List phones for outage calls

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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true), yet the description goes further by explaining the effective-call filtering rule, that in-progress phones carry a `confirmation` field with a source number and expiry, and that no write path exists via API. It stops short of describing pagination, ordering, or response shape, so it is strong but not exhaustive.

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?

Front-loaded with the core action in the first sentence, then layered with eligibility rules and field meanings. The parenthetical sibling-tool references are dense but purposeful; a small amount of additional structure (e.g., separating the eligibility rule from the field glossary) would improve scanability.

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 parameterless, side-effect-free list tool with no output schema, the description supplies everything an agent needs: what is listed, which entries are functionally active, how partially-confirmed entries are represented, and why the agent cannot mutate phones from here.

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?

The tool takes zero parameters, so there is no parameter semantics to clarify; the baseline for a parameterless tool applies. The description instead spends its words on result interpretation (status, confirmation), which is the relevant semantic gap here.

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 ('Lists the phones of the account') and immediately binds it to a purpose ('that Statuser calls when a monitor goes down'), which cleanly separates it from sibling reads like notification_email_list and actions like notification_phone_test/notification_phone_remove.

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?

Explains the context that makes the returned data meaningful (only confirmed, project-enabled phones actually receive calls) and names related sibling tools (project_channel_list, project_voice_calls_get) the agent should consult to interpret results. It also states an exclusion — phones can only be added/confirmed in the Statuser panel — but never explicitly contrasts this list tool with notification_email_list or states when to prefer one over the other.

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