Stop a session

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

Annotations already indicate destructive, non-read-only, idempotent, and open-world behavior. The description adds valuable context beyond those flags: billing is stopped, repeats are safe, any account session id works, and cookies/logins are persisted on a normal stop. No statement contradicts the annotations.

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?

Every sentence earns its place: purpose, usage triggers, idempotence, account scope, persistence, and default-session behavior. It is front-loaded with the core action and contains no filler or redundant restatement of the title.

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 destructive tool with billing implications and no output schema, the description covers the essential operational context: why to call it, what it affects, what persists, what is safe to repeat, and what happens next. Nothing critical is missing for an agent to invoke 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 already explains that session_id can come from surfsky_session_start, a result header, or surfsky_session_list. The description adds further useful semantics: it accepts any account session id, not only ones this server started, and mentions handling of the default session.

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 opens with 'Stop a session and its billing,' naming a specific verb, resource, and consequence. It also distinguishes itself from sibling session tools by framing it as termination/cleanup, and from the broader browser-action siblings by focusing on session lifecycle.

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 explicitly says to use this tool when a task is done or to clean up a leaked session found with surfsky_session_list. It also clarifies that stopping the default session is fine and that the next browser call starts a fresh one, giving an agent practical boundaries for safe usage.

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