runifold_agent/

agent.rs

use std::{collections::BTreeMap, future::Future, pin::Pin, sync::Arc, time::Instant};

use futures_util::{
    StreamExt,
    future::{Either, select},
};
use runifold_core::{
    BudgetEvent, CapabilitySet, DomainEvent, EffectId, EffectKind, EffectRequest, EventId,
    InvocationId, LifecycleEvent, RetrySafety, RunContext, RunError, RunErrorKind, RunEventKind,
    Usage,
};
use runifold_effect::{
    EffectExecutionContext, EffectExecutor, EffectExecutorErrorKind, EffectFuture, EffectHandler,
    EffectRecoveryPolicy, InMemoryEffectStore,
};
use runifold_model::{
    ContentPart, FeaturePolicy, Message, Model, ModelCallContext, ModelError, ModelErrorKind,
    ModelRef, ModelRequest, ModelResponse, ModelStreamAccumulator, OutputFormat, Role, ToolCall,
    ToolResult,
};
use runifold_tool::{ToolError, ToolErrorKind, ToolOutput, ToolRegistry};
use schemars::JsonSchema;
use serde::{Deserialize, Serialize};

use crate::checkpoint::CheckpointCursor;
use crate::stream::{AgentObserver, BufferedObserver, NoopObserver, emit_agent_event};
use crate::{AgentCheckpoint, AgentCheckpointPhase, AgentCheckpointState, ResumePolicy};
use crate::{
    AgentError, AgentEventStream, AgentGateway, AgentOutcome, AgentStreamEvent, CallableKind,
    GatewayError, GatewayErrorKind, StructuredAgent,
};

mod callable;
mod checkpointing;
mod execution;
mod observability;

/// A boxed, sendable future returned by an agent.
pub type AgentFuture<'a, T> = Pin<Box<dyn Future<Output = T> + Send + 'a>>;

/// How the agent handles tool failures that are safe for model recovery.
#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
#[non_exhaustive]
pub enum ToolErrorPolicy {
    /// Return safe execution failures to the model as failed tool results.
    #[default]
    ReturnToModel,
    /// Stop the agent immediately on every tool error.
    FailFast,
}

/// Local bounds and recovery behavior for an agent.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct AgentConfig {
    /// Local turn bound in addition to the shared run budget.
    pub max_turns: u32,
    /// Tool failure behavior.
    pub tool_error_policy: ToolErrorPolicy,
    /// Model capability-degradation policy.
    pub feature_policy: FeaturePolicy,
}

impl Default for AgentConfig {
    fn default() -> Self {
        Self {
            max_turns: 16,
            tool_error_policy: ToolErrorPolicy::ReturnToModel,
            feature_policy: FeaturePolicy::Strict,
        }
    }
}

/// One configured model-tool agent.
#[derive(Clone)]
pub struct Agent {
    pub(crate) name: String,
    pub(crate) model: Arc<dyn Model>,
    pub(crate) model_ref: ModelRef,
    pub(crate) instructions: Vec<Message>,
    pub(crate) tools: ToolRegistry,
    pub(crate) agents: AgentGateway,
    pub(crate) effects: EffectExecutor,
    pub(crate) effect_recovery: EffectRecoveryPolicy,
    pub(crate) config: AgentConfig,
    pub(crate) output_format: OutputFormat,
}

impl Agent {
    /// Starts a fluent builder for an Agent.
    pub fn builder(
        name: impl Into<String>,
        model: Arc<dyn Model>,
        model_ref: ModelRef,
    ) -> crate::AgentBuilder {
        crate::AgentBuilder::new(name, model, model_ref)
    }

    /// Creates an agent without instructions or tools.
    pub fn new(name: impl Into<String>, model: Arc<dyn Model>, model_ref: ModelRef) -> Self {
        Self {
            name: name.into(),
            model,
            model_ref,
            instructions: Vec::new(),
            tools: ToolRegistry::new(),
            agents: AgentGateway::new(),
            effects: EffectExecutor::new(Arc::new(InMemoryEffectStore::new())),
            effect_recovery: EffectRecoveryPolicy::RejectAmbiguous,
            config: AgentConfig::default(),
            output_format: OutputFormat::Text,
        }
    }

    /// Appends a system instruction.
    #[must_use]
    pub fn system(mut self, instruction: impl Into<String>) -> Self {
        self.instructions.push(Message::system(instruction));
        self
    }

    /// Installs the registry whose tools are exposed and executable.
    #[must_use]
    pub fn tools(mut self, tools: ToolRegistry) -> Self {
        self.tools = tools;
        self
    }

    /// Installs the gateway whose child agents are exposed and callable.
    #[must_use]
    pub fn agents(mut self, agents: AgentGateway) -> Self {
        self.agents = agents;
        self
    }

    /// Replaces the write-ahead effect coordinator shared by callables.
    #[must_use]
    pub fn effect_executor(mut self, effects: EffectExecutor) -> Self {
        self.effects = effects;
        self
    }

    /// Sets recovery behavior for ambiguous callable effects.
    #[must_use]
    pub const fn effect_recovery_policy(mut self, policy: EffectRecoveryPolicy) -> Self {
        self.effect_recovery = policy;
        self
    }

    /// Replaces local execution configuration.
    #[must_use]
    pub const fn with_config(mut self, config: AgentConfig) -> Self {
        self.config = config;
        self
    }

    /// Sets the desired format for the terminal model response.
    #[must_use]
    pub fn output_format(mut self, output_format: OutputFormat) -> Self {
        self.output_format = output_format;
        self
    }

    /// Requests strict structured output described by the Rust type `T`.
    #[must_use]
    pub fn structured_output<T>(self, name: impl Into<String>) -> Self
    where
        T: JsonSchema,
    {
        self.output_format(OutputFormat::typed::<T>(name))
    }

    /// Binds provider schema generation and local decoding to the same type.
    pub fn into_structured<T>(self, name: impl Into<String>) -> StructuredAgent<T>
    where
        T: JsonSchema,
    {
        StructuredAgent::new(self.structured_output::<T>(name))
    }

    /// Returns the stable local agent name.
    pub fn name(&self) -> &str {
        &self.name
    }

    /// Returns the provider and model identity used by this Agent.
    pub const fn model_ref(&self) -> &ModelRef {
        &self.model_ref
    }

    /// Returns capabilities for every Tool and child Agent exposed by this
    /// Agent.
    ///
    /// The returned set is not granted automatically. Applications explicitly
    /// decide whether to install it on a root or delegated Run.
    pub fn callable_capabilities(&self) -> CapabilitySet {
        let mut capabilities = CapabilitySet::new();
        for spec in self.tools.model_specs() {
            if let Some(descriptor) = self.tools.descriptor(&spec.name) {
                capabilities.grant(descriptor.capability());
            }
        }
        for spec in self.agents.model_specs() {
            if let Some(descriptor) = self.agents.descriptor(&spec.name) {
                capabilities.grant(descriptor.capability());
            }
        }
        capabilities
    }
}

impl std::fmt::Debug for Agent {
    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        formatter
            .debug_struct("Agent")
            .field("name", &self.name)
            .field("model_ref", &self.model_ref)
            .field("instructions", &self.instructions)
            .field("tools", &self.tools)
            .field("agents", &self.agents)
            .field("effects", &self.effects)
            .field("effect_recovery", &self.effect_recovery)
            .field("config", &self.config)
            .field("output_format", &self.output_format)
            .finish_non_exhaustive()
    }
}

#[cfg(test)]
mod tests;