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

No annotations, so the description carries the full behavioral burden. It discloses that no money moves, that an immediate cancellation is irreversible, the authentication/prerequisite requirements, and the typical 409 nothing_to_undo error.

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-loads the core effect ('Keep a VPS...') and then layers in the exact scope, side-effect behavior, prerequisite, and error in a compact paragraph. Every sentence contributes relevant operational detail.

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?

Given no annotations, no output schema, and full schema coverage for the lone parameter, the description supplies everything an agent needs: scope, prerequisites, irreversibility boundary, state-check tool, and failure mode.

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?

Only one parameter (service_id), and schema description coverage is 100%; the schema already explains the accepted service code format and numeric-id fallback. The description adds no parameter-level semantics beyond that.

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 (undo) and resource (scheduled end_of_period cancellation), and distinguishes itself from cancel_service by describing the opposite operation and the exact cancellation type it applies to. An agent can tell it apart from siblings without opening schemas.

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?

Explicitly states when it works (scheduled end_of_period cancellation) and when it cannot (immediate cancellation, VM destroyed at once). It also points to get_vps_status as the way to check can_undo, leaving little inference.

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