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

The readOnlyHint annotation already declares the operation safe, so the description only needs to add context beyond that. It adds useful behavioral context: the tool is a status/diagnostic call that reveals plan-dependent data and can be used after a limit-based refusal. No contradiction or hidden side effects are implied.

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 short sentences, front-loaded with the returned data and followed by usage guidance. Every phrase contributes meaning, and there is no redundant restatement of the tool name or schema.

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 zero-parameter, read-only status tool with an output schema present, the description covers what the tool returns and when to call it. Nothing an agent needs in order to invoke 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 has zero parameters and schema coverage is 100%, so the schema leaves nothing undocumented. The description appropriately does not need to explain parameters; it earns the baseline of 4 for a parameterless tool.

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?

The description clearly enumerates the concrete data returned: tariff, project slot occupancy, and remaining daily limits on the paid plan. Although it uses a noun phrase rather than an explicit 'returns' verb, the resource set is specific and unique among the listed siblings, so an agent can understand exactly what this tool provides.

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?

The description gives explicit invocation timing: 'Зови в начале сессии' (call at the start of the session) and 'когда другой тул отказал по лимиту' (when another tool refused due to a limit). This is strong, actionable guidance that tells the agent both when to call and in which fallback scenario.

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