close_tab

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

With no annotations present, the description carries the full burden, and it does disclose one meaningful behavioral limit: the last tab cannot be closed. It stops short of saying what an attempt actually does (error, no-op), whether the tab's page state is lost, or whether it acts on the current tab when no id is given.

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?

A single compact sentence that front-loads the action and appends the exception and alternative in a parenthetical. Every clause earns its place.

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 one-optional-parameter tool with full schema coverage and no output schema, the description supplies enough to call it correctly and know when not to. The only gap is the outcome of a failed close, which is low-stakes for this operation.

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 the single `tab` parameter is already documented as 'tab id, defaults to current'. The description reinforces the default-to-current behavior only indirectly via the sibling contrast; it adds no id format, sourcing, or bounds information 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?

States a specific verb and resource ('Close a tab') and immediately contrasts it with the sibling `close` tool ('use close to shut down'), so an agent can distinguish the two without opening either schema.

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?

Gives an explicit constraint-plus-alternative: if the target is the last tab, this tool cannot be used and `close` is the correct routing. It does not mention `switch_tab` as the way to make a non-current tab the target, which leaves one small inference for the agent.

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