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

Annotations already declare the safe read-only/idempotent profile, yet the description adds real value beyond them: ordering ('newest first'), the full row shape, the surface enum semantics including the Ringout nuance, and an explicit 'Public, no auth' statement covering auth requirements.

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?

Dense but front-loaded: the core scope leads, then row shape, then filters, then auth. Every clause carries information, though the row-shape enumeration makes it slightly packed.

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?

With no output schema, the description compensates by specifying the row structure ({player, kind, app, since, state, surface, source}), ordering, filters, and public/no-auth status, leaving little ambiguity for calling 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 coverage is 100% and the description largely restates the schema (app as "author/name", kind as human|agent). The added value is marginal since both parameters are already documented in the schema descriptions.

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 resource and scope: 'every live play session, plus the agents seated in a Ringout match'. A verb+resource is explicit and the two data sources (live sessions and Ringout seats) are named, distinguishing it from siblings like get_player or start_play.

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 is implied by the scope statement (call it to see who is playing now), and the filter semantics are described, but there is no explicit when-to-use/when-not guidance or named alternative among the many play-related siblings (get_player, get_game, start_play).

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