firefox_key

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

Annotations already declare destructiveHint=true, openWorldHint=true, and idempotentHint=false, but the description adds real context the annotations cannot: the events are synthetic and may be silently ignored by the page, and Enter can trigger form submission (which explains the destructive hint). It does not cover focus requirements or what happens if ref is stale, but the added behavioral value is substantial.

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 followed by the two caveats that matter. Nothing is redundant, though the extreme terseness leaves gaps that a slightly longer description could have filled.

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 5-parameter mutating interaction with no output schema, the description covers the key behavioral risks (synthetic events, form submission) but omits tab/frame targeting semantics and the requirement for a fresh read_page snapshot. Adequate to invoke safely in the common case, incomplete for multi-frame or stale-reference scenarios.

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 only 40% across 5 parameters; only ref and snapshotId carry descriptions, and the description adds no detail on tabId or frameId at all. "Supported key" merely restates the enum that is already in the schema, and "observed element" only loosely points at the read_page prerequisite. With below-50% coverage the description needed to compensate and does not.

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 ("Send a supported key to an observed element"), which clearly separates it from the mouse-driven firefox_click and the text-driven firefox_fill without needing to name them. It stops short of explicit sibling differentiation, e.g. no mention of when to prefer click or fill.

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 line "Enter can submit forms" gives an implied usage scenario and "may be ignored by the site" warns about a failure mode, so an agent can infer when this is appropriate. However, there is no explicit when-to-use/when-not-to-use statement and no routing to alternatives like firefox_click or firefox_fill for elements that do not accept keys.

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