api: move wire types and parsing to api module

Move FunctionCall, FunctionCallDelta, ToolCall, ToolCallDelta from
tools/mod.rs to api/types.rs — these are API wire format, not tool
definitions. Re-export from tools for existing callers.

Move parsing.rs to api/parsing.rs — leaked tool call parsing is API
plumbing.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/agent/api/mod.rs

@@ -6,6 +6,7 @@
 // Diagnostics: anomalies always logged to debug panel.
 // Set POC_DEBUG=1 for verbose per-turn logging.
 
+pub mod parsing;
 pub mod types;
 mod openai;
 
@@ -17,7 +18,8 @@ use std::time::{Duration, Instant};
 
 use tokio::sync::mpsc;
 
-use crate::agent::tools::{self as agent_tools, ToolCall, FunctionCall};
+use crate::agent::tools::{self as agent_tools};
+use types::{ToolCall, FunctionCall};
 use crate::user::ui_channel::{UiMessage, UiSender};
 
 /// A JoinHandle that aborts its task when dropped.
@@ -488,9 +490,9 @@ pub fn build_response_message(
     }
 
     // Check for leaked tool calls in content text.
-    let leaked = crate::agent::parsing::parse_leaked_tool_calls(&content);
+    let leaked = parsing::parse_leaked_tool_calls(&content);
     if !leaked.is_empty() {
-        let cleaned = crate::agent::parsing::strip_leaked_artifacts(&content);
+        let cleaned = parsing::strip_leaked_artifacts(&content);
         return Message {
             role: Role::Assistant,
             content: if cleaned.trim().is_empty() { None }

src/agent/api/parsing.rs

@@ -11,7 +11,7 @@
 // Also handles streaming artifacts: whitespace inside XML tags from
 // token boundaries, </think> tags, etc.
 
-use crate::agent::tools::{ToolCall, FunctionCall};
+use super::types::{ToolCall, FunctionCall};
 
 /// Parse leaked tool calls from response text.
 /// Looks for `<tool_call>...</tool_call>` blocks and tries both

src/agent/api/types.rs

@@ -9,7 +9,38 @@
 use chrono::Utc;
 use serde::{Deserialize, Serialize};
 
-use crate::agent::tools::{ToolCall, ToolCallDelta};
+/// Function call within a tool call — name + JSON arguments.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct FunctionCall {
+    pub name: String,
+    pub arguments: String,
+}
+
+/// Partial function call within a streaming delta.
+#[derive(Debug, Deserialize)]
+pub struct FunctionCallDelta {
+    pub name: Option<String>,
+    pub arguments: Option<String>,
+}
+
+/// A tool call requested by the model.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ToolCall {
+    pub id: String,
+    #[serde(rename = "type")]
+    pub call_type: String,
+    pub function: FunctionCall,
+}
+
+/// A partial tool call within a streaming delta.
+#[derive(Debug, Deserialize)]
+pub struct ToolCallDelta {
+    pub index: usize,
+    pub id: Option<String>,
+    #[serde(rename = "type")]
+    pub call_type: Option<String>,
+    pub function: Option<FunctionCallDelta>,
+}
 
 /// Message content — either plain text or an array of content parts
 /// (for multimodal messages with images). Serializes as a JSON string

src/agent/mod.rs

@@ -16,7 +16,6 @@
 pub mod api;
 pub mod context;
 pub mod oneshot;
-pub mod parsing;
 pub mod tools;
 pub mod training;
 
@@ -340,7 +339,7 @@ impl Agent {
                             tool_call_buf.push_str(&text);
                             if let Some(end) = tool_call_buf.find("</tool_call>") {
                                 let body = &tool_call_buf[..end];
-                                if let Some(call) = crate::agent::parsing::parse_tool_call_body(body) {
+                                if let Some(call) = crate::agent::api::parsing::parse_tool_call_body(body) {
                                     let args: serde_json::Value =
                                         serde_json::from_str(&call.function.arguments).unwrap_or_default();
                                     let args_summary = summarize_args(&call.function.name, &args);

src/agent/tools/mod.rs

@@ -20,7 +20,6 @@ mod control;
 mod vision;
 pub mod working_stack;
 
-use serde::{Serialize, Deserialize};
 use std::future::Future;
 use std::pin::Pin;
 use std::time::Instant;
@@ -57,40 +56,8 @@ impl Tool {
     }
 }
 
-/// Function call within a tool call — name + JSON arguments.
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct FunctionCall {
-    pub name: String,
-    pub arguments: String,
-}
-
-/// Partial function call within a streaming delta.
-#[derive(Debug, Deserialize)]
-pub struct FunctionCallDelta {
-    pub name: Option<String>,
-    pub arguments: Option<String>,
-}
-
-/// A tool call requested by the model.
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct ToolCall {
-    pub id: String,
-    #[serde(rename = "type")]
-    pub call_type: String,
-    pub function: FunctionCall,
-}
-
-/// A partial tool call within a streaming delta. The first chunk for a
-/// given tool call carries the id and function name; subsequent chunks
-/// carry argument fragments.
-#[derive(Debug, Deserialize)]
-pub struct ToolCallDelta {
-    pub index: usize,
-    pub id: Option<String>,
-    #[serde(rename = "type")]
-    pub call_type: Option<String>,
-    pub function: Option<FunctionCallDelta>,
-}
+// Re-export API wire types used by the agent turn loop
+pub use super::api::types::{FunctionCall, ToolCall, ToolCallDelta};
 
 /// A tool call in flight — metadata for TUI + JoinHandle for
 /// result collection and cancellation.