Fingerprint report

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

readOnlyHint=true already tells the agent this is a safe inspection call, so the description's job is lighter. It does add genuine context beyond the annotation — the values are "as set for this launch," i.e., they reflect the launched browser's configuration rather than a generic template — but it says nothing about failure modes, whether a page must be open, or what the default (non-full) response shape looks like.

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 compact clauses with no filler, and the field enumeration is front-loaded before the parameter note. The telegraphic phrasing ("What this browser shows sites about the machine") is slightly awkward but not wasteful.

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 one-parameter, no-output-schema read tool this covers most of what is needed: what is returned, the field set, and what 'full' does. It omits operational preconditions (browser launched / tab context) and the default state of 'full', which matter for invoking it correctly in a suite of browser tools.

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 0% for the single 'full' parameter, so the description must carry it — and it does: 'full: every field as JSON' explains that the flag switches from a summary to a complete JSON dump. It does not state the default (false), which leaves a small gap, but meaning is clearly added beyond the bare boolean 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?

The description names the resource concretely and enumerates the exact signals reported (user agent, GPU, hardware, screen, time zone, languages, fonts, WebRTC), so an agent knows precisely what it gets back. The verb is only implicit ("what this browser shows") rather than an explicit "report/return," and there is no direct naming of a contrasting sibling, but among navigation/click/eval siblings the purpose is unmistakable.

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?

There is no when-to-use statement, no prerequisite (e.g., that a browser must be launched/open first, or which tab is inspected), and no indication of when another tool would be preferable. Usage is only inferable from the subject matter.

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