session_select_option

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

No annotations are provided, so the description carries most of the behavioral burden. It does provide the useful prerequisite that a session must already be started, and states it selects by value/label/index rather than by coordinate. It does not describe side effects, errors, or how the selection is applied beyond those basics.

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?

The description is two short sentences with no filler. It front-loads the main action and then states the key prerequisite. It earns each word, although it is too brief to support the 0% schema description coverage.

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 small session interaction tool, the description covers the core action and the preconditions, and an output schema exists so the response shape does not need describing. However, it remains incomplete on how the parameters behave, especially selector and max_chars, and on what to do when the session is not active.

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?

The schema description coverage is 0%, so the tool description must compensate. It partially clarifies the 'value' parameter by noting that value/label/index are accepted, but it does not clarify how these modes are distinguished, nor what `selector` must contain, nor the meaning of `max_chars`. This is insufficient for the three parameters defined in 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?

The description states a clear action: select an option in a <select> element, and specifies the matching criteria: by value, label, or index. It identifies the resource and behavior well, but it does not explicitly contrast it with sibling tools like browser_click/type or session_click/type.

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 description implies the tool is used when a select-option needs to be chosen in an active browser session and explicitly states the session_start prerequisite. However, it gives no guidance about when to prefer this tool over session_click, session_type, or session_form_fill, so the selection context is only implicit.

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