siyuan-note/siyuan · warning

validation exceeded %s

Error message

validation exceeded %s

What it means

Thrown by validateResolved when schema.Validate(value) does not return within toolValidationTime (2s) after acquiring a slot. Unlike error 365 (could not start), this means validation started but the jsonschema evaluator is taking too long — typically due to catastrophic regex backtracking, exponential $ref combinatorics, or an enormous value against a complex schema.

Source

Thrown at kernel/mcp/tools/validation.go:186

		return ctx.Err()
	case <-timer.C:
		return fmt.Errorf("validation did not start within %s", toolValidationTime)
	}

	result := make(chan error, 1)
	go func() {
		err := schema.Validate(value)
		<-validationSlots
		result <- err
	}()

	select {
	case err := <-result:
		return err
	case <-ctx.Done():
		return ctx.Err()
	case <-timer.C:
		return fmt.Errorf("validation exceeded %s", toolValidationTime)
	}
}

func validateJSONComplexity(value any, maxDepth, maxNodes int) error {
	nodes := 0
	var walk func(any, int) error
	walk = func(current any, depth int) error {
		if depth > maxDepth {
			return fmt.Errorf("JSON depth exceeds %d", maxDepth)
		}
		nodes++
		if nodes > maxNodes {
			return fmt.Errorf("JSON node count exceeds %d", maxNodes)
		}
		switch typed := current.(type) {
		case map[string]any:
			for _, child := range typed {
				if err := walk(child, depth+1); err != nil {

View on GitHub (pinned to 251596fc0d)

Solutions

1. Simplify the schema: replace risky regexes with anchored, linear patterns; flatten or bound recursive $ref definitions; prune redundant anyOf/oneOf branches.
2. Reduce the value size (see error 364) so validation has less work.
3. Pre-validate expensive constraints incrementally or cache compiled (Resolved) schemas.
4. If unavoidable, surface a clear user-facing message and degrade gracefully rather than retrying the same slow validation.

Example fix

// before: regex vulnerable to catastrophic backtracking
{"pattern": "^(a+)+$"}
// after: anchored, linear pattern
{"pattern": "^a*$"}

err := validator.ValidateInputContext(ctx, args)
if err != nil && strings.Contains(err.Error(), "validation exceeded") {
    // schema is too slow against this value: simplify schema or shrink value
}

When it happens

Trigger: A single schema.Validate(value) call runs longer than 2s. Common with patterns vulnerable to ReDoS, deeply recursive schemas, or validating a multi-megabyte value against a schema with many constraints.

Common situations: A tool schema includes a user-supplied regex that backtracks catastrophically; a schema uses recursive $ref structures that explode against nested data; validating a near-8 MiB value against a schema with many anyOf/oneOf branches.

Related errors

• validation did not start within %s
• tools/list returned an empty response
• tools/list repeated cursor %q
• unsupported server type: %s
• command is required for stdio server

AI-assisted analysis of siyuan-note/siyuan@251596fc0d (2026-08-12). Data as JSON: /api/errors/343d1745488164f9. Report an issue: GitHub.