open_url

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

Annotations already declare openWorldHint=true, readOnlyHint=false, idempotentHint=false, and destructiveHint=false. The description adds meaningful context beyond those annotations: the session is new and isolated, and returned page data is untrusted. This helps an agent understand the environment and trust boundary, though it omits auth or rate-limit details.

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 short sentences, both front-loaded and purposeful. The core action is stated first, and the security warning is included without filler. Nothing is redundant or wasted.

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 tool with five parameters, a nested object, an enum, and no output schema, the description covers the core action and an important trust warning. It is minimally viable because annotations cover safety traits and the schema itself provides type/range constraints, but it lacks usage guidance and detailed parameter semantics.

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 0%, so the description carries the burden of explaining parameters. It clarifies that exactly one of url or html is expected, which adds mutual-exclusivity meaning. However, it says nothing about viewport, timeout_ms, or wait_until, leaving three of five parameters undocumented in the description.

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 verb (Open), resource (HTTP(S) URL or raw HTML document), and scope (exactly one, new isolated browser session). It implicitly distinguishes from the sibling navigate by specifying a new isolated session, but does not name any alternative explicitly.

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?

There is no explicit guidance on when to use this tool versus siblings like navigate or close_session, nor any stated prerequisites or exclusions. Usage must be inferred from the single sentence.

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