body. Applies only to OpenAI-compatible APIs.
`samplingParamsByThinkingLevel`	object		samplingParams per thinking level, merged over samplingParams.
`headers`	object		Request headers. Values resolve like apiKey.
`compat`	object		Provider and model compatibility overrides.

Model overrides

Each modelOverrides key is the ID of a built-in or extension model. Unknown IDs are ignored. Object fields, such as cost, merge with the model’s value field by field; other fields replace it.

Field	Type	Description
`name`	string	Display name, also matched by —model patterns.
`reasoning`	boolean	Whether the model supports thinking.
`thinkingLevelMap`	object	Provider value sent for each thinking level. null marks a level unsupported. Levels the model does not map use the provider’s default value through high; xhigh and max are unsupported.
`input`	`("text" \| "image" \| "pdf")[]`
`inputLimits`	object
`cost`	object
`cost.input`	number	Input cost in USD per million tokens.
`cost.output`	number	Output cost in USD per million tokens.
`cost.cacheRead`	number	Cache-read cost in USD per million tokens.
`cost.cacheWrite`	number	Cache-write cost in USD per million tokens.
`cost.tiers`	`object[]`	Request-wide pricing tiers. The highest matching input threshold applies to the full request.
`cost.tiers[].inputTokensAbove`	number	Required. Use this tier when total request input exceeds this token count.
`cost.tiers[].input`	number	Required. Input cost in USD per million tokens.
`cost.tiers[].output`	number	Required. Output cost in USD per million tokens.
`cost.tiers[].cacheRead`	number	Required. Cache-read cost in USD per million tokens.
`cost.tiers[].cacheWrite`	number	Required. Cache-write cost in USD per million tokens.
`promptCache`	object	Best-effort prompt cache lifetime in seconds for the short and long retention tiers. Atomic warms only tiers with a known lifetime.
`contextWindow`	number	Context window in tokens.
`maxTokens`	number	Maximum output tokens.
`samplingParams`	object	Fields merged into every request body. Applies only to OpenAI-compatible APIs.
`samplingParamsByThinkingLevel`	object	samplingParams per thinking level, merged over samplingParams.
`headers`	object	Request headers. Values resolve like apiKey.
`compat`	object	Provider and model compatibility overrides.

Input limits

See Image Input Limits.

Field	Type	Description
`maxRequestBytes`	integer	Maximum serialized provider request size in bytes.
`images`	object
`images.resize`	object	Cache-safe resize profile applied before a new image enters conversation history.
`images.resize.maxWidth`	integer
`images.resize.maxHeight`	integer
`images.resize.maxBytes`	integer	Maximum base64-encoded payload size in bytes.
`images.resize.jpegQuality`	integer
`images.maxPerMessage`	integer	Maximum images accepted in one provider message.
`images.maxPerRequest`	integer	Maximum images accepted across one provider request.

Compatibility

compat describes verified differences from an API’s standard request and response behavior. Model values override provider values per field. The fields that apply depend on the model’s api.

`openai-completions`

Field	Type	Default	Description
`supportsStore`	boolean		Whether the provider supports the store field. Default: auto-detected from URL.
`supportsDeveloperRole`	boolean		Whether the provider supports the developer role instead of system. Default: auto-detected from URL.
`supportsReasoningEffort`	boolean		Whether the provider supports reasoning_effort. Default: auto-detected from URL.
`supportsTemperature`	boolean	`true`	Whether the model accepts the temperature request field. When false, the provider omits temperature and also strips temperature, top_p, and top_k from samplingParams.
`supportsForcedToolChoice`	boolean	`true`	Whether the model accepts forced tool use (tool_choice “required” or a specific function). When false, the provider rejects a forced choice with an error instead of sending a request the model cannot honor. “auto” and “none” are never altered.
`supportsUsageInStreaming`	boolean	`true`	Whether the provider supports stream_options.include_usage for token usage in streaming responses.
`supportsFinishReason`	boolean	`true`	Whether streamed responses include finish_reason. When false, Atomic infers stop or toolUse when the stream ends.
`maxTokensField`	`"max_completion_tokens" \| "max_tokens"`		Which field to use for max tokens. Default: auto-detected from URL.
`requiresToolResultName`	boolean		Whether tool results require the name field. Default: auto-detected from URL.
`requiresAssistantAfterToolResult`	boolean		Whether a user message after tool results requires an assistant message in between. Default: auto-detected from URL.
`requiresThinkingAsText`	boolean		Whether thinking blocks must be converted to text blocks with <thinking> delimiters. Default: auto-detected from URL.
`requiresReasoningContentOnAssistantMessages`	boolean		Whether all replayed assistant messages must include an empty reasoning_content field when reasoning is enabled. Default: auto-detected from URL.
`thinkingFormat`	`"openai" \| "openrouter" \| "deepseek" \| "together" \| "baseten" \| "zai" \| "qwen" \| "chat-template" \| "qwen-chat-template" \| "string-thinking" \| "ant-ling"`		Format for reasoning or thinking parameters. When omitted, Atomic auto-detects the format from the provider URL. “openai” uses reasoning_effort, “openrouter” uses reasoning.effort, “deepseek” uses thinking.type plus reasoning_effort when supported, “together” uses reasoning.enabled plus reasoning_effort when supported, “baseten” uses configurable chat_template_args plus reasoning_effort when supported, “zai” uses thinking.type, “qwen” uses top-level enable_thinking, “qwen-chat-template” uses chat_template_kwargs.enable_thinking and preserve_thinking, “chat-template” uses configurable chat_template_kwargs, “string-thinking” uses top-level thinking, and “ant-ling” uses reasoning.effort only when the mapped effort is non-null.
`chatTemplateKwargs`	object		Kwargs sent as chat_template_kwargs when thinkingFormat is “chat-template”. Use $var with “thinking.enabled”, “thinking.effort”, or “thinking.budget” for Atomic-controlled values.
`chatTemplateArgs`	object		Arguments sent as chat_template_args when thinkingFormat is “baseten”. Use $var with “thinking.enabled”, “thinking.effort”, or “thinking.budget” for Atomic-controlled values.
`openRouterRouting`	object		OpenRouter provider routing preferences. Controls which upstream providers OpenRouter routes requests to. Sent as the provider field in the OpenRouter API request body. See https://openrouter.ai/docs/guides/routing/provider-selection.
`vercelGatewayRouting`	object		Vercel AI Gateway routing preferences. Controls which upstream providers the gateway routes requests to. See https://vercel.com/docs/ai-gateway/models-and-providers/provider-options.
`zaiToolStream`	boolean	`false`	Whether z.ai supports top-level tool_stream for streaming tool call deltas.
`thinkingTokenBudgetField`	`"thinking_token_budget" \| "thinking_budget" \| "thinking_budget_tokens"`		Top-level request field used to cap reasoning tokens from thinkingBudgets. Reasoning and the answer share max_tokens on these endpoints. “thinking_token_budget” is vLLM, “thinking_budget” is Qwen, DashScope, or SGLang, and “thinking_budget_tokens” is llama.cpp. Off by default and not set on the generated catalog.
`supportsThinkingTokenBudget`	boolean	`false`	Alias for thinkingTokenBudgetField: “thinking_token_budget” (vLLM). Prefer thinkingTokenBudgetField.
`supportsOpenAIGrammarTools`	boolean	`false`	Whether the provider supports OpenAI custom tools with Lark or regex grammar formats. When false, grammar-constrained tools fall back to normal function tools. The generated catalog enables this for capable models.
`supportsMidConvoSystemMessages`	boolean	`false`	Whether the exact model accepts system or developer messages after the conversation has started. When false, later system messages are folded into the leading system message. The generated catalog enables this for verified models.
`supportsMidConvoToolAdditions`	boolean	`false`	Whether system messages can introduce additional tools mid-conversation. Requires supportsMidConvoSystemMessages. The generated catalog enables this for capable models.
`supportsStrictMode`	boolean	`false`	Whether the provider supports the strict field in tool definitions. Generated capable models enable it explicitly.
`cacheControlFormat`	`"anthropic"`		Cache control convention for prompt caching. Anthropic applies cache_control markers to the system prompt, last tool definition, and last user, assistant, or tool-result text content.
`sendSessionAffinityHeaders`	boolean		Whether to send session-affinity data from options.sessionId. Default: true for OpenRouter endpoints, false otherwise.
`sessionAffinityFormat`	`"openai" \| "openai-nosession" \| "openrouter"`		Session-affinity header format. openai sends session_id, x-client-request-id, and x-session-affinity; openai-nosession sends x-client-request-id and x-session-affinity; openrouter sends x-session-id. Does not affect prompt_cache_key. Default: auto-detected.
`supportsLongCacheRetention`	boolean		Whether the provider supports long prompt cache retention (prompt_cache_retention: “24h” or Anthropic-style cache_control.ttl: “1h”, depending on format). Default: auto-detected from provider and URL.
`vllmPriority`	number		vLLM scheduler priority sent as the top-level priority request field. Lower values are handled earlier and the server default is 0. Only meaningful with —scheduling-policy priority. Off by default and not set on the generated catalog.

`openai-responses`

Also applies to azure-openai-responses and openai-codex-responses.

Field	Type	Default	Description
`supportsDeveloperRole`	boolean	`true`	Whether the provider supports the developer role instead of system.
`supportsMidConvoSystemMessages`	boolean	`false`	Whether the exact model accepts developer or system messages after the conversation has started. When false, later system messages are folded into the leading system message. The generated catalog enables this for verified models.
`sessionAffinityFormat`	`"openai" \| "openai-nosession" \| "openrouter"`		Session-affinity header format. openai sends session_id and x-client-request-id; openai-nosession sends x-client-request-id; openrouter sends x-session-id. Does not affect prompt_cache_key. Default: auto-detected.
`supportsLongCacheRetention`	boolean	`true`	Whether the provider supports long prompt cache retention. This uses prompt_cache_options.ttl: “30m” on GPT-5.6+ and prompt_cache_retention: “24h” on earlier models.
`supportsStrictMode`	boolean		Whether the provider supports strict JSON-schema function tools. Defaults are API-specific; generated OpenAI models enable it explicitly.
`supportsOpenAIGrammarTools`	boolean	`false`	Whether to emit OpenAI custom tools with Lark or regex grammar formats. When false, grammar-constrained tools fall back to normal function tools. The generated catalog enables this for capable models.
`supportsAdditionalTools`	boolean	`false`	Whether the model supports message-anchored additional_tools input items.
`supportsToolSearch`	boolean	`false`	Whether the model supports client-executed tool search for transcript-anchored additions.
`supportsExplicitPromptCacheMode`	boolean	`false`	Whether the model accepts prompt_cache_options. Older OpenAI models reject the parameter.
`supportsMidConvoEffort`	boolean	`false`	Whether thinking level changes are sent as configuration_update input items instead of changing reasoning.effort, so a change keeps the prompt cache. Only used by the openai-responses API, and ignored with Sign in with ChatGPT on the openai provider.
`supportsMaxOutputTokens`	boolean	`true`	Whether the provider accepts max_output_tokens. Some Codex-protocol gateways reject it.

`anthropic-messages`

Field	Type	Default	Description
`supportsEagerToolInputStreaming`	boolean	`true`	Whether the provider accepts per-tool eager_input_streaming. When false, the Anthropic provider omits tools[].eager_input_streaming and sends the legacy fine-grained-tool-streaming-2025-05-14 beta header for tool-enabled requests.
`supportsLongCacheRetention`	boolean	`true`	Whether the provider supports Anthropic long cache retention through cache_control.ttl.
`sendSessionAffinityHeaders`	boolean		Whether to send x-session-affinity from options.sessionId when caching is enabled. Required for providers like Fireworks that use session affinity for prompt cache routing; requests to the same replica maximize cache hits. Default: true for OpenRouter endpoints, false otherwise.
`sessionAffinityFormat`	`"openrouter"`		Session-affinity format. openrouter sends x-session-id; when unset, sends x-session-affinity.
`supportsCacheControlOnTools`	boolean	`true`	Whether the provider supports Anthropic-style cache_control markers on tool definitions. When false, cache_control is omitted from tool parameters. Some Anthropic-compatible providers, such as Fireworks, do not support this field on tools and may reject or ignore it.
`supportsTemperature`	boolean	`true`	Whether the model accepts the Anthropic temperature request field. Claude Opus 4.7+ rejects non-default values.
`forceAdaptiveThinking`	boolean	`false`	Whether to force adaptive thinking (thinking.type: adaptive plus output_config.effort) regardless of model ID. Built-in models that require adaptive thinking set this in generated metadata. Custom Anthropic-compatible providers can set this to true for any model whose upstream requires the adaptive format. Set false to opt out on overridden built-in models.
`allowEmptySignature`	boolean	`false`	Whether to replay empty thinking signatures instead of converting thinking to text.
`supportsStrictTools`	boolean	`false`	Whether the provider supports Anthropic strict tool schemas. Generated Anthropic models enable it explicitly.
`supportsMidConvoEffort`	boolean	`false`	Whether the exact model transport supports effort-only system messages and thinking binding controls.
`supportsMidConvoSystemMessages`	boolean	`false`	Whether the exact model accepts system-role messages inside the conversation. When false, later system messages are folded into the top-level system prompt.
`supportsMidConvoToolChanges`	boolean	`false`	Whether the exact model accepts mid-conversation tool_addition and tool_removal blocks. Requires supportsMidConvoSystemMessages.
`allowedFallbackModels`	`object[]`		Models Anthropic accepts for server-side refusal fallback, with local pricing metadata for returned fallback responses. When absent or empty, callers must omit fallbacks; Anthropic rejects the field for models with no permitted fallback targets.
`enforcesPreservedThinkingBinding`	boolean	`false`	Whether the model runs the Anthropic preserved-thinking conversation check, which rejects a request whose system prompt, tools, or earlier messages changed since a replayed thinking block was produced. When true, the provider sends the thinking-binding-controls-2026-08-01 beta header and thinking.block_binding.prefix_mismatch_behavior: “drop_block”, so a changed prefix drops the affected thinking blocks instead of failing the request.
`delegatesThinkingModelBinding`	boolean	`false`	Whether the API adjudicates thinking-block model binding itself, always dropping a block the target model cannot read. When true, an assistant turn produced by a different model on the same provider and API replays its signed thinking and redacted_thinking blocks unchanged instead of being rewritten into plain text.
`supportsForcedToolChoice`	boolean	`true`	Whether the model accepts forced tool use (tool_choice “any” or a specific tool). When false, the provider rejects a forced choice with an error instead of sending a request the model is guaranteed to refuse. “auto” and “none” are never altered.

`bedrock-converse-stream`

Field	Type	Default	Description
`supportsStrictMode`	boolean	`false`	Whether the model supports Bedrock strict tool schemas.
`supportsForcedToolChoice`	boolean	`true`	Whether the model accepts forced tool use (toolChoice “any” or a specific tool). When false, the provider rejects a forced choice with an error instead of sending a request that is guaranteed to fail. “auto” and “none” are never altered.
`supportsTemperature`	boolean	`true`	Whether the model accepts inferenceConfig.temperature. When false, the provider omits the field.

`mistral-conversations`

Field	Type	Default	Description
`supportsMidConvoSystemMessages`	boolean	`false`	Whether the exact model accepts system messages after the conversation has started. When false, later system messages are folded into the leading system message.

Atomic compatibility aliases

Field	Type	Default	Description
`supportsGrammarTools`	boolean		Atomic alias for supportsOpenAIGrammarTools. The canonical field wins if both are set.

Reference

Domain reference

Platform setup

Project

Models Configuration

Models Configuration

Providers

Models

Model overrides

Input limits

Compatibility

`openai-completions`

`openai-responses`

`anthropic-messages`

`bedrock-converse-stream`

`mistral-conversations`

Atomic compatibility aliases

​Models Configuration

​Providers

​Models

​Model overrides

​Input limits

​Compatibility

​openai-completions

​openai-responses

​anthropic-messages

​bedrock-converse-stream

​mistral-conversations

​Atomic compatibility aliases

Models Configuration

Providers

Models

Model overrides

Input limits

Compatibility

`openai-completions`

`openai-responses`

`anthropic-messages`

`bedrock-converse-stream`

`mistral-conversations`

Atomic compatibility aliases