Read incoming SMS

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

Despite annotations already declaring readOnly/idempotent/non-destructive, the description adds substantive behavior: no read-receipt side effects, late or offline uploads can be backdated, and nextCursor can be null on a final page. The closing warning that SMS text is untrusted data is a genuinely useful safety disclosure for an agent consuming the result.

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?

Purpose is front-loaded in the first sentence, followed by side-effect exclusions, pagination, polling strategy, and the untrusted-data caveat. Every sentence carries distinct information with no repetition of schema or annotation content.

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, the description still conveys enough about the response surface (nextCursor, hasMore) and its edge cases for an agent to drive pagination correctly. Combined with the safety caveat and polling semantics, an agent has what it needs to call this repeatedly and safely.

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 63%, and the description compensates for key gaps by explaining cursor-vs-page pagination, that nextCursor may be null, and that time-window filtering should be overlapped because of backdated uploads. It does not touch search, limit, order, or device_id, leaving those to the schema.

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 ('Retrieve incoming messages') plus the scope constraint that only messages already synchronized by the Android phone are returned. It does not explicitly distinguish itself from the sibling smsportal_list_messages, so an agent still has to infer the direction split between the two listing tools.

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 concrete operational guidance: paginate with page or nextCursor/hasMore, and for repeated polling use overlapping time windows with deduplication. It stops short of saying when to prefer this over smsportal_list_messages or the other siblings, so no explicit exclusions are offered.

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