Comply OSS has well-structured tool definitions with clear descriptions and proper input schemas using Zod. All 4 tools are explicitly registered with descriptions (194 - 250 chars, within baseline 34 - 392 range). Input parameters have types and descriptions. However, output schemas are not documented, responses are JSON-stringified without explicit field documentation, forcing LLMs to infer structure. Error handling is minimal (generic 'Scan failed' messages). Tool names follow verb_noun convention (comply_scan, comply_explain_license, comply_diff, comply_policy) but lack action clarity, 'comply_scan' could be clearer as 'scan_repository' or 'audit_licenses'. Parameter descriptions are adequate but lack constraint details (e.g., no min/max for arrays, no format specs for paths). No tool annotations (readOnlyHint, destructiveHint, idempotentHint) despite all tools being read-only.

• Document output schemas explicitly. For comply_scan, define: { ecosystems: [{name, licenses: [{spdxId, tier, obligations}]}], evaluations: [{packageName, status, violations}], riskScore: number }. For comply_explain_license, define: { spdxId, name, tier, copyleft, obligations: string[], distributionAnalysis: {...} }.
• Add readOnlyHint: true to all tool definitions in server.tool() calls. This signals to clients that these tools are safe to cache and retry without side effects.
• Improve error messages with recovery guidance. Instead of 'Scan failed: <message>', return: 'Scan failed: <message>. Verify the path exists and contains a package.json or go.mod file. Try comply_scan with path="." to scan the current directory.'
• Rename tools for clarity: comply_scan → scan_licenses, comply_explain_license → explain_spdx_license, comply_diff → show_compliance_changes, comply_policy → show_compliance_policy. This makes intent obvious from the name alone.
• Add parameter constraints: ecosystems array min 1 item; path must be a valid directory (add format hint); distributionModel enum values already present but could add 'default: saas' to comply_explain_license.