arbiter_session/
error.rs

1use thiserror::Error;
2use uuid::Uuid;
3
4/// Errors from session operations.
5///
6/// Display impls are intentionally opaque — they appear in
7/// HTTP error responses sent to agents. Internal fields are preserved for
8/// structured logging via Debug. Previously, Display exposed budget limits,
9/// rate limit values, tool names, and session caps to untrusted agents.
10#[derive(Debug, Error)]
11pub enum SessionError {
12    /// The referenced session does not exist.
13    #[error("session not found")]
14    NotFound(Uuid),
15
16    /// The session has expired (time limit exceeded).
17    #[error("session expired")]
18    Expired(Uuid),
19
20    /// The session's call budget has been exhausted.
21    #[error("session budget exceeded")]
22    BudgetExceeded {
23        session_id: Uuid,
24        limit: u64,
25        used: u64,
26    },
27
28    /// The requested tool is not in the session's authorized set.
29    #[error("tool not authorized in session")]
30    ToolNotAuthorized { session_id: Uuid, tool: String },
31
32    /// The session has already been closed.
33    #[error("session already closed")]
34    AlreadyClosed(Uuid),
35
36    /// The session's per-minute rate limit has been exceeded.
37    #[error("session rate limit exceeded")]
38    RateLimited {
39        session_id: Uuid,
40        limit_per_minute: u64,
41    },
42
43    /// The presenting agent does not match the session's bound agent.
44    #[error("agent mismatch")]
45    AgentMismatch {
46        session_id: Uuid,
47        expected: Uuid,
48        actual: Uuid,
49    },
50
51    /// Storage write-through failed after updating cache.
52    /// The session state in the cache is ahead of durable storage.
53    #[error("storage write-through failed")]
54    StorageWriteThrough { session_id: Uuid, detail: String },
55
56    /// The agent has reached the maximum number of concurrent active sessions.
57    ///
58    /// P0: Per-agent session cap to prevent session multiplication attacks.
59    #[error("too many concurrent sessions")]
60    TooManySessions {
61        agent_id: String,
62        max: u64,
63        current: u64,
64    },
65}
arbiter_session/error.rs

arbiter_session/
error.rs
