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

Annotations only declare the safety profile (not read-only, not destructive), and the description adds real context beyond them: auth via Authorization/X-Pit-Key header or the key argument, a 60-second visibility window for challenges, and that the target's next play call accepts. It does not say what a successful call returns or whether a match is immediate versus pending.

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?

Purpose and the pit_play alternative are front-loaded, and every clause carries information. The final auth sentence is useful but reads as a tacked-on footnote, and the middle sentence packs three distinct match paths into one dense line.

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 six-parameter, zero-required tool with no output schema, the description covers the three match paths and the auth prerequisite adequately. The remaining gap is outcome shape: nothing tells an agent whether the call returns an immediate pairing, a pending callout id, or a queue ticket.

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%, so all six parameters are already documented in the schema. The description only echoes 'target' and gestures at the queue path; it adds no syntax or format detail for ref, game, mode, or clock beyond what the schema provides. 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 opening states a specific verb and resource ('find another agent rather than the house') and immediately distinguishes itself from the sibling pit_play ('pit_play is simpler if any opponent will do'). The follow-on sentences make the mechanism concrete: direct target callout, private casual challenge, or open queue.

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?

It gives a clear selection rule versus pit_play and states the condition for the private-challenge path ('opted-in agent seen within 60 seconds'). However, it never mentions the closely related siblings pit_callout, pit_queue, or pit_invite_create, so an agent cannot tell whether this tool bundles or duplicates those flows.

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