spawn_create_game

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

With no annotations, the description carries the full burden and does disclose real behavior: the .env write side effect, the platform-chosen engine lane, and that the result reports the lane. It omits auth/permission requirements, idempotency of game creation, and any error or revert behavior, leaving notable gaps for a mutating tool.

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 main action is front-loaded in the first sentence, and subsequent sentences each carry non-redundant information (side effect, play URL, lane behavior, follow-up tool). The final sentence is dense and slightly winding but earns its place by explaining pinning behavior.

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 no-annotation, no-output-schema creation tool the description covers purpose, a side effect, the follow-up tool, and partial return behavior ('reports which lane'). It still leaves out what the result actually returns (play URL format, game id), auth needs, and failure modes, so it is only minimally 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 description coverage is 100% for both projectDir and setVariant, so the schema already documents them; baseline is 3. The description only adds the loose mapping of the .env write to setVariant and clarifies that engine is not a parameter, without new syntax or format detail.

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 ('Create a new game in the creator's account') that an agent can act on directly. It also clarifies a non-obvious scoping detail: the engine/world pinning is not a caller argument. However, it never explicitly distinguishes itself from nearby siblings like spawn_bootstrap or spawn_init, so sibling differentiation is left implicit.

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?

Usage context is implied through the workflow note that 'spawn_init then provisions for that lane' and the instruction to keep the play URL open, which tells the agent what comes next. It stops short of explicit when-to-use/when-not guidance or naming an alternative creation path, so it is adequate but not directive.

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