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

No annotations are provided, so the description must carry the full burden. It discloses the appending behavior (non-obvious W3C trait), the need for manual clearing, and error conditions (non-editable element, staleness due to navigation). It stops short of detailing exact error handling or whether typing is atomic, but the key behavioral traits are well covered.

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 efficiently written, with the core action and critical caveat front-loaded. It packs several important points (append behavior, clearing advice, session context, error conditions) into three sentences without redundancy. Minor length but high information density.

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 the tool has 3 simple parameters, no output schema, and no annotations, the description covers the necessary aspects: what it does, how to use it correctly (clearing), and failure modes. It could mention return values or exact error messages, but for an agent to invoke correctly, it is sufficient.

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 coverage is 100%, so the schema already documents the parameters. The description adds meaning by explaining the role of elementId (linking to session_find_element) and text (typed, not cleared), which goes beyond simple schema descriptions. It compensates well for the lack of enum or additional parameter hints.

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 tool types text into an element identified by elementId from session_find_element. It is distinct from siblings like session_click and device_type by explicitly naming the element-finding prerequisite and the W3C behavior.

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 explicitly warns about the appending behavior and instructs to clear the field first when replacement is intended, providing concrete alternatives (session_execute setting empty string or select-all). It also specifies the sessionId context and that it works on both browser and mobile sessions, which is more specific than generic siblings.

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