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

With no annotations, the description carries the full behavioral burden, and it discloses only that this is equivalent to History.back(). It does not say what happens when there is no prior history entry, whether the call waits for navigation/load to settle, or whether it errors or no-ops — all material for an agent deciding to retry.

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?

Two short, front-loaded clauses: the operation first, the usage condition second. No filler, and the operation is stated before the guidance, which is the right ordering for a trivially simple tool.

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?

An output schema exists, so return values need not be explained, and the tool is conceptually simple. However, the required tab_id is undocumented and there is no annotation coverage, leaving behavioral edge cases (history exhausted, wait semantics) unaddressed — adequate but with clear gaps.

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 description coverage is 0% and the description never mentions tab_id at all, despite it being required. The parameter name is largely self-explanatory, which keeps this above a 1, but the description adds no meaning about which tab the history applies to or what identifier format is expected.

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 names the exact operation (History.back()) and pairs it with a concrete browser-navigation effect, so an agent can distinguish it from siblings like forward, reload, and navigate. It stops short of explicitly contrasting with those siblings, but the verb+resource is unambiguous.

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?

The 'When:' clause gives explicit triggering conditions ('undo a nav step', 'clicked wrong link', 'retry from prev page') rather than leaving usage to inference. It doesn't state when NOT to use it (e.g. first page in history) or name the forward sibling as the counterpart, so it falls short of a 5.

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