Navigate current tab

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

Annotations already mark the tool as unsafe and destructive, and the description adds meaningful behavioral detail: cookies and tabs are retained, navigation returns a fresh snapshot, and previous references become invalidated. This goes beyond the annotation flags and clarifies the real-world side effect of using the tool.

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 sentences carry the full purpose, supported actions, and key behavioral consequence with no filler. The most important scoping fact ('existing session') is front-loaded, and the invalidation warning is compactly placed.

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 navigation tool with no output schema, the description covers the essential semantics: what the tool does, which actions are supported, what is preserved, and what happens to prior snapshots. It is slightly incomplete on url semantics and route selection versus sibling tools, but it gives enough for a confident call.

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?

With only 33% schema description coverage, the description should compensate for undocumented parameters, especially url. It mostly restates the action enum already present in the schema and does not explain how url applies (e.g., that it is required for goto and irrelevant for back/forward/reload). The description adds little parameter-level meaning beyond the schema.

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 states a specific action ('Navigate') with a clear resource: an existing session's current tab, and enumerates the supported operations (goto, back, forward, reload). It is distinct from sibling tools like tab_open, which creates a session, by anchoring usage to an already-existing session.

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 phrase 'within an existing session' provides clear context for when this tool applies, implying it should be used after a session has been created rather than to create one. It does not explicitly name alternatives or state when not to use it, so it stops 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.