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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds meaningful behavioral context by detailing what the trial measures: Basics per opener, Trainer density, card appearance across hands, closing speed, and first-player bias. It does not discuss side effects or failure modes, but the read-only hint makes that less necessary.

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 sentences with no filler. The core function is front-loaded, the measured metrics are compactly listed after a colon, and the alternative-tool routing is in the second sentence. Every part earns its place.

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?

There is no output schema, so the description carries the burden of describing results; it covers the expected metric groups well (opening-hand consistency, mirror self-play, closing speed, first-player bias). It does not specify the exact result shape or labels, but the described outcomes are sufficient for an agent to invoke the tool and interpret the response.

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?

Schema description coverage is 100%, so the schema already documents deck, seed, games, hands, and locale. The description contributes an important clarification the schema does not emphasize: 'gameplay card ids, not printing ids,' which materially improves correct parameter use. It also reinforces the 'legal 20-card' requirement.

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 and resource: 'Solo-trial one legal 20-card Pokémon TCG Pocket deck.' It enumerates the two things the tool computes (opening-hand consistency and mirror self-play) and names simulate_matchup as the comparison alternative, so an agent can distinguish it from related siblings.

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?

Gives explicit routing guidance: 'Use this to tune a single deck; use simulate_matchup to compare two decks.' It also adds a practical selection constraint with 'Takes gameplay card ids, not printing ids,' which helps avoid a common invocation mistake.

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