Get message status

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds that failures carry an error message and lists the possible status values, but that overlaps with the output schema and adds no auth, rate-limit, or partial-result behavior.

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?

Two sentences, front-loaded with the operation and its cardinality, followed by usage. The status enumeration is long but earns its place by telling the agent what values to expect.

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 one-parameter read tool with an output schema, the description covers the input format, expected result states, and when to call it. The only gap is not distinguishing itself from the sibling list_messages for the no-known-id case.

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 0%, so the description must carry the load, and it does: it names the id format (msg_...), the accepted cardinality (1 to 20), and that these are message identifiers. Only the array semantics of the single `ids` param are left implicit.

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 — read the current status of 1 to 20 messages by id — and enumerates the status values returned. The id-based lookup is clearly distinct from list_messages or get_campaign siblings.

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?

Explicitly gives two use cases: confirm delivery after a send, and diagnose a failure. It does not name the sibling alternative (e.g., list_messages for browsing without known ids), so routing is clear but not fully comparative.

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