Provider Configuration

Providers are tables of ~/.alta/config.toml. The provider editor writes the same file and keeps every setting it does not show; the Configuration file page of CodeAlta Desktop edits it whole and checks it as you type. A project can override a few values in <project>/.alta/config.toml (see Project settings).

Provider tables

Each provider is a [providers.<key>] table. Keys are lower case. codex and copilot get their type when type is left out.

The types are codex, copilot, xai, openai-chat, openai-responses, azure-openai, anthropic, google-genai, vertex-ai, mistral and claude-code. Plugins add others, such as acp for the agents of the ACP registry. Aliases such as openai, responses, aoai, gemini, vertex and github-copilot are read as these types.

A type your version of CodeAlta does not know, one a newer version added, leaves that provider out; its table stays in the file as written.

Common fields

Field	Purpose
`enabled`	Turns the provider on or off. Missing means on.
`display_name`	Name shown in the lists.
`icon`	Icon in CodeAlta Desktop: a brand logo such as `mistral`, `ollama` or `openrouter`, or a general icon such as `rocket`, `server` or `flask-conical`. Missing means the logo found from the key, name, URL and type.
`color`	Color of the icon, `#rgb` or `#rrggbb`. Missing means the colors of the logo.
`type`	Provider type, see above.
`model`	Default model id.
`reasoning_effort`	Default effort: `none`, `minimal`, `low`, `medium`, `high`, `xhigh` or `max`. Each model offers its own values.
`api_key` / `api_key_env`	The API key, or the environment variable that holds it. Prefer `api_key_env`.
`api_url`	Endpoint. Azure OpenAI, Codex and Copilot require HTTPS, except on localhost.
`network_timeout_seconds`	Network timeout of `openai-chat`, `openai-responses`, `azure-openai` and `codex`; 100 seconds when unset.
`protocol_trace`	Traces the requests of the OpenAI, Codex and Copilot providers.
`models_dev_provider_id`	The models.dev provider that describes the models.
`single_model_id`	The one model of an endpoint that lists none.
`models_include_regex`	A .NET regular expression: only the model ids it matches are shown, such as `^gemini-.*-pro`.
`sort_models`	`true` sorts the models by name; by default they keep the provider's order.
`profile`	Compatibility profile.
`compaction`	Compaction settings.
`model_overrides`	Model metadata overrides.
`extra_body`	More request-body fields, for `openai-chat` and `openai-responses`.
`request`	Headers and body fields of every request: Request customizations.
`model_request`	The same for one model: Model request overrides.

Fields by type

Type	Credentials and endpoint	Other fields
`openai-chat`, `openai-responses`	`api_key` or `api_key_env`; optional `api_url`, `organization_id`, `project_id`	`network_timeout_seconds`, `models_dev_provider_id`, `single_model_id`, `models_include_regex`, `extra_body`, `request`, `model_request`, `profile`, `compaction`, `model_overrides`, `protocol_trace`
`azure-openai`	`api_key` or `api_key_env`; the `api_url` of the Azure resource	`network_timeout_seconds`, `models_dev_provider_id`, `single_model_id`, `models_include_regex`, `profile`, `compaction`, `model_overrides`, `protocol_trace`
`anthropic`	`api_key` or `api_key_env`; optional `api_url`	`prompt_cache_ttl`, `refusal_fallback`, `models_dev_provider_id`, `single_model_id`, `models_include_regex`, `request.headers`, `request.remove_headers`, `profile`, `compaction`, `model_overrides`
`google-genai`, `mistral`	`api_key` or `api_key_env`; optional `api_url`	`models_dev_provider_id`, `single_model_id`, `models_include_regex`, `request.headers`, `request.remove_headers`, `profile`, `compaction`, `model_overrides`
`vertex-ai`	`project` and `location`; optional `api_url`	the same as `google-genai`
`codex`	ChatGPT sign-in, no key; optional `api_url`	`network_timeout_seconds`, `models_include_regex`, `auth_source`, `account_id`, `max_concurrent_requests`, `text_verbosity`, `service_tier`, `web_search`, `include_encrypted_reasoning`, `model_discovery`, `response_transport`, `send_responses_beta_header`, `send_installation_id`, `installation_id_source`, `experimental`, `codex_home`, `profile`, `compaction`, `protocol_trace`
`copilot`	GitHub sign-in; optional `api_url`	`auth_source`, `github_enterprise_url`, `github_token_env`, `copilot_token_env`, `model_discovery`, `enable_model_policies`, `include_preview_models`, `experimental`, `single_model_id`, `models_include_regex`, `models_dev_provider_id`, `profile`, `compaction`, `model_overrides`, `protocol_trace`
`xai`	xAI sign-in; optional `api_url`	`auth_source`, `model_discovery`, `single_model_id`, `models_include_regex`, `models_dev_provider_id`, `request`, `model_request`, `profile`, `compaction`, `model_overrides`, `protocol_trace`
`claude-code`	none: `api_key`, `api_key_env` and `api_url` are refused	`config_dir`, `command`, `args`, `permission_mode`, `anthropic_api_key`, `single_model_id`, `models_include_regex` (see Claude Code settings)
`acp`	none: the agent signs in by itself	`command`, `arguments`, `env`, `permission_mode`, and `agent` and `agent_version` for an agent of the registry (see Write one by hand)

Codex, Copilot and xAI

The fields of the subscriptions take these values:

Provider	Field	Values
Codex	`auth_source`	`codealta_oauth` only
Codex	`model_discovery`	`codex_endpoint_with_static_fallback` (default), `codex_endpoint`, `static`
Codex	`response_transport`	`http` (default), `websocket_with_http_fallback`
Codex	`text_verbosity`	`low`, `medium`, `high`
Codex	`web_search`	`cached` (default), `live`, `disabled`
Codex	`service_tier`	`priority` (or `fast`), `default`
Codex	`installation_id_source`	`codealta_state`, `codex_home_import`, `codex_home_readonly`
Copilot	`auth_source`	`github_device_flow` (default), `github_token_env`, `copilot_token_env`
Copilot	`model_discovery`	`copilot_endpoint_with_static_fallback` (default), `copilot_endpoint`, `static`
xAI	`auth_source`	`xai_browser_oauth`, `xai_device_flow`
xAI	`model_discovery`	`xai_endpoint_with_static_fallback` (default), `xai_endpoint`, `static`

github_token_env and copilot_token_env name the variable that holds the token of their auth_source, and are required with it.
A static list, or the fallback to it, does not prove that a model is available to your account; a sign-in or permission error is never hidden behind it.
Codex sends its requests to https://api.openai.com/v1. The old https://chatgpt.com/backend-api/codex URL is read as that address; a custom api_url is left as it is.
Codex account_id does not choose an account: the account you signed in with does. installation_id_source only sets optional telemetry headers.
send_responses_beta_header is off by default; turn it on only for an endpoint that needs it.
Codex takes no api_key, api_key_env, extra_body, request or model_request.

Compatibility profile

[providers.<key>.profile] is for an endpoint that behaves differently from the API it imitates:

Field	Meaning
`supports_developer_role`	Requests may use a developer message.
`supports_store`	Requests may send the `store` flag.
`supports_reasoning_effort`	`reasoning_effort` can be sent.
`streams_usage`	Streamed answers include usage.
`supports_thought_signatures`	The provider keeps thought signatures between requests.
`requires_tool_result_name`	A tool result must carry the tool name.
`requires_assistant_after_tool_result`	An assistant message must follow the tool results.
`supports_tool_result_images`	A tool result can carry an image. When `false`, the image goes in a user message after the tool results. By default only OpenAI's own Responses endpoints take images in tool results.
`supports_cache_control`	Anthropic Messages requests carry the prompt-cache markers (on by default). Set `false` for a compatible endpoint that refuses them: it then caches nothing.
`supports_tool_deferral`	Anthropic Messages requests can defer tools, so the model loads MCP tools on demand. By default only the Claude API does, for Claude 4.5 models and later.
`supports_strict_tools`	Strict tool schemas are supported.
`thinking_format`	Name of the provider's thinking format.
`max_tokens_field_name`	Body field of the output limit, such as `max_output_tokens` or `max_completion_tokens`.
`reasoning_field_names`	Answer fields read as reasoning.
`reasoning_input_field_name`	Assistant-message field that carries earlier reasoning back.
`supports_parallel_tool_calls`	Send the Chat Completions `parallel_tool_calls` flag when there are tools (on by default).

The built-in Alibaba and DeepSeek providers come with these settings, so you do not restate them:

[providers.alibaba.profile]
supports_developer_role = false
supports_store = false
supports_reasoning_effort = false
max_tokens_field_name = "max_tokens"

[providers.alibaba.request.extra_body]
enable_thinking = true
preserve_thinking = true

[providers.deepseek.profile]
supports_developer_role = false
supports_store = false
max_tokens_field_name = "max_tokens"
reasoning_input_field_name = "reasoning_content"

[providers.deepseek.request.extra_body.thinking]
type = "enabled"

Values you write in profile, request or extra_body take precedence over them.

Single-model endpoints

single_model_id is for an endpoint that serves one model or lists none. The built-in MiniMax provider uses it:

[providers.minimax]
single_model_id = "MiniMax-M2.7"

Request customizations

[providers.<key>.request] adds headers, and body fields for OpenAI-compatible providers:

[providers.openrouter]
type = "openai-responses"
api_key_env = "CODEALTA_OPENROUTER_API_KEY"
api_url = "https://openrouter.ai/api/v1"

[providers.openrouter.request.headers]
HTTP-Referer = "https://codealta.dev"
X-Title = "CodeAlta"

[providers.openrouter.request.extra_body]
include_usage = true

[providers.openrouter.request]
remove_headers = ["X-Unwanted-Default"]
remove_extra_body = ["unsupported_default"]

The values apply in this order, the last winning:

the defaults of CodeAlta and of the built-in provider;
request.remove_headers and request.remove_extra_body, which remove defaults;
request.headers and request.extra_body;
a top-level extra_body, which is still read;
the authentication headers of the provider, which cannot be removed or replaced.

Authorization, api-key and x-api-key are reserved for authentication. Traces hide the headers whose names look like secrets (Authorization, *-key, *token*, *secret*).

Session values in headers

For openai-chat and openai-responses, a header value in request.headers or model_request.<model-id>.headers can name values filled for each request:

Placeholder	Value
`${session.id}`	The id of the session: the same for every request of a conversation, kept when it resumes.
`${run.id}`	The id of the current run: one prompt and the work it starts.
`${model.id}`	The id of the selected model.
`${provider.key}`	The key of the provider, such as `opencode-go`.

OpenCode Go and Zen ask for an x-opencode-session header that stays the same for a conversation, which keeps it on the same backend and its prompt cache:

[providers.opencode-go]
type = "openai-chat"
api_url = "https://opencode.ai/inference/go/v1"
api_key_env = "CODEALTA_OPENCODE_GO_API_KEY"
models_dev_provider_id = "opencode-go"

[providers.opencode-go.request.headers]
"x-opencode-session" = "${session.id}"

A value can mix text and placeholders, such as "codealta-${session.id}". An unknown ${...} is sent as written. A request outside a session, such as the model list, leaves out the headers that name a placeholder. Other provider types send the value as written.

Model request overrides

[providers.<key>.model_request.<model-id>] changes requests only for that model. Model ids match as in model metadata overrides.

[providers.openai.model_request."gpt-5.5"]
remove_extra_body = ["reasoning_split"]

[providers.openai.model_request."gpt-5.5".extra_body]
reasoning = { effort = "high" }

[providers.openai.model_request."gpt-5.5".headers]
X-Model-Mode = "high-reasoning"

Model metadata overrides

[providers.<key>.model_overrides.<model-id>] corrects what CodeAlta knows of a model, when the provider and models.dev say nothing or are wrong. It changes the model lists, the context usage and when compaction starts, not the requests.

Field	Effect
`display_name`	Name of the model.
`description`	Description of the model.
`context_window`	Total context window, in tokens.
`input_token_limit`	Maximum input tokens.
`output_token_limit`	Maximum output tokens.
`max_tokens`	Output limit sent with requests; `output_token_limit` when unset.
`supports_reasoning`	The model reasons.
`supports_tool_call`	The model calls tools.
`supports_attachments`	The model reads images and attachments.
`supports_structured_output`	The model gives structured output.

Quote a model id that contains dots, slashes or other punctuation. A model id also matches its form with a date suffix.

[providers.openai.model_overrides."your-model-id"]
context_window = 200000
input_token_limit = 180000
output_token_limit = 20000
supports_reasoning = true
supports_tool_call = true

Models of a provider

models_dev_provider_id names the models.dev provider that describes the models; without it, CodeAlta finds one (see Models and reasoning).
models_include_regex keeps only the models whose id it matches, such as gpt-5|claude.
single_model_id gives the one model of an endpoint that lists none.
sort_models = true sorts them by name.

Compaction settings

[providers.<key>.compaction] tunes when and how CodeAlta compacts the sessions of a provider:

[providers.openai.compaction]
enabled = true
ratio = 0.95
summary_output_ratio = 0.10
post_compaction_target_ratio = 0.10
summary_share_of_target = 0.40
file_context_share_of_summary_target = 0.15
keep_last_user_message = true
allow_split_turn = true

Field	Default	Meaning
`enabled`	`true`	Compacts by itself when the context reaches `ratio`.
`ratio`	`0.95`	Share of the input limit that starts a compaction; above 0, at most 1.
`summary_output_ratio`	`0.10`	Output budget of the summary, as a share of the input limit; above 0, at most 0.50.
`post_compaction_target_ratio`	`0.10`	Size the context aims for after compaction; above 0, at most 1.
`summary_share_of_target`	`0.40`	Share of that target for the summary; above 0, at most 1.
`file_context_share_of_summary_target`	`0.15`	Share of the summary for the content of files; 0 to 1.
`keep_last_user_message`	`true`	Keeps your last message as it is.
`allow_split_turn`	`true`	Lets compaction split a large turn.

The values are checked when the file is saved and at startup. Most users keep the defaults.