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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds behavior the annotations cannot: the response contents are extensive (event timeline, 5s frame stats) and server sessions behave differently (tick windows, not frames) – the latter is a real non-obvious trait. It does not mention response size or pagination for heavy sessions, which keeps it from a 5.

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?

Front-loaded with the resource and its contents, then the id-sourcing instruction, then the server-session caveat. Dense and largely waste-free, though the long parenthetical inventory of event types is heavy in a single sentence.

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 carries the full burden of explaining returns, and it does so thoroughly enough for an agent to know what it will get. The remaining gap is operational: nothing about response size, payload limits, or whether large session timelines can be truncated.

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 the baseline is 3; the description earns a bump by explaining the provenance of session_id (from errors, hitches, rage quits, or a match) and by noting that service selects between a player session and a game-server session. It does not add anything about the game parameter beyond what the schema already states.

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 names a specific resource (one play session) and enumerates exactly what it returns: device/GPU, outcome, groups (matches, parties, runs), full event timeline, and per-5s frame stats. It also carves out a distinct case (game server sessions yield tick windows instead of frames), which cleanly separates it from siblings like glitchless_match and glitchless_events.

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?

"Use with session ids from errors, hitches, rage quits or a match" tells the agent where to source the required id, which is a genuinely useful precondition. It stops short of explicit when-not guidance or naming which sibling to prefer for aggregate vs single-session views, so it is clear context without exclusions.

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