Capture a credential from a web panel (blind)

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

With no annotations provided, the description carries the full behavioral burden and does so well: it discloses server-owned browser execution, allowlisted sites, human login and approval, step execution, editability, DOM extraction, and the narrow return values including failure shape. It also explicitly states that page text, HTML, and screenshots are never returned.

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 front-loaded with the security-critical ownership distinction and then proceeds through login, approval, step execution, extraction, and return values. Every sentence contributes relevant operational or safety context without filler.

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 complex nested-parameter tool with no output schema and no annotations, the description supplies the essential operational model, safety boundaries, human-in-the-loop behavior, and exact success/failure response shapes. An agent can understand when to use it and what to expect from 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?

The description adds meaningful semantics for the step types and extractor behavior, including that steps are declared and run after human approval. However, with seven parameters and low schema description coverage, it does not explain several top-level inputs such as site, url, destination, or metadata fields, so it only partially compensates for the schema gap.

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 states a specific operation: opening a server-owned browser on an allowlisted site, having the person log in, running declared steps, and extracting the credential into the store. It clearly distinguishes the tool from browser tools the agent controls by emphasizing that the page is server-owned and the credential never reaches the agent.

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?

It gives an explicit routing rule: prefer this over any browser tool you control when a page shows a secret. This names the alternative category and the condition that selects this tool, leaving little ambiguity for an agent choosing among tools.

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