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

Beyond the readOnlyHint annotation, the description discloses that behavior is deterministic, uses a heuristic AI policy, and returns specific summary metrics and a sample log. It also clarifies that results reflect the AI policy rather than human performance, adding meaningful interpretive context beyond the 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?

The description is three sentences with no filler. It front-loads the core action, then lists outputs, then clarifies the tool's interpretational boundary. Every sentence 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?

With no output schema, the description adequately covers high-level return values: wins, draws, failures, average turns/actions, and a sample game log. It also explains the AI policy limitation. It stops short of specifying the exact output structure, but is complete enough for an agent to select and invoke the tool correctly.

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 baseline is 3. The description does not add parameter-specific meaning beyond what the schema already provides, but it also does not need to since the schema fully documents deck, seed, games, and locale.

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 uses a specific verb and resource: 'Run two legal 20-card Pokémon TCG Pocket decks through the Battle Lab rules engine' using deterministic heuristic AI. It clearly distinguishes itself by stating it measures the built-in AI policy, not human skill or competitive win probability, which separates it from evaluation 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 gives clear context: use this for deterministic AI-vs-AI matchup simulation and not for estimating human skill or competitive win probability. It provides a clear when-not-to-use signal, though it does not explicitly name sibling alternatives such as evaluate_deck or trial_deck.

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