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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description goes beyond them by disclosing the return payload (per-message status codes such as DELIVRD/UNDELIV/FAILED, error, price charged) and a real operational constraint about high-volume polling, which is exactly the kind of non-obvious behavior an agent needs.

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?

One dense sentence covering purpose, identifier source, return fields, and the polling caveat, followed by the raw endpoint. Zero filler and the most important information is front-loaded.

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 compensates by enumerating the returned fields (status, error, price). For a single-parameter read tool with read-only annotations, nothing needed to invoke or interpret 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 description coverage is 100% and there is a single required parameter, so the baseline is 3. The description adds provenance (the id comes from messente_send_sms) but no format, length, or edge-case 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?

States a specific verb (get) and resource (delivery report of a sent message) keyed by omnimessage_id, and explicitly names the sibling that produces that id (messente_send_sms). An agent can distinguish this from messente_get_statistics or messente_get_prices without opening another 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 clear context for use (after sending, via the id returned by messente_send_sms) and an explicit usage caution: Messente asks not to poll this for every message at scale. It stops short of naming a preferred alternative for bulk status (e.g., statistics or webhooks), so it is strong but not a full when/when-not/alternative routing.

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