Open a Developer Tools panel for a tab

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

Annotations only declare readOnlyHint=false, so the description carries most of the burden and does add real context: the toolbox may open in a separate window, which explains why its markup isn't in the page document. That prevents a costly wrong assumption, though it doesn't say how to verify the toolbox opened or how to shut it (the close sibling handles that).

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. The MEASURED note about gDevTools.showToolboxForTab is somewhat implementation-facing and less actionable for an agent, but the rest is tight and earns its space.

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 tool with no output schema, the description covers the key behavioral surprise (separate window) and the source of valid ids. The absence of return-value detail is acceptable since there is no output schema to rely on, but a hint about confirming the panel opened would complete it.

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% with an enumerated tool id and described context parameter, so the schema already does the heavy lifting. The description's note that ids come from browser_devtools_tools is mildly useful but largely redundant since the enum is already listed.

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: open the Firefox DevTools toolbox on a tab and select one panel. It also names the sibling that supplies tool ids (browser_devtools_tools), so an agent can distinguish this from the list-tools and close-toolbox siblings without opening any 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?

It routes the agent to browser_devtools_tools for valid tool ids and explains the default tab behavior via the schema. It doesn't state when to prefer this over browser_devtools_tools or browser_devtools_close, but the context for use is clear.

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