session_type

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

No annotations are present, so the description carries the full disclosure burden. It does reveal a key behavioral trait (character-by-character simulation of keyboard input) that goes beyond the name, but it does not disclose side effects on existing contents, focus requirements, or timing behavior. Some transparency is present, but the absence of any side-effect or precondition guidance leaves it at a minimum-viable level.

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 sentence with no wasted words; the core behavior is front-loaded and immediately understandable. It could be slightly more informative without becoming verbose, but as written it is appropriately sized.

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 no annotations or output schema and only 25% parameter coverage, the description is too thin. An agent still lacks guidance on the relationship between required selector and optional ref, what tabId is for, and how the tool fits among the large sibling set. The schema partially covers this, but the description contributes little to fully invoking the tool correctly on the first try.

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?

Only one of four parameters (ref) has a schema description, and the tool description mentions none of the parameters. It fails to compensate for the 25% schema coverage by not linking 'text' and 'selector' to the described behavior, or explaining tabId's role. This is a significant gap for an agent trying to construct a correct call.

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 uses a specific verb ('Type') and resource ('a field'), and adds the qualifying details 'character by character' and 'simulating real keyboard input', which clearly distinguishes it from sibling session_fill or session_press. It tells an agent exactly what action the tool performs.

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's niche (realistic, character-by-character input) but never states when to prefer it over session_fill or session_press, nor when not to use it. No explicit exclusions or alternative routing are given, leaving usage to be inferred from the behavioral hints.

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