Click

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

Annotations (readOnlyHint=false, openWorldHint=true) already establish that clicking mutates state and touches an external browser. The description adds genuine value beyond that by disclosing a concrete behavioral trait: 'Reports any navigation, console errors, or network activity the click triggered.' This is non-obvious side-effect reporting that an agent could not infer from annotations or schema. No contradiction with annotations.

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, each earning its place: purpose, addressing strategy, and behavioral reporting. No filler, front-loaded with the action verb. The actionable guidance (prefer latest-snapshot refs) appears early. Nothing redundant with the schema is restated at length.

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 carries the return-value burden and does partially meet it by disclosing that navigation, console errors, and network activity are reported. For a 9-parameter click tool with one required field and heavy schema coverage, this is reasonably complete. Minor gaps: no detail on error behavior when the element is not found and no description of the response format.

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 78%, so the schema already documents the parameters well — baseline 3. The description adds marginal value by clarifying the relationship between the three addressing modes (ref/css/role+name) and noting refs come from the latest snapshot, but this overlaps the schema's own 'Preferred — refs are exact' note. It doesn't deepen semantics much 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+resource: 'Clicks an element.' The purpose is unambiguous and readily distinguished from browser_hover, browser_type, and browser_press_key by the click verb. It does not explicitly name sibling alternatives, which keeps it at 4 rather than 5, but the core action is clear.

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?

Implied usage — the description tells the agent how to address the element ('by ref... or by css, or by role+name') and that refs come from the latest browser_snapshot, which is genuinely helpful. However, it never states when to use this tool versus the sibling interaction tools (hover, type, select_option, scroll) or names any exclusions, so the when-to-use guidance is left to inference.

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