Create game lobby and optionally start matchmaking

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

Annotations already flag destructive and non-idempotent behavior, but the description adds crucial specifics: it replaces an existing lobby on another queue, rolls back a newly created lobby if search fails, and lists the required write-allowlist endpoints. This is rich behavioral context beyond the structured 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 front-loaded with the core action, then adds only essential behavioral notes, usage routing, and prerequisite endpoints. Every sentence earns its place with no filler.

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 two-parameter mutation tool with no output schema, the description covers purpose, side effects, rollback behavior, alternatives, and auth requirements. An agent has everything needed to invoke it 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 both parameters are already documented in the schema. The description adds queue ID examples and clarifies that startMatchmaking means immediately searching, but this largely mirrors schema content. Baseline 3 applies when the schema does the heavy lifting.

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 (creates) and resource (custom or matchmade lobby) and defines scope via queue examples and optional matchmaking. It clearly distinguishes itself from siblings like lol_workflow_matchmaking_accept and lol_static.

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?

Explicitly says when to use it (set up queues or queue up with a party), when to use alternatives (accept ready check with lol_workflow_matchmaking_accept; look up queue IDs with lol_static), and instructs to prefer this over manual REST calls or lol_eval.

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