twilio_get_message

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile needs no restatement. The description adds nothing beyond that — no note on auth/credential handling, error behavior for invalid or expired SIDs, or rate limits.

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?

A single front-loaded sentence with no filler. It is efficient but that efficiency comes partly from omitting needed detail.

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?

With no output schema, no annotation-independent guidance, and 0% schema coverage, the description should explain what a retrieved message contains and how credentials are passed. It leaves all of that to inference, which is too thin for a tool with three required parameters.

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?

Schema description coverage is 0% across three required parameters, and the description only accounts for message_sid ('by SID'). It says nothing about account_sid (which account scope) or that auth_token is a credential that must be supplied — meaning two of three params remain undocumented in both places.

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?

States a specific verb and resource ('Get a single Twilio message') and scopes it by SID, which implicitly distinguishes it from the list-style sibling twilio_list_messages. It is clear, though it never names the sibling.

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 only usage signal is 'by SID' — an agent must infer that this tool is for when a message SID is already known. There is no explicit statement of when to prefer it over twilio_list_messages or what to do if only a phone number/date range is known.

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