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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds substantial operational context beyond them: confirming state costs one bounded check per page run in parallel, the call never fails just because nothing is foregrounded, `safariFrontmost` is omitted rather than guessed when undeterminable, and Web Inspector must be enabled in Settings. It even warns against misreading state (suspended vs. dialog-blocked look identical) and prescribes a screenshot to disambiguate.

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?

It is front-loaded with the purpose and the returned fields, and most sentences carry real information. However it runs to several dense paragraphs with visible redundancy — the 'one tab at a time / at most one foreground tab' point is made twice — and unbroken prose makes it harder to scan than the content warrants.

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?

There is no output schema, so the description must carry the full return contract, and it does: it enumerates every field (index, pageId, url, title, type, active, state, currentActiveTab, safariFrontmost) and defines each state value and its implications. Nothing needed to interpret the response or the environment prerequisites is missing.

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 only two parameters exist, one of which is explicitly 'Ignored (kept for compatibility)' in the schema itself. The description's pageId discussion concerns a returned value, not an input parameter, so it adds no meaning beyond what the schema already documents — the baseline 3 applies.

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 ('List inspectable Safari pages on an iOS device via the Web Inspector CDP bridge') and immediately enumerates the returned fields, so an agent knows exactly what it gets. It also distinguishes itself from the rest of the ios_safari_* family by explaining that those tools drive the active tab without needing this listing.

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 states when this tool is NOT needed: 'you do NOT need to list pages and thread an id just to act on the current tab, only to target a DIFFERENT one.' It also gives a concrete usage path (resolve `index` to a pageId here, then pass that pageId) and names the alternative behavior of the sibling tools.

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