spawn_set_variant

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

No annotations are provided, so the description carries the transparency burden. It states the primary mutation (setting an env var in .env) and its purpose, but does not disclose potential side effects such as overwriting existing values, validation behavior, or impact on any running game.

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 a single sentence that front-loads the action ('Set SPAWN_VARIANT_ID in the project .env') and appends a clarifying parenthetical. There is no redundant language; every word 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?

For a simple two-parameter tool with no output schema, the description captures the essential purpose and behavior. It lacks explicit return/error information but is largely sufficient given the schema coverage and simplicity, making it almost complete.

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 coverage is 100%, with both parameters fully described in the input schema. The description adds no new parameter details beyond reinforcing that variantId comes from spawn_list_games, so it meets the baseline for well-documented schema parameters.

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 ('Set') and resource ('SPAWN_VARIANT_ID in the project .env'), then clarifies the purpose ('join an existing game from spawn_list_games'). This clearly distinguishes it from sibling tools like spawn_create_game, which create new games.

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 parenthetical explicitly frames usage as joining an existing game from spawn_list_games, providing clear context and a workflow hint. It does not enumerate alternatives or explicit 'when not to use' scenarios, but the context strongly implies the correct scenario.

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