Twilio SMS MCP Server

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds valuable behavioral context beyond annotations: it clarifies that Twilio keeps metadata but clears the text, which is crucial for understanding the partial nature of this redaction. Annotations already indicate destructive (true) and idempotent (true), but the description provides specific implementation details about what gets destroyed (text) versus preserved (metadata).

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two concise sentences with zero waste. The first sentence states the action and target, the second explains the behavioral outcome and purpose. Every word earns its place in this efficiently structured description.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the destructive nature (annotations show destructiveHint: true), the description provides good context about what happens during redaction. With an output schema present, the description doesn't need to explain return values. However, it could mention that this only works on delivered messages (not scheduled or failed ones) for full completeness.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 0% schema description coverage, the description doesn't mention the 'sid' parameter at all. However, since there's only one required parameter and the schema provides a clear pattern (SM followed by 32 hex characters), the baseline is appropriate. The description doesn't compensate for the coverage gap but the simplicity of the single parameter keeps it from being lower.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the specific action ('redact'), target resource ('body of a delivered message'), and purpose ('for compliance/privacy'). It distinguishes this from siblings like sms_delete_message (full deletion) and sms_get_message (retrieval without modification).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context about when to use this tool ('for compliance/privacy') and implies it's for delivered messages only. However, it doesn't explicitly state when NOT to use it or name specific alternatives like sms_delete_message for complete removal versus metadata retention.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.