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aibrahim-oai merged 2 commits into from
Jun 25, 2026
Merged

Report MCP error codes with server attribution #29969

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ed84076
Report MCP server error codes in telemetry
aibrahim-oai Jun 25, 2026
5bc28d0
Fix MCP metric tag expectation
aibrahim-oai Jun 25, 2026
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55 changes: 25 additions & 30 deletions codex-rs/core/src/mcp_tool_call.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -92,9 +92,7 @@ use url::Url;

mod telemetry;

use telemetry::MCP_CALL_COUNT_METRIC;
use telemetry::McpCallMetricOutcome;
use telemetry::McpErrorCodeSource;
use telemetry::emit_mcp_call_metrics;
use telemetry::mcp_call_metric_outcome;
use telemetry::record_mcp_call_outcome_span_telemetry;
Expand Down Expand Up @@ -182,6 +180,13 @@ pub(crate) async fn handle_mcp_tool_call(
.await
};

let connector_id = metadata
.as_ref()
.and_then(|metadata| metadata.connector_id.clone());
let connector_name = metadata
.as_ref()
.and_then(|metadata| metadata.connector_name.clone());

if server == CODEX_APPS_MCP_SERVER_NAME && !app_tool_policy.enabled {
let result = notify_mcp_tool_call_skip(
sess.as_ref(),
Expand All @@ -194,24 +199,22 @@ pub(crate) async fn handle_mcp_tool_call(
)
.await;
let status = if result.is_ok() { "ok" } else { "error" };
turn_context.session_telemetry.counter(
MCP_CALL_COUNT_METRIC,
/*inc*/ 1,
&[("status", status)],
let outcome = McpCallMetricOutcome::from_status(status);
emit_mcp_call_metrics(
turn_context.as_ref(),
&outcome,
&server,
&tool_name,
connector_id.as_deref(),
connector_name.as_deref(),
/*duration*/ None,
);
return HandledMcpToolCall {
result: CallToolResult::from_result(result),
tool_input: arguments_value
.unwrap_or_else(|| JsonValue::Object(serde_json::Map::new())),
};
}
let connector_id = metadata
.as_ref()
.and_then(|metadata| metadata.connector_id.clone());
let connector_name = metadata
.as_ref()
.and_then(|metadata| metadata.connector_name.clone());

notify_mcp_tool_call_started(
sess.as_ref(),
turn_context.as_ref(),
Expand Down Expand Up @@ -279,6 +282,7 @@ pub(crate) async fn handle_mcp_tool_call(
emit_mcp_call_metrics(
turn_context.as_ref(),
&outcome,
&server,
&tool_name,
connector_id.as_deref(),
connector_name.as_deref(),
Expand Down Expand Up @@ -348,17 +352,11 @@ async fn handle_approved_mcp_tool_call(
let arguments_value = invocation.arguments.clone();
let connector_id = metadata.and_then(|metadata| metadata.connector_id.as_deref());
let connector_name = metadata.and_then(|metadata| metadata.connector_name.as_deref());
let (server_origin, error_code_source) = {
let server_origin = {
let mcp_connection_manager = sess.services.mcp_connection_manager.load_full();
let server_origin = mcp_connection_manager
mcp_connection_manager
.server_origin(&server)
.map(str::to_string);
let error_code_source = if mcp_connection_manager.is_host_owned_codex_apps_server(&server) {
McpErrorCodeSource::HostedPluginService
} else {
McpErrorCodeSource::Untrusted
};
(server_origin, error_code_source)
.map(str::to_string)
};

let start = Instant::now();
Expand Down Expand Up @@ -392,7 +390,7 @@ async fn handle_approved_mcp_tool_call(
.await
}
.await;
record_mcp_result_span_telemetry(&Span::current(), &result, error_code_source);
record_mcp_result_span_telemetry(&Span::current(), &result);
result
}
.instrument(mcp_tool_call_span(
Expand Down Expand Up @@ -424,10 +422,11 @@ async fn handle_approved_mcp_tool_call(
.await;
maybe_track_codex_app_used(sess, turn_context, &server, &tool_name).await;

let outcome = mcp_call_metric_outcome(&result, error_code_source);
let outcome = mcp_call_metric_outcome(&result);
emit_mcp_call_metrics(
turn_context,
&outcome,
&server,
&tool_name,
connector_id,
connector_name,
Expand Down Expand Up @@ -501,12 +500,8 @@ fn record_server_fields(span: &Span, url: Option<&str>) {
}
}

fn record_mcp_result_span_telemetry(
span: &Span,
result: &Result<CallToolResult, String>,
error_code_source: McpErrorCodeSource,
) {
record_mcp_call_outcome_span_telemetry(span, result, error_code_source);
fn record_mcp_result_span_telemetry(span: &Span, result: &Result<CallToolResult, String>) {
record_mcp_call_outcome_span_telemetry(span, result);

let Some(span_telemetry) = result
.as_ref()
Expand Down
79 changes: 38 additions & 41 deletions codex-rs/core/src/mcp_tool_call/telemetry.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ use codex_protocol::mcp::CallToolResult;
use serde_json::Value as JsonValue;
use tracing::Span;

pub(super) const MCP_CALL_COUNT_METRIC: &str = "codex.mcp.call";
const MCP_CALL_COUNT_METRIC: &str = "codex.mcp.call";
const MCP_CALL_DURATION_METRIC: &str = "codex.mcp.call.duration_ms";
const MCP_CALL_ERROR_COUNT_METRIC: &str = "codex.mcp.call.error";
// No CallToolResult was received. This includes request setup, transport, timeout, protocol, and
Expand Down Expand Up @@ -37,21 +37,22 @@ impl McpCallMetricOutcome {
}
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub(super) enum McpErrorCodeSource {
HostedPluginService,
Untrusted,
}

pub(super) fn emit_mcp_call_metrics(
turn_context: &TurnContext,
outcome: &McpCallMetricOutcome,
server_name: &str,
tool_name: &str,
connector_id: Option<&str>,
connector_name: Option<&str>,
duration: Option<Duration>,
) {
let tags = mcp_call_metric_tags(outcome.status, tool_name, connector_id, connector_name);
let tags = mcp_call_metric_tags(
outcome.status,
server_name,
tool_name,
connector_id,
connector_name,
);
let tag_refs: Vec<(&str, &str)> = tags
.iter()
.map(|(key, value)| (*key, value.as_str()))
Expand Down Expand Up @@ -87,12 +88,14 @@ pub(super) fn emit_mcp_call_metrics(

fn mcp_call_metric_tags(
status: &str,
server_name: &str,
tool_name: &str,
connector_id: Option<&str>,
connector_name: Option<&str>,
) -> Vec<(&'static str, String)> {
let mut tags = vec![
("status", sanitize_metric_tag_value(status)),
("server", sanitize_metric_tag_value(server_name)),
("tool", sanitize_metric_tag_value(tool_name)),
];
if let Some(connector_id) = connector_id.filter(|connector_id| !connector_id.is_empty()) {
Expand All @@ -107,40 +110,35 @@ fn mcp_call_metric_tags(

pub(super) fn mcp_call_metric_outcome(
result: &Result<CallToolResult, String>,
error_code_source: McpErrorCodeSource,
) -> McpCallMetricOutcome {
match result {
Ok(result) if result.is_error.unwrap_or(false) => {
let error_code = if error_code_source == McpErrorCodeSource::HostedPluginService {
result
.structured_content
.as_ref()
.and_then(JsonValue::as_object)
.and_then(|structured_content| structured_content.get("error_code"))
.and_then(JsonValue::as_str)
.filter(|error_code| !error_code.is_empty())
.or_else(|| {
result
.meta
.as_ref()
.and_then(JsonValue::as_object)
.and_then(|meta| meta.get(MCP_TOOL_CODEX_APPS_META_KEY))
.and_then(JsonValue::as_object)
.and_then(|codex_apps| codex_apps.get("connector_auth_failure"))
.and_then(JsonValue::as_object)
.filter(|auth_failure| {
auth_failure
.get("is_auth_failure")
.and_then(JsonValue::as_bool)
== Some(true)
})
.and_then(|auth_failure| auth_failure.get("error_code"))
.and_then(JsonValue::as_str)
.filter(|error_code| !error_code.is_empty())
})
} else {
None
};
let error_code = result
.structured_content
.as_ref()
.and_then(JsonValue::as_object)
.and_then(|structured_content| structured_content.get("error_code"))
.and_then(JsonValue::as_str)
.filter(|error_code| !error_code.is_empty())
.or_else(|| {
result
.meta
.as_ref()
.and_then(JsonValue::as_object)
.and_then(|meta| meta.get(MCP_TOOL_CODEX_APPS_META_KEY))
.and_then(JsonValue::as_object)
.and_then(|codex_apps| codex_apps.get("connector_auth_failure"))
.and_then(JsonValue::as_object)
.filter(|auth_failure| {
auth_failure
.get("is_auth_failure")
.and_then(JsonValue::as_bool)
== Some(true)
})
.and_then(|auth_failure| auth_failure.get("error_code"))
.and_then(JsonValue::as_str)
.filter(|error_code| !error_code.is_empty())
});
let error_code: String = error_code
.unwrap_or(MCP_CALL_ERROR_CODE_UNKNOWN)
.chars()
Expand All @@ -164,9 +162,8 @@ pub(super) fn mcp_call_metric_outcome(
pub(super) fn record_mcp_call_outcome_span_telemetry(
span: &Span,
result: &Result<CallToolResult, String>,
error_code_source: McpErrorCodeSource,
) {
let outcome = mcp_call_metric_outcome(result, error_code_source);
let outcome = mcp_call_metric_outcome(result);
let (Some(error_type), Some(error_code)) = (outcome.error_type, outcome.error_code) else {
return;
};
Expand Down
59 changes: 35 additions & 24 deletions codex-rs/core/src/mcp_tool_call/telemetry_tests.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -14,39 +14,50 @@ fn metric_call_tool_result(
}

#[test]
fn mcp_call_metric_outcome_distinguishes_request_and_tool_errors() {
fn mcp_call_metric_tags_include_server_name() {
assert_eq!(
mcp_call_metric_outcome(
&Ok(metric_call_tool_result(
/*is_error*/ false, /*structured_content*/ None,
)),
McpErrorCodeSource::HostedPluginService,
mcp_call_metric_tags(
"error",
"docs server",
"search docs",
Some("connector/docs"),
Some("Docs connector"),
),
vec![
("status", "error".to_string()),
("server", "docs_server".to_string()),
("tool", "search_docs".to_string()),
("connector_id", "connector/docs".to_string()),
("connector_name", "Docs_connector".to_string()),
],
);
}

#[test]
fn mcp_call_metric_outcome_distinguishes_request_and_tool_errors() {
assert_eq!(
mcp_call_metric_outcome(&Ok(metric_call_tool_result(
/*is_error*/ false, /*structured_content*/ None,
)),),
McpCallMetricOutcome {
status: "ok",
error_type: None,
error_code: None,
}
);
assert_eq!(
mcp_call_metric_outcome(
&Ok(metric_call_tool_result(
/*is_error*/ true,
Some(serde_json::json!({"error_code": "RATE_LIMITED"})),
)),
McpErrorCodeSource::HostedPluginService,
),
mcp_call_metric_outcome(&Ok(metric_call_tool_result(
/*is_error*/ true,
Some(serde_json::json!({"error_code": "RATE_LIMITED"})),
)),),
McpCallMetricOutcome {
status: "error",
error_type: Some(MCP_CALL_ERROR_TYPE_TOOL_RESULT),
error_code: Some("RATE_LIMITED".to_string()),
}
);
assert_eq!(
mcp_call_metric_outcome(
&Err("connection closed".to_string()),
McpErrorCodeSource::HostedPluginService,
),
mcp_call_metric_outcome(&Err("connection closed".to_string())),
McpCallMetricOutcome {
status: "error",
error_type: Some(MCP_CALL_ERROR_TYPE_MCP_REQUEST),
Expand All @@ -56,24 +67,24 @@ fn mcp_call_metric_outcome_distinguishes_request_and_tool_errors() {
}

#[test]
fn mcp_call_metric_outcome_ignores_untrusted_tool_error_codes() {
fn mcp_call_metric_outcome_reports_server_tool_error_codes() {
let result = Ok(metric_call_tool_result(
/*is_error*/ true,
Some(serde_json::json!({"error_code": "arbitrary-user-value"})),
));

assert_eq!(
mcp_call_metric_outcome(&result, McpErrorCodeSource::Untrusted),
mcp_call_metric_outcome(&result),
McpCallMetricOutcome {
status: "error",
error_type: Some(MCP_CALL_ERROR_TYPE_TOOL_RESULT),
error_code: Some(MCP_CALL_ERROR_CODE_UNKNOWN.to_string()),
error_code: Some("arbitrary-user-value".to_string()),
}
);
}

#[test]
fn mcp_call_metric_outcome_reads_hosted_auth_error_code_from_meta() {
fn mcp_call_metric_outcome_reads_auth_error_code_from_meta() {
let result = CallToolResult {
content: Vec::new(),
structured_content: None,
Expand All @@ -89,7 +100,7 @@ fn mcp_call_metric_outcome_reads_hosted_auth_error_code_from_meta() {
};

assert_eq!(
mcp_call_metric_outcome(&Ok(result), McpErrorCodeSource::HostedPluginService),
mcp_call_metric_outcome(&Ok(result)),
McpCallMetricOutcome {
status: "error",
error_type: Some(MCP_CALL_ERROR_TYPE_TOOL_RESULT),
Expand All @@ -99,15 +110,15 @@ fn mcp_call_metric_outcome_reads_hosted_auth_error_code_from_meta() {
}

#[test]
fn mcp_call_metric_outcome_bounds_and_sanitizes_hosted_error_code() {
fn mcp_call_metric_outcome_bounds_and_sanitizes_error_code() {
let raw_error_code = format!("BAD CODE {}", "x".repeat(300));
let result = Ok(metric_call_tool_result(
/*is_error*/ true,
Some(serde_json::json!({"error_code": raw_error_code})),
));

assert_eq!(
mcp_call_metric_outcome(&result, McpErrorCodeSource::HostedPluginService),
mcp_call_metric_outcome(&result),
McpCallMetricOutcome {
status: "error",
error_type: Some(MCP_CALL_ERROR_TYPE_TOOL_RESULT),
Expand Down
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