Three tools with complete input schemas and descriptions. Naming follows verb_noun pattern (generate_*, upload_*). Descriptions are detailed (150-250 chars) and explain prerequisites. All parameters have types and descriptions. However, output schemas are not documented in the visible code, only inferred from descriptions. Error handling is mentioned in descriptions but not formalized in the schema. No tool annotations (readOnlyHint, destructiveHint, idempotentHint) present.

• Document output schemas for all three tools. Specify exact fields returned (e.g., 'Returns {file_path: string, thumbnail_url: string, width: number, height: number}') so agents can chain calls and extract data reliably.
• Add tool annotations: mark all three tools with destructiveHint=true since they perform file I/O and S3 writes. This signals to agents that these calls have side effects.
• Formalize error handling in descriptions. Add: 'On error, returns {error: string, code: string, retryable: boolean, suggestion?: string}' so agents know whether to retry or ask the user.
• Add validation constraints to 'output_dir' parameter: specify that it must be an absolute path, must exist and be writable, and optionally add a max file size constraint (e.g., 'max 100MB per image').
• Consider splitting 'generate_and_upload_gemini_s3' into separate tools or document it as a convenience wrapper. If kept, clarify in the description that it is idempotent (same prompt + params = same URL) so agents can safely retry.