session_type

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says that input is performed and that session_start is required; it does not mention side effects, error conditions, page state requirements, or what happens with the max_chars limit. The behavioral transparency is thin.

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 action and then gives the prerequisite. Every sentence contributes useful information, making it appropriately concise.

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?

Given that an output schema exists, return values are covered elsewhere, and the description names the action, selector mechanism, and dependency on session_start. However, there are no annotations and no parameter descriptions, so the agent is left guessing about max_chars, failure modes, and target visibility. The description is minimally viable but not complete.

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%, so the description must explain the parameters. It does clarify that selector is a CSS selector and implies text is the value being entered, but it does not explain max_chars or provide additional detail for text beyond the schema. This is only partial compensation.

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 clearly states the action: entering text into a field on a live session page using a CSS selector. It also names the required prerequisite, session_start. However, it does not explicitly distinguish this from sibling tools like browser_type or session_click, so it falls just short of a 5.

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 gives one usage constraint: 'Requires session_start.' This implies it should be used only within a live session, but it does not explain when to choose this tool over alternatives or provide exclusions. The prerequisite provides some guidance, but no when-not-to-use context.

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