Set a specific browser tab as the default for subsequent automation calls, so later actions target the intended tab without specifying it each time.
Make a tab the default for later calls.
| Name | Required | Description | Default |
|---|---|---|---|
| tab | Yes | tab id, defaults to current |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the load. It does disclose the key behavioral trait — the change persists as the default for later calls — but says nothing about whether the tab is focused/activated, prerequisites, or failure behavior for an invalid id.
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?
One short sentence with the effect front-loaded and no waste. It errs toward under-specification rather than verbosity.
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 single-parameter tool with no output schema and no annotations, the core effect is captured, but practical context an agent needs — source of the tab id and behavior on invalid ids — is missing.
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 100%, so the 'tab id, defaults to current' documentation is already in the schema, and the description adds no further meaning. Baseline 3 applies.
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 action and effect: making a given tab the default target for subsequent calls. This distinguishes it from listing tabs (tabs), opening (new_tab) or closing (close_tab), though a reader must infer the default-target semantics from 'default for later calls' rather than an explicit statement of switching the active tab.
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?
No guidance on when to call it versus tabs, new_tab, or navigate. It does not say where the tab id comes from (presumably the tabs tool) nor what happens if the id is unknown — an agent must guess.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.