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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, and the description adds genuine context beyond them: no arguments are accepted, limits cannot be raised here, reserved jobs count toward both ceilings, both applicable ceilings constrain admission, and the response shape is described. That is materially more than the annotation set provides.

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 purpose and return shape, then alternatives. It is dense with distinct facts rather than padding, though the several semicolon-clauses make it slightly heavier than needed for a no-argument read tool.

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?

With no parameters, no output schema, and no nested objects, the description carries the entire burden and does so: it states the return fields, the target_key semantics, the constraint behavior, and where to go for adjacent concerns. Nothing an agent needs 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?

There are zero parameters, so the baseline is 4; the schema itself is fully described ('No arguments. Send an empty object'). The description's target_key discussion concerns a field in the returned budgets array rather than an input, so it adds return-value clarity but no parameter semantics.

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 opens with a precise verb+resource: read the authenticated company's monthly company-wide and API-key spending ceilings plus charged, reserved and exposure credits. It also names the exact return fields (current UTC month, budgets array) and distinguishes the scope via target_key, so an agent can separate it from sibling billing/usage tools without reading a schema.

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?

It explicitly routes to alternatives with conditions: use skavio_wallet for credit funds, skavio_adapter_usage for the separate lifetime MCP ceiling, and the dashboard for changing policies. It also states the negative case ('takes no arguments and cannot raise a limit'), leaving nothing to inference.

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