Signal Channel is a two-tool STDIO server with moderate definition quality. Both tools (reply, send) have clear action verb naming and are properly described. However, critical gaps exist: (1) reply's input schema lacks descriptions for the 'recipient' parameter (phone number format, validation requirements not specified), (2) send's description is functional but verbose and includes implementation detail ('No phone number needed') that could confuse LLMs about when to use reply vs send, (3) no output schemas are documented for either tool, LLMs cannot plan downstream actions or understand what data is returned, (4) no error handling guidance, LLMs will have no recovery path if a message fails to send. The parameter schemas themselves are present and typed (string types are visible), which prevents a lower score, but the lack of parameter descriptions and missing output documentation are critical gaps for production readiness.

• Add explicit parameter descriptions to reply: recipient should state expected format (e.g. 'Phone number in E.164 format (e.g. +1-555-0123) or Signal ID matching the sender attribute from channel message'), and text should state any length limits or content restrictions.
• Document output schemas for both tools. Example for send: '{"type": "object", "properties": {"success": {"type": "boolean"}, "messageId": {"type": "string"}, "timestamp": {"type": "string", "format": "date-time"}}, "required": ["success"]}'
• Clarify the distinction between send and reply in tool descriptions. send description should say 'Send a message to the channel owner's account (the Signal phone number configured in this server). Use this when the user wants to send a message to themselves or the server owner.' reply should say 'Send a message back to a specific sender who has contacted the channel. The recipient must be an allowed sender in the access list.'
• Add error handling guidance: both tools should document common failure modes (invalid phone, network error, sender not allowed for reply) with suggested recovery (e.g. 'If recipient is not found, check the allowlist with the access manager').
• Add enum or pattern constraint for recipient parameter. If only E.164 format is accepted, add 'pattern: ^\+?[1-9]\d{1,14}$' to the schema.
• Consider adding a validation parameter or dedicated validation tool to check if a phone number is allowed before attempting reply, reducing failed calls.

Inferred effective spec: <=2025-11-25.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry