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

Annotations already declare readOnlyHint and destructiveHint=false, so the description earns credit for adding genuinely new behavior: that nothing is marked read by this call, that results are previews rather than full threads, and how channel defaults and the limit cap behave. The remaining gap is return specifics such as total counts or preview contents, which is minor against the annotation coverage.

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?

Three tight sentences, front-loaded with what is returned and in what order, followed by parameter constraints and then sibling routing. Every sentence carries distinct information with no repetition of the schema.

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 three required parameters and no output schema, the description supplies what an agent needs: the shape of a result (one preview per thread with conversationId), ordering, paging defaults and caps, and the handoff to getTextConversation. Nothing needed to call it correctly is missing.

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 coverage is 100%, so the baseline is 3, but the description adds default values not present in the schema (channel default ALL is repeated, page starts at 1, limit default 20 with max 30) and the enum meaning of WEB as website chat. It stops short of adding anything about paging edge cases.

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 ('List the newest text conversations') plus scope and ordering ('one preview per thread with its conversationId, newest first'), and names the channel coverage (SMS, email, website chat). An agent can distinguish it from getTextConversation and search without opening any schema.

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?

Gives explicit routing: browse recent messages here, use search to find a thread by name/phone/words, and pass a conversationId to getTextConversation to read a whole thread. Both alternatives and the condition selecting each are stated, not implied.

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