Struct AgentConfig 

pub struct AgentConfig {

    pub provider: String,
    pub api_key_env: String,
    pub default_model: String,
    pub theme: String,
    pub system_prompt_mode: SystemPromptMode,
    pub max_system_prompt_tokens: u64,
    pub system_prompt_budget_warning: bool,
    pub trim_system_prompt: bool,
    pub tool_documentation_mode: ToolDocumentationMode,
    pub shell_prompt_profile: ShellPromptProfile,
    pub enable_split_tool_results: bool,
    pub todo_planning_mode: bool,
    pub ui_surface: UiSurfacePreference,
    pub max_conversation_turns: usize,
    pub idle_turn_limit: usize,
    pub reasoning_effort: ReasoningEffortLevel,
    pub allow_reasoning_effort_downgrade: bool,
    pub verbosity: VerbosityLevel,
    pub temperature: f32,
    pub refine_temperature: f32,
    pub enable_self_review: bool,
    pub max_review_passes: usize,
    pub refine_prompts_enabled: bool,
    pub refine_prompts_max_passes: usize,
    pub refine_prompts_model: String,
    pub small_model: AgentSmallModelConfig,
    pub prompt_suggestions: AgentPromptSuggestionsConfig,
    pub onboarding: AgentOnboardingConfig,
    pub project_doc_max_bytes: usize,
    pub project_doc_fallback_filenames: Vec<String>,
    pub instruction_max_bytes: usize,
    pub instruction_files: Vec<String>,
    pub instruction_excludes: Vec<String>,
    pub instruction_import_max_depth: usize,
    pub persistent_memory: PersistentMemoryConfig,
    pub custom_api_keys: BTreeMap<String, String>,
    pub credential_storage_mode: AuthCredentialsStoreMode,
    pub checkpointing: AgentCheckpointingConfig,
    pub vibe_coding: AgentVibeCodingConfig,
    pub max_task_retries: u32,
    pub harness: AgentHarnessConfig,
    pub codex_app_server: AgentCodexAppServerConfig,
    pub include_temporal_context: bool,
    pub temporal_context_use_utc: bool,
    pub include_working_directory: bool,
    pub include_structured_reasoning_tags: Option<bool>,
    pub user_instructions: Option<String>,
    pub require_plan_confirmation: bool,
    pub circuit_breaker: CircuitBreakerConfig,
    pub open_responses: OpenResponsesConfig,
}

Agent-wide configuration

Fields

provider: String

Active provider for single-agent runs.

api_key_env: String

Environment variable that stores the API key for the active provider

default_model: String

Default model for new conversations.

theme: String

UI theme identifier controlling ANSI styling

system_prompt_mode: SystemPromptMode

System prompt mode controlling prompt verbosity and token overhead. Options target lean base prompts: minimal (~500 tokens), lightweight (~750 tokens), default and specialized (~900 tokens) before dynamic runtime addenda.

max_system_prompt_tokens: u64

Soft token budget for the fully composed system prompt (character-based estimate, ~4 chars/token). Includes workspace instructions, guidelines, and runtime addenda on top of the base prompt.

system_prompt_budget_warning: bool

Warn when the composed system prompt exceeds max_system_prompt_tokens.

trim_system_prompt: bool

Trim low-priority advisory system prompt sections when over budget. Base, shell-safety, and active-tool contracts are never trimmed.

tool_documentation_mode: ToolDocumentationMode

Tool documentation mode controlling token overhead for tool definitions Options: minimal, progressive (default, ~1.8k tokens for the builtin catalog), full Progressive: complete tool and parameter descriptions; only unusually long tails are trimmed at a sentence boundary (recommended) Minimal: first sentence of each tool description and no parameter descriptions (power users) Full: every tool and parameter description sent unmodified

shell_prompt_profile: ShellPromptProfile

Shell syntax profile used in model-facing command examples. This controls prompt wording only; command policy remains in the runtime. Values: auto, unix_like, powershell.

enable_split_tool_results: bool

Enable split tool results for massive token savings (Phase 4) When enabled, tools return dual-channel output:

• llm_content: Concise summary sent to LLM (token-optimized, 53-95% reduction)
• ui_content: Rich output displayed to user (full details preserved) Applies to: exec_command, code_search, apply_patch, and retained internal helpers Default: true (opt-out for compatibility), recommended for production use

todo_planning_mode: bool

Enable TODO planning helper mode for structured task management

ui_surface: UiSurfacePreference

Preferred rendering surface for the interactive chat UI (inline by default; auto, alternate, inline)

max_conversation_turns: usize

Maximum number of conversation turns before auto-termination

idle_turn_limit: usize

Maximum consecutive idle turns (no tool calls, no meaningful response) before the agent runner treats the session as stalled and aborts the loop.

reasoning_effort: ReasoningEffortLevel

Reasoning depth for capable models (none to max).

allow_reasoning_effort_downgrade: bool

Permit a lower supported effort with an explicit harness diagnostic.

verbosity: VerbosityLevel

Output verbosity for supported models (low to high).

temperature: f32

Sampling temperature (0.0 precise to 1.0 creative).

refine_temperature: f32

Temperature for prompt refinement (0.0-1.0).

enable_self_review: bool

Enable an extra self-review pass to refine final responses

max_review_passes: usize

Maximum number of self-review passes

refine_prompts_enabled: bool

Enable prompt refinement pass before sending to LLM

refine_prompts_max_passes: usize

Max refinement passes for prompt writing

refine_prompts_model: String

Optional model override for the refiner (empty = auto pick efficient sibling)

small_model: AgentSmallModelConfig

Small/lightweight model configuration for efficient operations Used for tasks like large file reads, parsing, git history, conversation summarization Typically 70-80% cheaper than main model; ~50% of VT Code’s calls use this tier

prompt_suggestions: AgentPromptSuggestionsConfig

Inline prompt suggestion configuration for the chat composer

onboarding: AgentOnboardingConfig

Session onboarding and welcome message configuration

project_doc_max_bytes: usize

Maximum bytes of AGENTS.md/CLAUDE.md content to load from project hierarchy

project_doc_fallback_filenames: Vec<String>

Additional filenames to check when AGENTS.md is absent at a directory level.

instruction_max_bytes: usize

Maximum bytes of instruction content to load from AGENTS.md/CLAUDE.md hierarchy

instruction_files: Vec<String>

Additional instruction files or globs to merge into the hierarchy

instruction_excludes: Vec<String>

Instruction files or globs to exclude from AGENTS.md and rules discovery

instruction_import_max_depth: usize

Maximum recursive @path import depth for instruction and rule files

persistent_memory: PersistentMemoryConfig

Durable per-repository memory for main sessions

custom_api_keys: BTreeMap<String, String>

Provider/key identities captured from interactive configuration flows

Note: Actual API keys are stored securely in the configured credential backend (OS keyring when available, otherwise encrypted file storage). Keys use <provider>/<environment-variable> identity keys and this field only tracks which identities have keys stored (for UI/migration purposes). The keys themselves are NOT serialized to the config file for security.

credential_storage_mode: AuthCredentialsStoreMode

Preferred storage backend for credentials (OAuth tokens, API keys, etc.)

• keyring: Use OS-specific secure storage (macOS Keychain, Windows Credential Manager, Linux Secret Service), with encrypted-file fallback when unavailable.
• file: Use AES-256-GCM encrypted file with machine-derived key
• auto: Try keyring first, fall back to file if unavailable

checkpointing: AgentCheckpointingConfig

Checkpointing configuration for automatic turn snapshots

vibe_coding: AgentVibeCodingConfig

Vibe coding configuration for lazy or vague request support

max_task_retries: u32

Maximum number of retries for agent task execution (default: 2) When an agent task fails due to retryable errors (timeout, network, 503, etc.), it will be retried up to this many times with exponential backoff

harness: AgentHarnessConfig

Harness configuration for turn-level budgets, telemetry, and execution limits

codex_app_server: AgentCodexAppServerConfig

Experimental Codex app-server sidecar configuration.

include_temporal_context: bool

Include current date/time in system prompt for temporal awareness Helps LLM understand context for time-sensitive tasks (default: true)

temporal_context_use_utc: bool

Use UTC instead of local time for temporal context in system prompts

include_working_directory: bool

Include current working directory in system prompt (default: true)

include_structured_reasoning_tags: Option<bool>

Controls inclusion of the structured reasoning tag instructions block.

Behavior:

• Some(true): always include structured reasoning instructions.
• Some(false): never include structured reasoning instructions.
• None (default): omit structured reasoning instructions in every prompt mode.

Models with native reasoning do not need visible reasoning tags, so the block is opt-in for users who want tag-based reasoning guidance.

user_instructions: Option<String>

Custom instructions provided by the user via configuration to guide agent behavior

require_plan_confirmation: bool

Require user confirmation before executing a plan generated in planning workflow When true, exiting planning workflow shows the implementation blueprint and requires explicit user approval before enabling edit tools.

circuit_breaker: CircuitBreakerConfig

Circuit breaker configuration for resilient tool execution Controls when the agent should pause and ask for user guidance due to repeated failures

open_responses: OpenResponsesConfig

Open Responses specification compliance configuration Enables vendor-neutral LLM API format for interoperable workflows

Implementations

impl AgentConfig

pub fn should_include_structured_reasoning_tags(&self) -> bool

Determine whether structured reasoning tag instructions should be included.

Trait Implementations

impl Clone for AgentConfig

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AgentConfig

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for AgentConfig

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for AgentConfig

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl JsonSchema for AgentConfig

fn schema_name() -> Cow<'static, str>

The name of the generated JSON Schema.

fn schema_id() -> Cow<'static, str>

Returns a string that uniquely identifies the schema produced by this type.

fn json_schema(generator: &mut SchemaGenerator) -> Schema

Generates a JSON Schema for this type.

fn inline_schema() -> bool

Whether JSON Schemas generated for this type should be included directly in parent schemas, rather than being re-used where possible using the $ref keyword.

impl Serialize for AgentConfig

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.