task_graph_mcp/
error.rs

1//! Structured error and warning types for tool responses.
2
3use serde::Serialize;
4use std::fmt;
5
6/// Error codes for programmatic error handling.
7#[derive(Debug, Clone, Copy, Serialize, PartialEq, Eq)]
8#[serde(rename_all = "SCREAMING_SNAKE_CASE")]
9pub enum ErrorCode {
10    // Validation errors (4xx-like)
11    MissingRequiredField,
12    InvalidFieldValue,
13    InvalidState,
14    InvalidPath,
15    InvalidPrefix,
16
17    // Not found errors
18    AgentNotFound,
19    TaskNotFound,
20    FileNotFound,
21    AttachmentNotFound,
22
23    // Conflict errors
24    AlreadyClaimed,
25    AlreadyExists,
26    DependencyCycle,
27    TagMismatch,
28    NotOwner,
29    DependencyNotSatisfied,
30    GatesNotSatisfied,
31
32    // Internal errors
33    DatabaseError,
34    InternalError,
35    UnknownTool,
36}
37
38/// Warning codes for non-fatal issues.
39#[derive(Debug, Clone, Copy, Serialize, PartialEq, Eq)]
40#[serde(rename_all = "SCREAMING_SNAKE_CASE")]
41pub enum WarningCode {
42    /// Referenced task does not exist (link skipped)
43    TaskNotFound,
44    /// Referenced dependency does not exist (link skipped)
45    DependencyNotFound,
46    /// Tag is not in the known tags list
47    UnknownTag,
48    /// Phase is not in the known phases list
49    UnknownPhase,
50    /// Duplicate operation (no-op)
51    Duplicate,
52    /// Deprecated feature or parameter
53    Deprecated,
54}
55
56/// A warning about a non-fatal issue in a tool operation.
57#[derive(Debug, Clone, Serialize)]
58pub struct ToolWarning {
59    pub code: WarningCode,
60    pub message: String,
61    #[serde(skip_serializing_if = "Option::is_none")]
62    pub field: Option<String>,
63    #[serde(skip_serializing_if = "Option::is_none")]
64    pub value: Option<String>,
65}
66
67impl ToolWarning {
68    pub fn new(code: WarningCode, message: impl Into<String>) -> Self {
69        Self {
70            code,
71            message: message.into(),
72            field: None,
73            value: None,
74        }
75    }
76
77    pub fn with_field(mut self, field: impl Into<String>) -> Self {
78        self.field = Some(field.into());
79        self
80    }
81
82    pub fn with_value(mut self, value: impl Into<String>) -> Self {
83        self.value = Some(value.into());
84        self
85    }
86
87    // Convenience constructors
88
89    pub fn task_not_found(task_id: &str) -> Self {
90        Self::new(
91            WarningCode::TaskNotFound,
92            format!("Task '{}' not found, skipped", task_id),
93        )
94        .with_value(task_id)
95    }
96
97    pub fn dependency_not_found(task_id: &str, field: &str) -> Self {
98        Self::new(
99            WarningCode::DependencyNotFound,
100            format!("Dependency target '{}' not found, link skipped", task_id),
101        )
102        .with_field(field)
103        .with_value(task_id)
104    }
105
106    pub fn unknown_tag(tag: &str) -> Self {
107        Self::new(
108            WarningCode::UnknownTag,
109            format!("Tag '{}' is not in known tags list", tag),
110        )
111        .with_value(tag)
112    }
113
114    pub fn unknown_phase(phase: &str) -> Self {
115        Self::new(
116            WarningCode::UnknownPhase,
117            format!("Phase '{}' is not in known phases list", phase),
118        )
119        .with_value(phase)
120    }
121
122    pub fn duplicate(what: &str) -> Self {
123        Self::new(WarningCode::Duplicate, format!("{} already exists", what))
124    }
125
126    pub fn deprecated(feature: &str, alternative: &str) -> Self {
127        Self::new(
128            WarningCode::Deprecated,
129            format!("'{}' is deprecated, use '{}' instead", feature, alternative),
130        )
131    }
132}
133
134impl fmt::Display for ToolWarning {
135    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
136        write!(f, "{}", self.message)
137    }
138}
139
140/// Structured error for tool responses.
141#[derive(Debug, Serialize)]
142pub struct ToolError {
143    pub code: ErrorCode,
144    pub message: String,
145    #[serde(skip_serializing_if = "Option::is_none")]
146    pub field: Option<String>,
147    #[serde(skip_serializing_if = "Option::is_none")]
148    pub details: Option<String>,
149}
150
151impl ToolError {
152    pub fn new(code: ErrorCode, message: impl Into<String>) -> Self {
153        Self {
154            code,
155            message: message.into(),
156            field: None,
157            details: None,
158        }
159    }
160
161    pub fn with_field(mut self, field: impl Into<String>) -> Self {
162        self.field = Some(field.into());
163        self
164    }
165
166    pub fn with_details(mut self, details: impl Into<String>) -> Self {
167        self.details = Some(details.into());
168        self
169    }
170
171    // Convenience constructors
172
173    pub fn missing_field(field: &str) -> Self {
174        Self::new(
175            ErrorCode::MissingRequiredField,
176            format!("{} is required", field),
177        )
178        .with_field(field)
179    }
180
181    pub fn invalid_value(field: &str, reason: &str) -> Self {
182        Self::new(ErrorCode::InvalidFieldValue, reason).with_field(field)
183    }
184
185    pub fn agent_not_found(agent_id: &str) -> Self {
186        Self::new(
187            ErrorCode::AgentNotFound,
188            format!("Agent not found: {}", agent_id),
189        )
190    }
191
192    pub fn task_not_found(task_id: &str) -> Self {
193        Self::new(
194            ErrorCode::TaskNotFound,
195            format!("Task not found: {}", task_id),
196        )
197    }
198
199    pub fn already_claimed(task_id: &str, owner: &str) -> Self {
200        Self::new(
201            ErrorCode::AlreadyClaimed,
202            format!("Task {} already claimed by {}", task_id, owner),
203        )
204    }
205
206    pub fn not_owner(task_id: &str, agent_id: &str) -> Self {
207        Self::new(
208            ErrorCode::NotOwner,
209            format!("Agent {} does not own task {}", agent_id, task_id),
210        )
211    }
212
213    pub fn dependency_cycle(blocker: &str, blocked: &str) -> Self {
214        Self::new(
215            ErrorCode::DependencyCycle,
216            format!(
217                "Adding dependency {} -> {} would create a cycle",
218                blocker, blocked
219            ),
220        )
221    }
222
223    pub fn tag_mismatch(missing: &str) -> Self {
224        Self::new(
225            ErrorCode::TagMismatch,
226            format!("Agent missing required tag(s): {}", missing),
227        )
228    }
229
230    pub fn deps_not_satisfied(blockers: &[String]) -> Self {
231        Self::new(
232            ErrorCode::DependencyNotSatisfied,
233            format!("Task blocked by: {}", blockers.join(", ")),
234        )
235    }
236
237    pub fn gates_not_satisfied(status: &str, gates: &[String]) -> Self {
238        Self::new(
239            ErrorCode::GatesNotSatisfied,
240            format!(
241                "Cannot exit '{}': unsatisfied gates: {}",
242                status,
243                gates.join(", ")
244            ),
245        )
246    }
247
248    pub fn invalid_path(path: &str, reason: &str) -> Self {
249        Self::new(
250            ErrorCode::InvalidPath,
251            format!("Invalid path '{}': {}", path, reason),
252        )
253    }
254
255    pub fn prefix_not_lowercase(prefix: &str) -> Self {
256        Self::new(
257            ErrorCode::InvalidPrefix,
258            format!("Path prefix '{}' must be lowercase", prefix),
259        )
260    }
261
262    pub fn unknown_prefix(prefix: &str) -> Self {
263        Self::new(
264            ErrorCode::InvalidPrefix,
265            format!("Unknown path prefix: {}", prefix),
266        )
267    }
268
269    pub fn sandbox_escape(path: &str, root: &str) -> Self {
270        Self::new(
271            ErrorCode::InvalidPath,
272            format!("Path '{}' escapes sandbox root '{}'", path, root),
273        )
274    }
275
276    pub fn database(err: impl fmt::Display) -> Self {
277        Self::new(ErrorCode::DatabaseError, err.to_string())
278    }
279
280    pub fn internal(err: impl fmt::Display) -> Self {
281        Self::new(ErrorCode::InternalError, err.to_string())
282    }
283
284    pub fn unknown_tool(name: &str) -> Self {
285        Self::new(ErrorCode::UnknownTool, format!("Unknown tool: {}", name))
286    }
287}
288
289impl fmt::Display for ToolError {
290    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
291        write!(f, "{}", self.message)
292    }
293}
294
295impl std::error::Error for ToolError {}
296
297// Allow using ? with anyhow errors by converting them
298impl From<anyhow::Error> for ToolError {
299    fn from(err: anyhow::Error) -> Self {
300        // Try to downcast to ToolError first
301        match err.downcast::<ToolError>() {
302            Ok(tool_err) => tool_err,
303            Err(err) => ToolError::internal(err),
304        }
305    }
306}
307
308/// Result type for tool operations.
309pub type ToolResult<T> = std::result::Result<T, ToolError>;
task_graph_mcp/error.rs

task_graph_mcp/
error.rs
