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

No annotations are present, so the description must carry the behavioral disclosure burden. It discloses the core action (replace text) and the recordAs substitution behavior, but does not mention failure modes, permissions, what happens to existing text, or how 'replace' differs from the 'type' sibling. The schema adds parameter detail but the description itself is sparse on behavioral context.

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?

Two sentences, front-loaded with the action and target specification, and every word adds value. The first sentence defines the core operation; the second adds a high-value security guidance without wasted detail.

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 rich input schema (34 parameters, 100% coverage) and the presence of an output schema, the description is reasonably complete for initial tool selection: it states the operation, target types, and a sensitive-text handling option. It doesn't explicitly contrast with the sibling 'type' tool, but the core semantics of 'replace' are sufficient for an agent to understand when to invoke it.

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 baseline is 3. The description slightly enhances the 'target' parameter by recommending refs/selectors after snapshot, but most parameter semantics are already fully documented in the schema. No significant additional meaning is provided for the other 32 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 uses the specific verb 'Replace' with the resource 'text in a UI input' and explicitly lists three selection methods (snapshot ref, selector, coordinates), making the tool's purpose clear and distinguishing it from general input tools like type or press.

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?

Provides clear context on target selection ('Prefer refs or selectors after snapshot') and a security-specific usage note for recordAs ('use recordAs to keep sensitive text out of a recorded replay'). It lacks an explicit 'when not to use' or comparison with the sibling 'type' tool, but the guidance given is actionable.

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