chrome_activate

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

With no annotations, the description carries the full burden and does so well: it declares fail-closed behavior on stale snapshot, route, capability, or DOM identity, and forbids coordinate fallback. It stops short of describing what activation actually performs (click/keypress) or any return/confirmation signal.

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 dense sentences with zero waste; the core action is front-loaded and the failure/prohibition constraints follow immediately.

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-parameter mutation tool with no annotations and no output schema, the definition covers preconditions, failure modes, and the prohibited alternative. The remaining gap is what a successful activation returns or how success is confirmed.

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 snapshot_id's ephemeral/perishable nature and node_id's snapshot-local exactness are already documented in the schema. The description reinforces these constraints but adds no syntax or format detail 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 (activate) and a precisely scoped resource: one exact actionable node from the immediately preceding chrome_read snapshot. The chrome_read lineage separates it from the ax_* family, though no sibling is explicitly named as an alternative.

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 a clear precondition ('immediately preceding chrome_read snapshot') and an explicit exclusion ('coordinate fallback is forbidden'), which routes the agent away from coordinate-based tools like left_click. It does not directly compare against ax_activate, but the context is unambiguous.

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