holon 0.14.1

A headless, event-driven runtime for long-lived agents
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145

use std::sync::Arc;

use anyhow::{anyhow, Result};

use crate::{
    config::{AppConfig, ModelRef, ProviderTransportKind},
    context::ContextConfig,
    model_catalog::BuiltInModelCatalog,
    provider::fallback::FallbackProvider,
};

use super::{
    transports::{
        OpenAiChatCompletionsProvider, OpenAiCodexProvider, OpenAiCompactionPolicy, OpenAiProvider,
    },
    AgentProvider, AnthropicProvider,
};

#[derive(Clone)]
pub(crate) struct ProviderCandidate {
    pub(crate) model_ref: String,
    pub(crate) provider_name: String,
    pub(crate) provider: Arc<dyn AgentProvider>,
}

pub fn build_provider_from_config(config: &AppConfig) -> Result<Arc<dyn AgentProvider>> {
    build_provider_from_model_chain(config, &config.provider_chain())
}

pub fn build_provider_from_model_chain(
    config: &AppConfig,
    provider_chain: &[ModelRef],
) -> Result<Arc<dyn AgentProvider>> {
    let mut candidates = Vec::new();
    let mut errors = Vec::new();
    let disable_fallback = config.provider_fallback_disabled();

    for model_ref in provider_chain.iter().take(if disable_fallback {
        1
    } else {
        provider_chain.len()
    }) {
        match build_candidate(config, model_ref) {
            Ok(candidate) => {
                if !candidates
                    .iter()
                    .any(|existing: &ProviderCandidate| existing.model_ref == candidate.model_ref)
                {
                    candidates.push(candidate);
                }
            }
            Err(err) => errors.push(format!("{}: {err}", model_ref.as_string())),
        }
    }

    match candidates.len() {
        0 => Err(anyhow!(
            "no available providers for configured model chain: {}",
            errors.join("; ")
        )),
        _ => Ok(Arc::new(FallbackProvider { candidates })),
    }
}

pub(crate) fn build_candidate(
    config: &AppConfig,
    model_ref: &ModelRef,
) -> Result<ProviderCandidate> {
    let provider_config = config.providers.get(&model_ref.provider).ok_or_else(|| {
        anyhow!(
            "unknown provider {}; configure providers.{}",
            model_ref.provider.as_str(),
            model_ref.provider.as_str()
        )
    })?;
    let resolved_policy = resolved_model_policy_for_candidate(config, model_ref);
    let openai_compaction_policy = OpenAiCompactionPolicy {
        trigger_input_tokens: resolved_policy.compaction_trigger_estimated_tokens as u64,
    };
    let provider: Arc<dyn AgentProvider> = match provider_config.transport {
        ProviderTransportKind::OpenAiCodexResponses => Arc::new(
            OpenAiCodexProvider::from_runtime_config_with_compaction_policy(
                provider_config,
                &model_ref.model,
                config.runtime_max_output_tokens,
                &config.home_dir,
                openai_compaction_policy,
            )?,
        ),
        ProviderTransportKind::OpenAiResponses => {
            Arc::new(OpenAiProvider::from_runtime_config_with_compaction_policy(
                provider_config,
                &model_ref.model,
                config.runtime_max_output_tokens,
                &config.home_dir,
                openai_compaction_policy,
            )?)
        }
        ProviderTransportKind::AnthropicMessages => {
            Arc::new(AnthropicProvider::from_runtime_config(
                provider_config,
                &model_ref.model,
                config.runtime_max_output_tokens,
                &config.home_dir,
            )?)
        }
        ProviderTransportKind::OpenAiChatCompletions => {
            Arc::new(OpenAiChatCompletionsProvider::from_runtime_config(
                provider_config,
                &model_ref.model,
                config.runtime_max_output_tokens,
                &config.home_dir,
            )?)
        }
    };
    Ok(ProviderCandidate {
        model_ref: model_ref.as_string(),
        provider_name: model_ref.provider.as_str().to_string(),
        provider,
    })
}

fn resolved_model_policy_for_candidate(
    config: &AppConfig,
    model_ref: &ModelRef,
) -> crate::model_catalog::ResolvedRuntimeModelPolicy {
    let base_context_config = ContextConfig {
        recent_messages: config.context_window_messages,
        recent_briefs: config.context_window_briefs,
        compaction_trigger_messages: config.compaction_trigger_messages,
        compaction_keep_recent_messages: config.compaction_keep_recent_messages,
        prompt_budget_estimated_tokens: config.prompt_budget_estimated_tokens,
        compaction_trigger_estimated_tokens: config.compaction_trigger_estimated_tokens,
        compaction_keep_recent_estimated_tokens: config.compaction_keep_recent_estimated_tokens,
        recent_episode_candidates: config.recent_episode_candidates,
        max_relevant_episodes: config.max_relevant_episodes,
    };
    BuiltInModelCatalog::default().resolve_policy(
        model_ref,
        &config.validated_model_overrides,
        config.validated_unknown_model_fallback.as_ref(),
        &base_context_config,
        config.runtime_max_output_tokens,
    )
}