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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description's "read-only" adds little, and "takes no arguments" merely restates the empty schema. What it does add beyond annotations is the shape of the result — the five returned fields and the three possible status values (active, paused, limited). It stops short of saying whether results are paginated or ordered, which is the only remaining behavioral gap.

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?

Three compact sentences, each doing distinct work: what is returned, when to call it, and its calling profile. The most decision-relevant line — call it first to get plan_id — is front-loaded right after the purpose.

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?

There is no output schema, so the description carries the return-value burden itself, and it does so by listing the returned fields and status enum. For a zero-parameter, read-only list tool, nothing an agent needs in order to call 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?

The tool takes zero parameters, so the baseline is 4. The description correctly notes it takes no arguments, matching the empty schema with additionalProperties=false, and adds nothing misleading.

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 ("List all proxy plans on the account") and enumerates the returned fields — id, label, proxy type, status, remaining traffic — so the agent knows exactly what comes back. It is clearly distinguishable from get_plan and get_proxy_lines, which return a single plan or its lines.

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?

"Call it first to find the plan_id that get_plan and get_proxy_lines need" gives an explicit ordering rule and names the two alternatives plus the prerequisite that selects them. There is no ambiguity about when to reach for this tool versus its siblings.

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