playtest_status

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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds real behavioral detail beyond them: the max-8-image cap with even spreading, the 45-second blocking wait, and the levelEndedAt/serverMessage/warning fallbacks, but the behavioral layer here is mostly parameter mechanics rather than new information about side effects.

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 is front-loaded in the first clause and nearly every sentence carries operational information. It is, however, dense and parenthesis-heavy – 'imagesShown names their play seconds', 'the way to look at a stretch closely' – which slows parsing on an otherwise well-structured description.

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 correctly takes on the job of describing the return shape: images, screenshots list with file and playSeconds, prints, levelEndedAt, serverMessage, warning. It is nearly complete for an 8-parameter polling tool, with the gaps being maxPrints and includeScreenshots.

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?

With schema description coverage at 0%, the description does the heavy lifting for prefix, graphId, waitSeconds, screenshotsFrom and screenshotsTo, including units and the clamping limit. It leaves maxPrints and includeScreenshots wholly unexplained and only implies runId, so three of eight parameters remain undocumented.

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 outcome ('Progress or outcome of a playtest_start or scene_import_assets run') and enumerates what comes back: completed steps, log prints, screenshots. It also separates itself from the sibling playtest_frames by naming what that tool does instead ('shows any span of them side by side in one picture').

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?

Gives concrete operating instructions: poll with waitSeconds while state is still "running", expect four or five calls instead of forty, use screenshotsFrom/screenshotsTo to retarget the eight images, and use playtest_frames to inspect a stretch closely. It also warns that a succeeded run does not mean the gameplay is right, which reframes how to interpret the result.

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