Read received texts

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

Annotations already declare this is read-only, idempotent and open-world, so the safety profile is covered. The description still adds real context beyond the annotations: results come back newest-first, the sync setting is off by default, and only texts arriving after it is enabled will ever appear, which prevents an agent from misreading an empty result as 'no messages'.

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?

The lead sentence front-loads what is returned, and the two follow-up bullets handle prerequisites and safety. Every sentence adds information an agent would otherwise have to guess at; there is no filler.

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?

For a read-only list tool with a full schema and an output schema, the description covers prerequisites and ordering, so it is nearly complete. The only small gap is that it does not mention the paging defaults or point to list_phones for deviceId, though the schema supplies both.

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?

All five parameters have full schema descriptions, so the schema carries the parameter documentation burden and the baseline is 3. The description only implies which filter to reach for ('filter with phone', 'since a time') and adds no syntax or default detail beyond what the schema already states.

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?

Specific verb (read) plus resource (received SMS) plus scope (what the user's phones received, newest first) plus the exact fields returned: sender, words, time, receiving phone. That wording cleanly separates it from siblings like send_sms and get_message_status, which deal with outbound traffic and delivery state.

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?

It gives concrete use cases ('see replies to texts the user sent', 'what arrived since a time') and the filter that selects each one. It also states a hard when-not condition: the key must be opted in for received texts, and the phone app must sync received texts, which is off by default.

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