Stop a playtest

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

Annotations only declare it is not read-only, not idempotent, and not destructive; the description adds substantive context beyond that — it waits for a pending action before closing the browser page, invalidates the session id, and terminates the browser. That invalidation detail is exactly the kind of consequence an agent needs before calling it, though it does not discuss failure behavior if the session is already gone.

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, side effects follow in parentheses, and the call-to-action closes the text. The enumerated return-summary list is somewhat redundant given an output schema exists and makes the first sentence long, but no sentence is filler.

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 single-parameter session-termination tool this covers the full picture: what it terminates, the sequencing behavior, the post-condition (session id dead), and when to invoke it. Return values are also sketched, so even without consulting the output schema an agent knows what comes back.

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 single parameter is documented as "Session id returned by gamealia_playtest", so the schema already carries the semantics. The description only indirectly reinforces this by noting the id stops working afterwards; baseline 3 applies when the schema does the work.

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 verb and resource ("Ends a session started by gamealia_playtest") and explicitly names the sibling that creates the session, so an agent can pair playtest/playtest_stop without inspecting schemas. The parenthetical side effects and return summary further pin down what the tool is.

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?

"Call it when done playing, so the session does not hold a browser until it expires" gives a clear trigger plus the reason, and the opening clause ties it to sessions created by gamealia_playtest. No explicit when-not guidance is needed since no sibling competes for this job, but the exclusion case is left implicit.

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