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

The annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context beyond them: 'opens nothing by itself' tells the agent no browser action is taken, and the return format (screens, buttons, fields) is disclosed. It stops short of stating any auth or account-prerequisite behavior if the user is not logged into Pirate Ship.

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 core constraint is front-loaded in the first clause and the follow-on workflow comes last, which is the right order. The middle sentence is a run-on stitched with a semicolon ('...opens nothing by itself; then do it with...'), which costs some readability 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 zero-parameter, no-output-schema guide tool, the description covers what it returns and how it fits into the browser-tool workflow, which is what an agent needs to chain correctly. The only real gap is the absence of any precondition about the user's Pirate Ship session or account state.

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?

The schema has zero parameters at 100% coverage, so the baseline is 4. There is no parameter meaning for the description to add, and it correctly does not invent any.

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?

Names a specific verb and resource ('Track shipment in the user's own Pirate Ship account') and immediately disambiguates what kind of tool it is: it returns step-by-step instructions rather than performing the action. The closing line about there being no official Pirate Ship API further pins down the tool's role against the mutating siblings like pirate_ship_get_rates.

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?

Explicitly routes the agent: this tool first, then 'do it with the cotlet_browser_* tools in the user's Pirate Ship Cloud Browser.' That is a clear when-to-use and a named follow-on family of alternatives. It lacks an explicit exclusion (e.g., when not to use this versus cotlet_app_guide), which keeps it below a 5.

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