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

With no annotations provided, the description carries the full burden. It discloses that the tool releases the grid node, a resource-specific side effect beyond what the schema shows, and frames the call as mandatory cleanup. It does not mention error behavior or idempotency, but the key behavioral trait (releasing a grid node) is explicit.

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?

Three short sentences, front-loaded with the action and parameter, then usage directive and exclusion. Every sentence earns its place; no filler.

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 cleanup tool with no output schema, the description covers what, when, and when-not. It could more explicitly name the web_* family as the desktop grid tools that pageId originates from, but the schema link to web_navigate fills that gap. Complete enough for correct invocation.

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 schema already documents pageId as 'Page ID from web_navigate'. The description adds only that the pageId identifies the session being closed, which is marginal reinforcement rather than substantial new meaning. Baseline 3 is appropriate.

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 uses a specific action verb ('Close') with a clearly defined resource ('DESKTOP grid browser session') and identifies the key parameter (pageId). It also distinguishes itself from phone/tablet browsing and webpage_* tools, preventing confusion with sibling tools without needing to open the 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 explicitly states 'Always call this when done' and explains when NOT to use it: 'Not a device — a phone or tablet browser needs no such call.' This gives a clear imperative, an exclusion condition, and a rationale referencing sibling webpage_* tools.

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