ygo_build_meta_deck

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

With no annotations supplied, the description carries the full burden and does so well: it discloses internal re-validation of banlist, sizes and Extra Deck placement before returning, and documents a failure mode (available:false plus availableArchetypes) with an explicit guarantee that no substitute deck is fabricated. Those are the exact behaviors an agent needs to trust and interpret the output.

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?

It is front-loaded with the trigger phrase, then layers constraints, validation behavior, and failure handling in a logical order. Slight redundancy between 'Never output a decklist from memory' and 'every card must come from this tool's response' costs it a point but nothing is genuinely wasteful.

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 generative tool with no output schema and no annotations, the definition covers legality constraints, validation, and the failure path, which is most of what an agent needs. It is slightly thin on what a successful response contains (strategy/staples/list shape), leaving the agent to discover the payload structure at call time.

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% and every parameter is self-documented, so the schema already does the explanatory work. The description only echoes the deck-size range and format list that the schema's enum and min/max already encode, adding no new semantics such as what values are acceptable for archetype or how goSecond changes the build. Baseline 3 applies.

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 opens with a specific verb and resource (build a tournament-legal decklist) and immediately scopes it: 40-60 Main, up to 15 Extra, 15 Side, banlist-respecting across five named formats. That is enough for an agent to separate this from siblings like ygo_find_community_decks or ygo_optimize_deck without opening the schema.

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 trigger is stated explicitly and forcefully ('USE THIS whenever the user asks you to build, produce or suggest a decklist') plus a clear negative rule ('Never output a decklist from memory'). What is missing is naming the alternative sibling to use when the user instead wants community lists or optimization of an existing list, so it stops short of full when/when-not/alternatives guidance.

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