The SendGrid MCP server exposes 21 tools with basic but incomplete definitions. All tools have names starting with action verbs (delete_, list_, send_, create_, add_, get_, validate_, remove_), which is good. However, descriptions are terse (mostly 50-150 chars, well below the ideal 50-200 char range for LLM optimization), input schemas are present but lack depth, output schemas are completely undocumented, and there is minimal error guidance. The server implements tool registration correctly via getToolDefinitions(), but the definitions themselves lack the rigor needed for production agentic systems. Parameter descriptions are sparse, many are generic one-liners like 'Array of email addresses to delete' without explaining constraints, valid formats, or recovery paths. No tool provides documentation of what it returns, making downstream tool composition difficult. Security-critical tools like delete_contacts and delete_list lack confirmation patterns or dry-run support. Overall, the server is functional but falls short of production-grade definition quality.

• Document output schemas for all 21 tools. Specify what fields are returned, their types, and what IDs/references are needed for downstream tool calls. Example: list_contacts should document { contacts: [ { contact_id, email, first_name, last_name, custom_fields } ], total_count }.
• Expand tool descriptions to 100-200 characters, including: (1) What does it do? (2) When use it instead of similar tools? (3) What are prerequisites (e.g. verified sender)? (4) Is it idempotent? Can it be retried? Example: 'Send a single email. Call list_verified_senders() first to find a valid sender. Idempotent if provided with a unique message_id; safe to retry.'
• Add pagination parameters (limit, offset, cursor) to list_contacts, list_templates, list_contact_lists, and list_single_sends. Default limit=20, accept up to 100. Return total_count and next_cursor in results so LLM can fetch remaining pages.
• Add confirmation/dry-run pattern for destructive tools. Example: delete_contacts with dry_run=true returns { preview: [ { email, name } ], count } without deleting. Also add guidance: 'To permanently delete, call again with dry_run=false and confirmationToken from preview.'
• Document parameter constraints in descriptions. Example: add_contact email='valid email address (RFC 5322 format, required)', custom_fields='object with arbitrary string keys and values (optional, max 255 chars per value)'. Use enums for constrained values (e.g., aggregated_by: ['day', 'week', 'month']).
• Clarify tool relationships and context for chaining. (1) create_template should document 'Returns template_id, pass to send_email with template_id parameter.' (2) send_to_list should document 'Requires sender_id from list_verified_senders() and suppression_group_id from list_suppression_groups().' (3) send_email should clarify 'Either provide template_id OR text/html, not both.'