browser_tab_close

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

With no annotations, the description carries the full burden. It does disclose a genuinely useful behavioral trait — the no-argument fallback to the task tab — but omits whether closing is irreversible, what happens to unsaved state, and how an invalid id or index is reported.

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 sentences, zero padding, and the primary action plus the important default are both front-loaded.

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 two-optional-param tool with no annotations and no output schema, the definition covers the main path and the default, but leaves the id/index selection conflict and index origin ambiguous — the exact details an agent needs to call it correctly every time.

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 0%, so the description must compensate. It establishes that id and index are alternative (and optional) selectors, which is real added meaning, but it never explains tab id provenance, index base (0- vs 1-based), or which wins if both are supplied.

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") plus the two selectors, and adds the zero-argument default. It is clearly distinct from siblings like browser_tab_new or browser_tab_select, though it never names those alternatives explicitly.

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?

"Without arguments closes the task tab" gives one concrete usage case, but there is no guidance on choosing between id and index, no statement of when to prefer browser_tab_select, and no note about what happens if the target tab is the only one or is in active use.

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