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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false; the description reinforces this with "opens nothing by itself," which resolves the apparent tension between the mutating name and the read-only hint. It adds useful context beyond the annotations — the step-by-step return shape and the absence of a public Squire API — though it says nothing about prerequisites such as the user being signed in.

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 behavioral core (what it returns, that it opens nothing, and what to run next) is front-loaded in two dense sentences. The closing note on Squire's API status is awkwardly phrased as "Squire's official API: Squire has no public API" and carries a future-dated check stamp, which is slightly noisy but still justifies why browser automation is required.

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 responsibly explains the return value as a step-by-step guide covering screens, buttons and fields. For a zero-parameter, read-only guide tool this is close to complete; it could add a note on what the agent should do if the steps fail or the account state does not match.

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 tool takes zero parameters, so there is no parameter meaning for the description to supply. Baseline of 4 applies; nothing here is missing or misleading about inputs.

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 ("Block time off in the user's own Squire account") and immediately clarifies the actual behavior: it returns step-by-step instructions rather than performing the action. That distinction separates it from siblings like squire_book_appointment and squire_cancel_appointment, which an agent could otherwise confuse with it.

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 names the follow-on path — "then do it with the cotlet_browser_* tools in the user's Squire Cloud Browser" — which tells the agent this tool is a planning step, not an executor. It does not state when not to use it (e.g., versus a direct booking tool), so it stops short of full when/when-not guidance.

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