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//! Typed call/result pairing receipts for the LLM transcript sidecar.
//!
//! # Why the transcript needs them
//!
//! Reconstructing "which tool result answers which tool call" from the
//! recorded turns alone does not work on every channel.
//!
//! On the native channel the provider gives each call an id and the result
//! message carries it back, so the pair is visible. On the text channel there
//! is no such id: the model writes an inline `<tool_call>` block, and the
//! result is served back as an ordinary `role: "user"` echo with no identity
//! anywhere on it. A consumer left to pair those by position is guessing —
//! and that is precisely how a generic aggregate placeholder ends up looking
//! like a tool result.
//!
//! `provider_call_response.parsed_tool_calls` cannot stand in either. It is
//! written when the provider replies, before the loop parses the turn, and on
//! a text-channel run it re-parses the same text against its own counter. Its
//! synthetic `tc_N` ids are a parallel id space that no result ever answers.
//!
//! So the two moments that actually know the answer record it: dispatch knows
//! the id a call ran under, and injection knows the message index a result
//! landed at. Together they make the sidecar self-describing on every channel.
//!
//! # Observability-only
//!
//! Like `resolved_dispatch`, nothing recorded here re-enters request
//! construction. The model's next-turn payload is byte-identical with or
//! without these events.
use crate::orchestration::{TOOL_CALL_RECEIPT_VERSION, TOOL_RESULT_RECEIPT_VERSION};
use crate::value::VmValue;
use serde::Serialize;
const SESSION_MESSAGE_FACTS_KEY: &str = "_harn";
#[derive(Serialize)]
#[serde(tag = "kind", rename_all = "snake_case")]
enum SessionMessageFacts {
Assistant {
tool_calls: Vec<serde_json::Value>,
},
ToolResult {
tool_call_id: String,
tool_name: String,
outcome: ToolResultOutcome,
#[serde(skip_serializing_if = "Option::is_none")]
data: Option<serde_json::Value>,
},
}
#[derive(Serialize)]
#[serde(rename_all = "snake_case")]
enum ToolResultOutcome {
Ok,
Error,
}
fn attach_session_message_facts(message: VmValue, facts: &SessionMessageFacts) -> VmValue {
let Some(existing) = message.as_dict() else {
return message;
};
let mut enriched = existing.clone();
let encoded = serde_json::to_value(facts).expect("session message facts must serialize");
enriched.insert(
crate::value::intern_key(SESSION_MESSAGE_FACTS_KEY),
crate::stdlib::json_to_vm_value(&encoded),
);
VmValue::dict(enriched)
}
/// Attach provider-neutral parsed call facts to a durable assistant message.
/// The unified post-parse `tool_calls` list is authoritative; direct host
/// embeddings that supply only `native_tool_calls` retain those as a fallback.
/// Provider adapters strip `_harn` before egress, so transcript consumers read
/// one lifecycle shape without altering provider-visible history.
pub(crate) fn attach_assistant_facts(message: VmValue, llm_result: &VmValue) -> VmValue {
let tool_calls = ["tool_calls", "native_tool_calls"]
.iter()
.find_map(|key| {
llm_result
.as_dict()
.and_then(|result| result.get(*key))
.and_then(|value| match value {
VmValue::List(items) if !items.is_empty() => Some(
items
.iter()
.map(crate::llm::helpers::vm_value_to_json)
.collect::<Vec<_>>(),
),
_ => None,
})
})
.unwrap_or_default();
attach_session_message_facts(message, &SessionMessageFacts::Assistant { tool_calls })
}
/// Attach the dispatch-owned result identity and outcome to a durable result
/// message on every provider/tool-format channel.
pub(crate) fn attach_tool_result_facts(
message: VmValue,
tool_call_id: &str,
tool_name: &str,
ok: bool,
data: Option<&VmValue>,
) -> VmValue {
attach_session_message_facts(
message,
&SessionMessageFacts::ToolResult {
tool_call_id: tool_call_id.to_string(),
tool_name: tool_name.to_string(),
outcome: if ok {
ToolResultOutcome::Ok
} else {
ToolResultOutcome::Error
},
data: data.map(crate::llm::helpers::vm_value_to_json),
},
)
}
/// Record the calls a batch is about to dispatch, with the ids their results
/// will answer under.
///
/// Emitted before dispatch, so the receipts for one assistant turn appear in
/// the order the calls were requested even when the batch runs them
/// concurrently.
pub(crate) fn emit_tool_call_receipts(calls: &[VmValue]) {
let Some(session_id) = crate::agent_sessions::current_session_id() else {
return;
};
// The calls were parsed from the message just before the next slot, i.e.
// the assistant turn this batch answers.
let Some(next_index) = crate::agent_sessions::next_message_index(&session_id) else {
return;
};
let assistant_message_index = next_index.saturating_sub(1);
for call in calls {
let call = crate::llm::helpers::vm_value_to_json(call);
let mut fields = serde_json::Map::new();
fields.insert(
"schema_version".to_string(),
serde_json::json!(TOOL_CALL_RECEIPT_VERSION),
);
fields.insert("session_id".to_string(), serde_json::json!(session_id));
fields.insert(
"assistant_message_index".to_string(),
serde_json::json!(assistant_message_index),
);
fields.insert(
"call_id".to_string(),
serde_json::json!(string_field(&call, &["id", "tool_call_id"])),
);
fields.insert(
"tool_name".to_string(),
serde_json::json!(string_field(&call, &["name", "tool_name"])),
);
fields.insert(
"arguments".to_string(),
call.get("arguments")
.or_else(|| call.get("tool_args"))
.cloned()
.unwrap_or_else(|| serde_json::Value::Object(serde_json::Map::new())),
);
crate::llm::append_observability_sidecar_entry("tool_call", fields);
}
}
/// Record which call the message just injected answers.
///
/// `message_index` is the index [`crate::agent_sessions::inject_message`]
/// returned, which binds the receipt to one exact message instead of to
/// whatever event happens to follow it.
pub(crate) fn emit_tool_result_receipt(
session_id: &str,
message_index: usize,
tool_call_id: &str,
tool_name: &str,
ok: bool,
tool_format: &str,
) {
let mut fields = serde_json::Map::new();
fields.insert(
"schema_version".to_string(),
serde_json::json!(TOOL_RESULT_RECEIPT_VERSION),
);
fields.insert("session_id".to_string(), serde_json::json!(session_id));
fields.insert(
"message_index".to_string(),
serde_json::json!(message_index),
);
fields.insert("call_id".to_string(), serde_json::json!(tool_call_id));
fields.insert("tool_name".to_string(), serde_json::json!(tool_name));
fields.insert("ok".to_string(), serde_json::json!(ok));
fields.insert("tool_format".to_string(), serde_json::json!(tool_format));
crate::llm::append_observability_sidecar_entry("tool_result", fields);
}
fn string_field(call: &serde_json::Value, keys: &[&str]) -> String {
keys.iter()
.find_map(|key| call.get(*key).and_then(serde_json::Value::as_str))
.unwrap_or_default()
.to_string()
}