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

Annotations already mark it read-only, but the description adds valuable context: 'Static; never charged, no credentials needed.' This discloses that it's immutable, free, and requires no auth—details not present in annotations.

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?

Single sentence, perfectly sized. Core purpose ('launchable modes') is front-loaded, with essential caveats (static, free, no auth) stated succinctly. No wasted words.

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 it has an output schema (so return format is defined outside the description) and zero parameters, the description covers everything an agent needs to call it correctly: purpose, static nature, cost, and auth. Nothing important 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?

Tool has zero parameters, so schema is trivially complete. Baseline for 0 params is 4; description adds no param info that's needed. No gaps to compensate.

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 it lists 'launchable modes' with a 'one-line contract for each,' which is a clear verb+resource. Its static nature and no-charge/no-credentials attributes further distinguish it from siblings like billing and runs tools.

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 implies usage: to discover available modes before launching. It doesn't explicitly name alternatives or exclusion conditions, but the purpose is clear enough that an agent would know when to call it (e.g., before runs.launch).

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