JuliusBrussee/caveman · error

telemetry attribute exceeds bytes

Error message

telemetry attribute %q exceeds %d bytes

What it means

SanitizeAttributes enforces per-value and total byte budgets for span attributes. This specific error fires when a single attribute value exceeds MaxAttributeValueBytes; a sibling error covers the aggregate total exceeding MaxAttributesBytes. It fails closed rather than truncating the value.

Solutions

1. Truncate the value before setting it (e.g. cap at 256 bytes with an ellipsis marker).
2. Store a digest/ID and keep the full payload in logs or object storage.
3. Split oversized payloads across dedicated log events rather than span attributes.
4. Audit instrumentation for places that serialize whole objects into attribute values.

Example fix

// before
attrs["http.response.body"] = string(fullResponseBody) // often > limit

// after
body := string(fullResponseBody)
if len(body) > 256 { body = body[:256] + "...[truncated]" }
attrs["http.response.body"] = body

for k, v := range attrs {
    if len(v) > maxAttrValueBytes /* mirror MaxAttributeValueBytes */ {
        attrs[k] = truncate(v, maxAttrValueBytes)
    }
}

sanitized, err := telemetry.SanitizeAttributes(raw)
if err != nil && strings.Contains(err.Error(), "exceeds") && strings.Contains(err.Error(), "bytes") {
    raw = truncateValues(raw, maxAttrValueBytes)
    sanitized, err = telemetry.SanitizeAttributes(raw)
}

When it happens

Trigger: Parse called on a span where attrs[key] has a byte length greater than MaxAttributeValueBytes — e.g. dumping an entire HTTP response body, stack trace, or serialized JSON payload into one attribute.

Common situations: Recording full request/response bodies as attributes; storing large exception stack traces; accidentally passing an entire config blob instead of a summary.

Understand the failure class

Background: payload too large / request exceeds maximum size: why libraries cap bytes and how to fix oversize payloads — this error's family across 50 libraries.

Related errors

• telemetry attribute key exceeds
• telemetry attributes exceed
• bounded
• cave_budget_release_exceeds_max
• eval evidence batch exceeds 1000 records

AI-assisted analysis of JuliusBrussee/caveman@3ee70a1026 (2026-09-20). Data as JSON: /api/errors/aa8808fee0d0a702. Report an issue: GitHub.

Appendix: source

Thrown at shared/platform/telemetry/span.go:268

	keys := make([]string, 0, len(attrs))
	for key := range attrs {
		if AttributeAllowed(key) {
			keys = append(keys, key)
		}
	}
	if len(keys) > MaxAttributes {
		return nil, fmt.Errorf("telemetry attributes exceed %d keys", MaxAttributes)
	}
	sort.Strings(keys)
	out := make(map[string]string, len(keys))
	total := 0
	for _, key := range keys {
		value := attrs[key]
		if len(key) > MaxAttributeKeyBytes {
			return nil, fmt.Errorf("telemetry attribute key exceeds %d bytes", MaxAttributeKeyBytes)
		}
		if len(value) > MaxAttributeValueBytes {
			return nil, fmt.Errorf("telemetry attribute %q exceeds %d bytes", key, MaxAttributeValueBytes)
		}
		total += len(key) + len(value)
		if total > MaxAttributesBytes {
			return nil, fmt.Errorf("telemetry attributes exceed %d bytes", MaxAttributesBytes)
		}
		out[key] = value
	}
	return out, nil
}

View on GitHub (pinned to 3ee70a1026)