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

Annotations already cover read-only/idempotent/non-destructive, so the description only needs supplementary context. It adds two real facts: results are ordered newest first, and the status filter's domain is SENT/FAILED/SKIPPED. It doesn't state pagination behavior or whether account and campaign filters can be combined.

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 compact sentences, front-loaded with the read marker and resource, then ordering, then filters, then the status domain. No filler; every clause carries information.

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?

No output schema and 7 params, so the description should do more: pagination semantics (defaults page=1, per_page=50), response shape, and whether filters are mutually exclusive are all unaddressed. It's adequate to invoke but not fully complete.

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% across 7 params, so the description must carry weight. It does document the account/campaign filters (id or uuid) and enumerates the status values the schema leaves unconstrained – genuinely useful. However page and per_page are entirely undocumented anywhere, leaving a clear gap.

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 + resource: lists sent SMS messages, with an explicit ordering rule (newest first). The scope note ('Sent messages') and optional account/campaign scoping clearly separate it from siblings like list_sms_campaigns or get_sms_report, though it never names those alternatives.

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?

Usage is implied by 'Sent messages, optionally of one account / campaign' – the agent can infer filtering behavior. But there is no explicit statement of when to use this versus get_sms_report, list_sms_optouts, or get_sms_campaign, and no exclusions or prerequisites.

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