Get Current Tab

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

Annotations already establish readOnly, idempotent, non-destructive, and closed-world, so the safety bar is low. The description adds genuine behavioral context the annotations cannot: the fallback chain from the agent's own current tab to the active tab when none is set, which is the key nuance for predicting what a no-tab_id call touches.

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 front-loaded sentence that defines the resource and its resolution rule with no filler. Every clause carries meaning and the key scoping fact is stated first.

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 no-param read tool with full annotation coverage and a fully documented schema, the description supplies the essential resolution semantics. The only minor omission is what the tool returns (tab id/url/title), though with no output schema an agent might want a hint about the shape.

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% for the single tab_id param, so baseline is 3. The description goes slightly beyond the schema by spelling out the full fallback resolution ('this agent's current tab, or the active tab if it has none'), which the schema only summarizes as 'this agent's current tab'.

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 ('Get the tab') and immediately disambiguates the loaded term 'current tab' by defining it as the tab a no-tab_id call would act on. This lets an agent distinguish it from list_tabs or snapshot without opening a 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?

The description frames the tool as a resolver for default tab_id behavior, which implies when to use it, but it never explicitly states when to call this vs. siblings like list_tabs or arc_status, nor any exclusions. The concrete guidance ('pass this or call open_url first') lives in the schema, not the description.

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