fill

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states what the tool does but doesn't describe important behavioral aspects: whether this triggers form submission events, validation, or side effects; what happens if the UID doesn't exist; whether it works on disabled/readonly fields; or error conditions. The description provides basic functionality but lacks operational context needed for safe use.

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 extremely concise - a single sentence that efficiently communicates the core functionality. It's front-loaded with the essential action and target, with no wasted words or unnecessary elaboration. Every word earns its place in this minimal description.

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 mutation tool (filling form fields) with no annotations and no output schema, the description is insufficient. It doesn't cover important contextual information: what the tool returns (success/failure indicators), error conditions, side effects, or prerequisites (needing a snapshot first). The 100% schema coverage helps with parameters but doesn't compensate for the lack of behavioral and operational context needed for safe tool invocation.

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 100%, so parameters are fully documented in the schema. The description adds minimal value beyond the schema - it mentions 'UID from snapshot' which slightly clarifies the uid parameter context, but doesn't provide additional semantic information about parameter interactions, constraints, or usage patterns beyond what's already in the schema descriptions.

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 ('fill') and target ('form field') with specific element types mentioned (input, textarea, select). It distinguishes from siblings like 'fill_form' by specifying individual field filling via UID rather than form-level operations. However, it doesn't explicitly contrast with other form-related tools beyond naming.

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?

No guidance is provided on when to use this tool versus alternatives like 'fill_form' or other form interaction tools. The description mentions the UID comes from a snapshot, implying prerequisite steps, but doesn't state this explicitly or provide context about appropriate use cases versus other form-filling approaches.

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