Struct ObservabilityConfig 

#[non_exhaustive]
pub struct ObservabilityConfig {
    pub log_level: String,
    pub log_format: String,
    pub audit_log_path: Option<PathBuf>,
    pub log_request_headers: bool,
    pub metrics_enabled: bool,
    pub metrics_bind: String,
    pub log_plaintext_oauth_tokens: bool,
    pub log_oauth_claim_values: bool,
    pub log_tool_call_arguments: bool,
    pub log_upstream_error_bodies: bool,
}

Observability settings (reusable across MCP projects).

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

log_level: String

tracing log level / env filter string (e.g. info,rmcp_server_kit=debug).

log_format: String

Log output format: json, pretty, or text (default: pretty).

audit_log_path: Option<PathBuf>

Optional path to an append-only audit log file.

log_request_headers: bool

Emit inbound HTTP request headers at DEBUG level in transport logs. Sensitive headers remain redacted when enabled.

metrics_enabled: bool

Enable the Prometheus metrics endpoint.

metrics_bind: String

Bind address for the Prometheus metrics listener.

log_plaintext_oauth_tokens: bool

Log OAuth access tokens in plaintext. Defaults to redacted; enabling writes secrets to logs and is for local debugging only. Process-wide, not per-server.

log_oauth_claim_values: bool

Log OAuth claim values in plaintext. Defaults to redacted; enabling writes secrets to logs and is for local debugging only. Process-wide, not per-server.

log_tool_call_arguments: bool

Log tool-call arguments and identity fields in plaintext. Defaults to redacted; enabling writes secrets to logs and is for local debugging only. Process-wide, not per-server.

log_upstream_error_bodies: bool

Log the error_description an authorization server returns on a failed RFC 8693 token exchange. Defaults to redacted; the value is free-form upstream text that may reflect request parameters back. Process-wide, not per-server.

Implementations

impl ObservabilityConfig

pub fn apply_env_overrides( &mut self, ) -> Result<Vec<EnvOverride>, RmcpServerKitError>

Applies RMCP_SERVER_KIT__OBSERVABILITY__* environment overrides.

This method is opt-in and only mutates this struct; it does not update tracing subscribers or server metrics configuration by itself.

Errors

Returns RmcpServerKitError::Config when a boolean override cannot be parsed.

Examples

The full config-file pipeline lives in examples/config_file_server.rs.

use rmcp_server_kit::config::ObservabilityConfig;

let mut observability = ObservabilityConfig::default();
// Do not set process env in doctests: rustdoc examples share a process.
let report = observability.apply_env_overrides()?;
let _report_shape: Vec<(&str, &str, Option<&str>)> = report
    .iter()
    .map(|entry| {
        (
            entry.env_var.as_str(),
            entry.target_field.as_str(),
            entry.value.as_deref(),
        )
    })
    .collect();

Trait Implementations

impl Debug for ObservabilityConfig

Hand-written so audit_log_path never reaches a log.

SECURITY: the audit log’s location is operational metadata an attacker can use to find or tamper with the audit trail. Presence is still reported; only the path is withheld. observability_config_debug_lists_every_field fails if a field is added without being rendered here.

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

Formats the value using the given formatter.

impl Default for ObservabilityConfig

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ObservabilityConfig

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.