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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description still adds real context beyond them: the account/plan gate, and the important fact that "the user plays in the interface" rather than through the tool call. It does not describe any failure mode when the plan lacks HireVue access.

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 key behavior and the no-parameter fallback are front-loaded in the first two sentences. However, the full list of eleven game names duplicates the enum in the input schema, and the affiliation disclaimer, while understandable, is not operationally useful for tool selection.

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?

An output schema exists, so return values need no explanation, and the description covers prerequisites, the optional parameter, and the read-only nature of the call. The remaining gap is relational: with siblings like start_game_session and save_game_result present, the description should clarify how opening a game relates to starting a session.

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 enum already lists the slugs, so the baseline is 3. The description adds meaning the schema lacks by explaining the consequence of omitting the parameter (a picker is shown) and by mapping slugs to human-readable game names ("Puzzle Picture", "E-Motions").

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 gives a specific verb and resource ("Shows an interactive CandidateFalcon practice game") and enumerates the available game names, so the agent knows exactly what the tool produces. It falls short of a 5 because it never distinguishes itself from the closely related sibling start_game_session, leaving ambiguity about which one actually launches practice.

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 clearly states the two usage modes: pass a game to open it, or omit the parameter to get a game picker. It also states the account prerequisite ("Requires a connected CandidateFalcon account with a games plan that includes HireVue, or Full Access"). It does not say when to prefer this over start_game_session or get_game_results, so no explicit alternatives are named.

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