form_input

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

With no annotations provided, the description must fully disclose behavioral traits. It only states the action and the tab prerequisite, but omits any detail about side effects (e.g., whether setting values triggers change events, submit, or requires specific page states). For a mutation tool, this is insufficient.

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 sentences, with the core action in the first and a conditional prerequisite in the second. No wasted words; all information is relevant.

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?

The tool has a simple structure with three well-documented parameters and an output schema (per context). The description covers the essential workflow – obtaining ref and valid tab ID – which is sufficient for an experienced agent. It lacks some behavioral nuance, but that is more transparency than completeness.

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 already provides descriptions for all three parameters (100% coverage), but the description adds cross-references: ref comes from read_page/find, and tabId from tabs_context. This enhances understanding of how to populate the parameters.

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 a specific action: 'Set values in form elements using element reference ID from the read_page or find tools.' It also distinguishes the tool by specifying the required input source (ref from read_page/find), which differentiates it from broader form filling tools like form_fill.

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 provides clear workflow guidance: use read_page/find to obtain a ref, and use tabs_context if a valid tab ID is not available. However, it does not explicitly compare itself to sibling tools like form_fill or act_on, nor does it state when NOT to use this tool.

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