Enum LspError 

pub enum LspError {
    NoLspAvailable,
    Timeout {
        operation: String,
        timeout_ms: u64,
    },
    Protocol(String),
    ConnectionLost,
    UnsupportedCapability {
        capability: String,
    },
    Io(Error),
}

Errors that the LSP engine can produce.

Variants

NoLspAvailable

No language server is configured or available for this file type.

This is the expected error when Pathfinder is running without LSP support (i.e., in degraded mode). The calling tool handler should return a gracefully degraded response rather than propagating this error.

Timeout

The LSP server did not respond within the timeout window.

For initialization this is 30 seconds. For individual requests, it is configurable (default: 10s). Includes the operation name and timeout duration for structured logging.

Fields

operation: String

The JSON-RPC method that timed out.

timeout_ms: u64

The timeout that elapsed, in milliseconds.

Protocol(String)

The LSP server returned a JSON-RPC error response or sent malformed data.

The contained string is a human-readable description of the error, suitable for logging and agent-facing messages.

ConnectionLost

The LSP server process crashed or the connection was broken.

Triggers crash-recovery logic (exponential backoff, max 3 retries).

UnsupportedCapability

The LSP server is running but does not advertise the requested capability.

For example, a server that doesn’t implement Pull Diagnostics (LSP 3.17) will trigger this error for diagnostic queries. The tool handler should degrade gracefully and report the limitation to the caller.

Fields

capability: String

The LSP capability name (e.g., "diagnosticProvider").

Io(Error)

I/O error communicating with the LSP process.

Implementations

impl LspError

pub fn recovery_hint(&self) -> Option<String>

Returns an actionable recovery hint for the agent.

The hint tells agents what to do next — not just what went wrong. All variants return Some; agents should surface these in tool responses when validation or navigation degrades.

This is the LSP-layer equivalent of PathfinderError::hint().

Trait Implementations

impl Debug for LspError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for LspError

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for LspError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.