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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this with a plain 'Read-only.' Beyond the annotations, it explains output content (e.g., 'state (published, or rejected with the reason)') and the tool's role as a prerequisite for other tools, adding useful behavioral context without needing to repeat safety metadata.

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?

The description is front-loaded with the primary action and output fields, followed by a crisp 'Read-only.' and the crucial first-step note. The three example questions are helpful but slightly redundant—they restate use cases already implied—yet they do not bloat the text excessively.

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 tool with no parameters, no output schema, and full annotation coverage, the description is complete: it tells the agent what the tool does, what results to expect (fields include slug, state, rejection reason), and when to invoke it. An agent can decide to call this first without needing additional details.

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 empty schema already fully describes the input contract. The description adds no parameter details because none exist; per rubric, a zero-parameter tool receives a baseline of 4, as the description cannot add value beyond the schema.

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 states a specific action ('List this account's games') and a clear resource ('klyo games catalogue'), and enumerates the returned fields (name, slug, state, size, visits, plays). It differentiates from siblings by positioning itself as the tool to call FIRST to obtain the slug needed by other tools, so an agent can distinguish it 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?

The description gives explicit when-to-use guidance: 'Call this FIRST to learn the `slug` the other tools need.' This clearly places it before other catalogue tools, and the example questions illustrate typical use cases. It does not name dispreferred alternatives or conditions to avoid, hence the absence of explicit exclusions.

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