session_health

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds one genuinely non-obvious guarantee — that authentication state is not extracted — which is useful for privacy-sensitive callers, but it leaves other behavioral traits (why idempotentHint is false on a read, whether it touches a live browser connection, latency/cost) unaddressed.

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?

A single front-loaded sentence with no filler; the security caveat is appended efficiently. Slightly dense phrasing ('eligible targets', 'layout context') costs a little clarity but nothing is wasted.

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?

With no output schema, the description must carry the return-value burden, and it does list the three things read. However, it does not indicate the shape or granularity of that data, and the oddly out-of-place 'required for changes / stops before writing' schema hints on a read-only tool are not reconciled anywhere in the description.

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 both optional parameters (target_id, expected_layout_id) are already fully documented in the schema. The description's references to 'eligible targets' and 'layout context' loosely map to them but add no format or interaction detail beyond what the schema states.

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 concrete verb (Read) and enumerates the resources returned: browser version, eligible targets, and layout context. That is specific enough for an agent to know what it gets back, but it never distinguishes itself from near-neighbours like browser_capabilities, chart_health, or layout_snapshot.

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 explicit when-to-use guidance, no prerequisite, and no named alternative. The only implicit signal is that it is a read-only diagnostic, which the agent must infer from the verb and the tool name.

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